Happens to me every time i go full throttle, pedal to the floor and then let off. I hear that loud ass POP from the exhaust! :)Quote:
Originally Posted by UselessPickles
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Happens to me every time i go full throttle, pedal to the floor and then let off. I hear that loud ass POP from the exhaust! :)Quote:
Originally Posted by UselessPickles
It happens to me also. Jeff please try this. Put the gear in second and at 1500 rpm press full throttle. Tell me what happens before it reach 2500.Quote:
Originally Posted by NOLAjeeper
I promised Dan to shoot a video but didn't have a chance.
By the way i don't know why i received a short elbow pipe which is between the intercooler and the turbo, seems like the gave me an extension pipe to add, but when i saw Jeff close setup then realised that i got it wrong. Now every time i boost on hills the pipe comes out.
If I try that today, I'll probably crash because it's snowing here :)Quote:
Originally Posted by jeepsking
When I recently recorded a data log to make the boost curve chart, that was full throttle in second gear from about 1500 rpm. I don't remember anything particularly bad happening, other than just generally not accelerating very quickly until after 2500 rpm.
It's been so long since I've driven with a stock engine that I can't tell whether it's slower, faster, or the same as stock in the low rpm range. Part of the sluggish feeling is likely due to relative comparison to how hard it accelerates above 2500 rpm, but I think there's still some issues with the tune in that area as well.
My data logs still show long-term fuel trims suddenly going extremely negative at 1500 rpm, then suddenly returning to more "normal" values around 2600 rpm. When accelerating lightly/moderately in 1st gear, especially with a cold engine, I feel a sudden decrease in power as I pass 1500 rpm, then a sudden jerk and surge in power right around 2600-2800 rpm. The severity varies with the amount of throttle I'm using, and the problem becomes fairly subtle when the engine is fully warmed up. The relationship between the long-term fuel trims and the acceleration behavior seems to close to be coincidence, and seems to me to indicate a problem with the tune. If tuned properly, the computer should not have to take away 20+% fuel in the 1500-2600 rpm range.
Have you gotten a custom tune from Prodigy yet?
The longer 1-piece silicone elbow that I have is a newer part that Prodigy now has custom ordered for the stage 2 kit. The shorter elbow that you have is a "standard" size (easy for Prodigy to obtain) that they used at first before getting the custom size. The shorter version requires a short metal pipe to be used as a coupler to attach a short extension of silicone hose to reach the turbo. You'll end up with 3 hose clamps in a row, right next to each other to connect the turbo, extension, coupler and elbow all together.Quote:
Originally Posted by jeepsking
There's not much room for error, so you just need to get the coupler perfectly centered between the elbow and extension, get the hose clamps lined up perfectly and make sure all the hose clamps are tight. You also might need to double-check the angle of the compressor housing outlet compared to the angle of the silicone hose to make sure they are meeting each other in a straight line. The silicone hose only overlaps the compressor outlet just barely enough to use a hose clamp. Get that hose clamp right up to the very edge of the silicon to ensure that it is fully clamping down against the compressor outlet, rather than trying to squeeze the silicone off the end of the compressor outlet.
Here's an update on my setup of the PCV system. First, a refresher of what I did with the PCV hose (hose from the PCV valve to the intake manifold): http://jeeplab.com/showthread.php?13...ull=1#post2116
What I didn't talk about back then was the other half of the system: the "make up air" hose, which in stock form allows fresh filtered air from the air filter box to enter the crankcase, replacing the air that was sucked out through the PCV valve.
At the time of my previous posts about the PCV system, Prodigy was still working on how to deal with that side of things. When I first received the stage 1 kit, they completely disabled the PCV system and simply tied both vents from the engine together into a road draft tube, which is just nasty, messy and smelly.
When Prodigy sent me the parts to hook up the PCV hose with a check valve, the instructions had me keep the road draft tube hooked up to the "make up air" vent on the engine. This was unacceptable, because air gets sucked INTO the engine through that tube now! That just seemed like a disaster waiting to happen (tires kicking up dust under the vehicle where the end of the tube is, submerging the tube in water, etc). I immediately ran out to an auto parts store and found a breather filter that I was able to rig up satisfactorily to the original make up air hose, but it was kinda ugly and temporary, so i didn't show it off. Prodigy told me at the time that they were still working on finalizing their solution to the make-up air side of the PCV system.
I have since received a small breather filter (smaller than the hideous monstrosity I had rigged up) from Prodigy with a hose coupler that I believe is intended to be used to attach the filter to the end of the rubber hose that had previously connected to the air filter box. That just so happens to be the same curvy rubber hose that I sacrificed to modify the PCV hose (in the link at the beginning of this post) so I could add the check valve into the system while retaining an OEM look with the formed plastic hose.
So here's the OEM "make up air" hose without its curvy rubber hose:
http://www.uselesspickles.com/files/...v_update_1.jpg
The breather filter conveniently fits right onto the end of that plastic hose:
http://www.uselesspickles.com/files/...v_update_2.jpg
Highlighted in that photo are:
- The breather filter.
- Zip ties holding the heater hoses away from the filter, and also preventing them from touching the intake manifold way in the back.
- A zip tie holding a small plastic vacuum line up. That vacuum line used to be connected directly to the intake manifold, holding it in place. But now with the rubber vacuum hose used to tee in the BOV sensing line, it wants to fall down onto the oil filter cap.
A close-up of how the heater hoses are anchored with zip ties:
http://www.uselesspickles.com/files/...v_update_3.jpg
I like the final result. As close to OEM appearance as I can get:
http://www.uselesspickles.com/files/...v_update_4.jpg
With the breather filter mounted directly onto the plastic hose, it gets hidden by the the plastic engine cover.
Since there was recent talk about adding oil catch cans to the supercharger setups, I think it's worth mentioning that the Prodigy setup doesn't have any oil vapors going through the turbo or intercooler. The only time oil vapors are entering the intake is when there's vacuum in the intake manifold pulling oil air directly through the PCV hose. When you're making boost, it's all fresh air coming in.
The down-side to this setup is that when you are making boost, piston blow-by gasses pressurized the crankcase and cause oily vapors to flow backwards through the the "make-up air hose", through the breather filter, and dumping out to atmosphere under the hood. This is not ideal because:
- Pollution. It definitely won't meet emissions requirements. Won't even pass a visual inspection, if you have those in your region.
- Sometimes you can smell that oily air, especially after some full throttle in the summer with the top down, then coming to a stop or slowing down soon afterward.
- When hooked up in stock form, there's a slight amount of vacuum in the air filter box under high engine load conditions that helps suck the blow-by gasses out of the crankcase through the make-up air hose. When venting to atmosphere, it's a bit less efficient at keeping the crankcase air clean.
In the future, I'd like to explore the option of adding a hose fitting to the end of the air filter (the main air filter on the turbo) so that I can run the make-up air hose through an oil catch can and back into the air filter for a fully closed PCV system. Less pollution, no oily smells ever, and slightly cleaner crankcase air. The only problem is that the tune from Prodigy was designed with purely fresh air when on boost, so I would run the risk of knocking/detonation as a result of lowered effective octane from whatever oil makes it past the catch can. To be 100% safe, I think this would require some serious testing/monitoring by someone that knows what they're doing to determine whether a custom slightly less aggressive tune is necessary to keep things safe. I'm not sure I'll ever get motivated enough to be willing to pay for professional testing and possibly custom tuning for this.
I may discuss with Prodigy at some point to see if they think it would be safe enough to setup, then send them some data logs afterward to see if any tweaks to the tune are necessary.
I just found some more pictures worth posting...
http://www.uselesspickles.com/files/...ntercooler.jpg
http://www.uselesspickles.com/files/...iat_sensor.jpg
Installing stage 2 was a husband/wife bonding experience :)
Thats very cool that your wife comes out to help. Mine will get dirty when she has to but otherwise she is happier keeping me company and filled with liquids.
When Prodigy sent me the parts to hook up the PCV hose with a check valve, the instructions had me keep the road draft tube hooked up to the "make up air" vent on the engine. This was unacceptable, because air gets sucked INTO the engine through that tube now! That just seemed like a disaster waiting to happen (tires kicking up dust under the vehicle where the end of the tube is, submerging the tube in water, etc). I immediately ran out to an auto parts store and found a breather filter that I was able to rig up satisfactorily to the original make up air hose, but it was kinda ugly and temporary, so i didn't show it off. Prodigy told me at the time that they were still working on finalizing their solution to the make-up air side of the PCV system.
I have since received a small breather filter (smaller than the hideous monstrosity I had rigged up) from Prodigy with a hose coupler that I believe is intended to be used to attach the filter to the end of the rubber hose that had previously connected to the air filter box. That just so happens to be the same curvy rubber hose that I sacrificed to modify the PCV hose (in the link at the beginning of this post) so I could add the check valve into the system while retaining an OEM look with the formed plastic hose.
Jeff, that breather is hooked up to the hose that is attached on the drive side of the engine, that vents out to the atmosphere and hangs above the transmission? Thats that hose right?
Yup. But to say that it "vents out" above the transmission is misleading, because the engine actively sucks air IN through that hose any time there is vacuum in the manifold!
I'm reusing the original plastic breather hose, so Prodigy's hose is not involved in my setup at all.
Now that I think of it, Prodigy's intent with this new breather filter may be to simply attach it to the end of their breather hose that hangs above the transmission. This would at least filter the air coming into the crankcase, and would minimize oily smell by not being in the engine compartment, but I wouldn't want my crankcase vent down there when I'm splashing through mud/water. I really don't know what the latest official Prodigy setup is now with regards to the PCV system.
In case you are interested in obtaining new OEM hoses for the PCV system, a dealer should be able to easily find them in their system if you describe it to them as "pcv hose" and "make-up air hose". One was $15.85 and the other was $17.50.
May i recommend as you mentioned earlier us with the ripp are adding oil catch cans for the pcv systems i suggest adding one to your turbo setup as any forced induction motor should have one from what my tuner told me. Also the boost entering the pcv system essentially pressurizing the crank case is not a very good thing to do it puts more uneeded stress on internals. Ripp sells the check valve for the pcv system for 60 bucks or comes standard on the kit it lets the manifold suck air thru when not under boost but when boost enters it closes and no boost will enter the crank case
2k13jk: Review the design of the PCV system with the Prodigy kit as I've described (admittedly, scattered across a couple posts)...
Keep in mind that there's two importantly distinct sides of the PCV system:
1) PCV hose, running from the PCV valve to the intake manifold.
2) Breather, or make-up air hose, from an open valve cover vent (no check valve of any type) to the intake system, somewhere up-stream from the throttle body (not a vacuum source), but down-stream from the air filter (source of fresh filtered air).
There already is a check valve in the PCV hose with the Prodigy kit: http://jeeplab.com/showthread.php?13...ull=1#post2116
So there is no boost directly entering the crankcase.
Normal operation for the PCV system is that manifold vacuum sucks air out of the crankcase through the PCV hose. The breather hose allows fresh, filtered air to enter the crankcase, replacing the oily air that was sucked out.
But when on boost, cylinder pressures are much higher than a non-boosted engine, which creates quite a bit more piston blow-by than a non-boosted engine. This causes a reverse airflow from the crankcase through the breather, because that's the only exit path available (The check valve in the PCV hose is held closed by manifold boost pressure). This happens with all the boosted systems.
With the supercharger setups, the breather hose is connected back up to the intake system (like the stock setup). This is why you get oil in the intercooler and supercharger. And this is why adding a catch can to this hose can improve on-boost performance, and even allow for a "hotter" tune.
With the Prodigy kit, the breather hose has its own air filter and is NOT connected back up to the intake system. The Prodigy kit does not suffer from the consequences of oily crankcase air when on boost. I fully described this in my recent post about my PCV setup, including reasons that it's not ideal, and that I'd really prefer to eventually run it through a catch can and back into the intake.
Adding a catch can to the PCV hose has less of an impact on a boosted engine, because oily air only comes through that hose when there is vacuum in the manifold (partial throttle, light load, not when trying to make big power). A catch can here does not prevent oil from coating the inside of the intercooler, because this hose is a direct line from the crankcase to the intake manifold, skipping past the whole intake system.
So now for my leaking power steering fluid story...
After installing the new power steering hose, there were no obvious leaks. But as time went by, I started to notice there was a damp spot on the steering gearbox around the hose fitting. It slowly grew bigger over time. So one day, I decided I would get in there with a wrench and just snug it up a bit tighter to stop the leak. The next day, the entire gearbox was completely soaked in a thick coat of fluid, and the fluid level in the reservoir had visibly dropped.
So I ended up out in the driveway in the dark (got a late start in the evening) with a head lamp, going through the whole messy process of removing the power steering hose again so that I could hopefully find an obvious cause for a leak.
And it was luckily quite obvious:
http://www.uselesspickles.com/files/...se_adapter.jpg
The OEM power steering hose has funky ends that appear to be a small compression fitting with an o-ring. From some quick searching, this seems to be a common type of hose fitting for power steering lines (probably other high pressure hydraulic lines too). The new hose in the stage 2 kit has "AN" style flared compression fittings, and comes with adapters (one pictured above).
Some googling taught me that you need to pre-lube the o-rings on these fittings before installing, and then also not over-tighten them, or else you can damage the o-ring and cause a leak. I didn't pre-lube it when I installed it, which probably partially damaged it. Then tightening it more to try to stop the leak just damaged it more.
A trip to a small local hardware store in the morning was all I needed to find a replacement o-ring that was very close in size. This time, I pre-lubed the o-rings with fluid (ATF-4 is what the manual calls for in the power steering system, btw), and followed some advice I found for tightening: gently thread it in until you feel it "bottom out" (obvious sudden increase in resistance), then just snug it up about another 1/8 turn. It doesn't need to be super tight.
The tricky part is that the AN flared fitting needs to be tightened more tightly, so you should hold the adapter steady with a second wrench while tightening the hose onto it to avoid accidentally indirectly over-tightening the adapter.
I'm learning all kinds of stuff from my mistakes with this turbo install :)
Jeff i had the same issue with the power steering leak. O ring was damaged. 3rd day after the install of the stage 2 is when i noticed a puddle of pink fluid under the jeep. Took it back to the shop and they replaced the O ring. Havent had a problem since.Quote:
Originally Posted by UselessPickles
Hi,
On Friday i went to dunes with my JK . It was fun, but i experience a high vibration on road. Check the wheel balance all ok. Check the shaft (transfer shaft bolt were loose ) and then i saw this ...... :(
Ugh. are you sure all your pipes are geometrically correct? i remember it was tight getting everything in.Quote:
Originally Posted by jeepsking
and this is a side question, as its answer has no bearing. how hard were you wheeling? high speed? big twist? did you hear a "CLUNG" sound at any point?
Hi Ross,Quote:
Originally Posted by JeepLab
This pipe is rigid, so i don't think i can change any angle. Yes as i stated before that i drive extremely off road with high speed (60mph). I don't blame PD they have done an excellent work putting a turbo kit in a pentastar JK , but i hope that they revise the routing of driver side manifold.
That actually makes a lot of sense now that I think about it. There's no clearance issue between that pipe and the front driveshaft with a stock track bar. But if you use a longer track bar with a suspension lift to re-center the front axle, that will push the front axle closer to the pipe (toward passenger side) when the suspension is compressed to the point of normal stock ride height (when the track bar is level).Quote:
Originally Posted by jeepsking
The stock suspension setup has the trackbar level when at normal ride height, and the axle swings *away* from that pipe (toward the driver side) if the suspension either compresses or extends from normal ride height.
I think the solution will be to extend the trackbar mounts (frame mount downward and/or axle mount upward) so that you can use a shorter track bar that is closer to being level when at normal ride height.
Hi Jeff,Quote:
Originally Posted by UselessPickles
I have 2" lift JKS with teraflex adjustable front track bar. What should i do now ?
Quote:
Originally Posted by jeepsking
Paging Dr. Pickles!
LOL. how clutch is that guy? you know he's got the answer.
For now, you could shorten the track bar to be about as long as the stock track bar. Maybe a little longer than stock will be OK. You'll basically have to find a compromise between having exhaust clearance, and having the front axle close to centered.Quote:
Originally Posted by jeepsking
As you make adjustments, have a heavy friend or two jump on the front bumper while you watch the path of the drive shaft, checking for clearance between exhaust and driveshaft.
I have a 2" AEV spacer lift with the stock track bar. My front axle is close enough to being centered that it's not worth getting an adjustable track bar. Since my kit is a spacer kit, it gives me exactly 2" lift. If you you have a spring lift, then you might actually have more than 2" lift, and your axle might be more off-center than mine.
I still think the ultimate solution would be modified track bar mounts to allow you to use a stock-length track bar that sits level at normal ride height. That would probably require some custom work (fabrication, welding, etc).
Time to solve the problem of the vulnerable coolant reservoir. Just as a reminder, the Prodigy instructions currently have you mount the reservoir behind the front bumper:
http://www.uselesspickles.com/files/...installed1.jpg
Dan from Prodigy shared a picture of an alternate location that an install shop thought of. I liked it so much, that I relocated mine similarly:
http://www.uselesspickles.com/files/...elocate_10.jpg
I really like this location better. It's not exposed to trail damage. The vent is not exposed to road spray, rainwater, puddles, etc. The cap is easy to access for checking fluid level and refilling. The reservoir is level with the top of the radiator with a short hose connecting them. This is basically the ideal location for the reservoir.
The reservoir has threaded holes that allow us to bolt it to the plastic wall, with a bolt coming from the other side of that wall. That means we need to get the TIPM (Totally Integrated Power Module) out of the way to access the other side of the wall.
Start by moving whatever this thing is. It just slides up off its mounting tab, then push it aside:
http://www.uselesspickles.com/files/...relocate_1.jpg
That will give us a little more room to push the TIPM aside.
Next, remove the TIPM. Use a flat blade screwdriver to unlatch the 4 mounting tabs. You'll have to lift up on the TIPM at each corner as you unlatch to ensure that it fully disengages:
http://www.uselesspickles.com/files/...relocate_2.jpg
http://www.uselesspickles.com/files/...relocate_3.jpg
These plastic ribs need to be trimmed so that the reservoir can sit as low and as close to the wall as possible:
http://www.uselesspickles.com/files/...relocate_4.jpg
I just used a Dremel with a sanding drum. Remove the air filter to get some more working room:
http://www.uselesspickles.com/files/...relocate_5.jpg
Once you trim enough plastic out of the way, hold the reservoir in place while using a 1/4 inch drill bit to mark where you'll drill a hole through the plastic wall:
http://www.uselesspickles.com/files/...relocate_6.jpg
NOTE: Only the lower mounting hole is being used. There's no space for a bolt head to fit on the other side of the plastic wall in the location of the upper mounting hole.
The fun part is drilling the hole. There's not enough space to get a hand-held drill in there, especially with the turbo in place. I used the Dremel again. A small drill bit was used to start the hole, then I used what I believe is called a "cone burr" ( narrow cone-shaped grinding/filing bit) to slowly/carefully ream the hole out larger until my bolt just barely fit through:
http://www.uselesspickles.com/files/...relocate_7.jpg
http://www.uselesspickles.com/files/...relocate_8.jpg
That's a 5/16 inch diameter, 18 pitch thread bolt. I learned the hard way that the mounting hole on the reservoir is NOT threaded all the way through. I started with a 1-1/4 inch long bolt, but bottomed it out on the threads of the reservoir before I could tighten it down. I ended up cutting about 1/4 inch off the bolt. To be safe, I would probably buy a 3/4-inch long bolt if I were doing this again.
Mount the reservoir with that bolt and tighten it down good. It's very solid with only one bolt holding it:
http://www.uselesspickles.com/files/...relocate_9.jpg
Then you just need to cut an appropriate length of hose from the original coolant reservoir hose, hook it up to the radiator, install the TIPM, and install that other thing that was move aside at the beginning:
http://www.uselesspickles.com/files/...elocate_10.jpg
There's plenty of clearance from the turbo and air filter:
http://www.uselesspickles.com/files/...elocate_11.jpg
http://www.uselesspickles.com/files/...elocate_12.jpg
And the final overall view of my install with this latest change:
http://www.uselesspickles.com/files/...de_update1.jpg
http://www.uselesspickles.com/files/...op_update1.jpg
Thanks for the compliment. The idea is to share the infos so whoever face it know's what to do.Quote:
Originally Posted by Rexx19
Jeff, thanks again and i will adjust the track bar as you said cause i already have one and not tends to get the mount (which is a better solution as u said).
To be honest i thought about the same location of the recovery tank because i have AEV bumper which u can't put the tank on it .but didn't had the time to relocate.
For the time being my front drive shaft is out for trouble shooting (no vibration now ) and the shaft looks ok (i guess ) let see what happens next.
The cause of vibration :)
^^^Time for an upgrade.
WHOA.Quote:
Originally Posted by jeepsking
Did you feel it all at once? or was the change gradual?
Yes. It came all once.Quote:
Originally Posted by JeepLab
I have ordered a heavy duty shaft from Curtis taton. Hopefully i will get it in December.
MOAR BOOST!
I think I may have finally solved my exhaust leak. I installed a new "header" gasket (where the exhaust pipe mounts to the exhaust port of the engine) on the driver side where I had a stubborn leak. I now have seen boost peaking in the 8.0-8.3 psi range! Previously, I was only getting up to the 7.8-8.0 range. I seem to be on par with NOLA with boost numbers now. The highest I saw today was 8.58 psi in 4th gear. I wimped out at 120mph, but it was still accelerating.
Even better than higher peak boost is that I'm building boost a bit earlier in the rpm range now.
In 2nd gear:
1 psi at 2250 rpm
2 psi at 2600 rpm
3 psi at 2800 rpm
4 psi at 2900 rpm
5 psi at 3100 rpm
6 psi at 3300 rpm
7 psi at 3500 rpm
8 psi at 3900 rpm
I need to get a nice clean data log of a 2nd gear pull to create an updated boost curve chart...
Keep it coming!Quote:
Originally Posted by UselessPickles
As you wish!Quote:
Originally Posted by JeepLab
I got a nice clean data log of a 2nd gear full throttle pull. Here's my new boost curve:
http://www.uselesspickles.com/files/...ar_update1.png
And here it is compared to my boost curve with the exhaust leak:
http://www.uselesspickles.com/files/...ak_compare.png
Lesson: Make sure your exhaust system is leak free when you have a turbo, or else you'll be missing out on power and turbo response!
And for a fun comparison, I found this dyno chart of a RIPP supercharged 3.6 Wrangler, with a boost curve. Notice that the boost curve is not actually linear. It seems to be a shallow exponential curve. If it was linear, it would have 5 psi around 3250 rpm (half peak boost at half peak engine speed), but it doesn't actually reach 5 psi until 4600 rpm!
http://www.uselesspickles.com/files/...ripp_chart.jpg
GRRR... my charts are getting shrunk because of ads to the point that they are difficult to read.
1) There needs to be a better way to allow ads to display in posts without making the entire right side of the screen unusable to post content. That's just a huge waste of space and leads to unnecessary shrinkage of images. Does the forum software or ad plugin have other options for how to display ads? Maybe display them between posts rather than inside posts? Or maybe have ads occupy a horizontal section of the post rather than an entire vertical section?
2) What happened to the feature that allowed us to click images to view them in full size?
1. its vbulletins template, i cant alter it.Quote:
Originally Posted by UselessPickles
2. what kind of files are they. Upload as jpgs and it will think they are pics and make them full size when you click them.
I'm hot-linking to images on my own web server ("From URL" option in the "Insert Image" dialog).
[QUOTE=UselessPickles;3705]MOAR BOOST!
I now have seen boost peaking in the 8.0-8.3 psi range! Previously, I was only getting up to the 7.8-8.0 range. I seem to be on par with NOLA with boost numbers now. The highest I saw today was 8.58 psi in 4th gear."
Forgive me for asking, I'm only doing so for my own information, but it appears the boost numbers you are seeing are no better than what is seen for a supercharger with a standard pully, let alone the high elevation pully that seems to bring the boost up to 11 PSI. If I recall, the sales pitch on a turbo vs. SC was that it was suppose to spin up faster and provide more boost, but from your information here that doesn't appear to be the case? Am I missing something on this? Please know, this question is NOT a jab at anyone that has a chosen a turbo over an SC, I'm just trying to understand the differences for when it comes time for me to pick one.
BTW, JeepLab, you get that high elevation pully on yet? Any feedback? It appears you should have been seeing about a 30% increase in boost!
[QUOTE=Timmy;3727]I had the SC out and separated, but I could not remove the pulley!Quote:
Originally Posted by UselessPickles
I don't think anyone ever claimed that the turbo would produce more boost than the superchargers, but only that the turbo would produce more power. A turbo produces power more efficiently than a supercharger because it is using heat energy from the exhaust that would be otherwise thrown away out the tail pipe. The superchargers get their power directly from the crankshaft, so there is more parasitic power loss. Given a turbo and a supercharger that produce the same peak boost, the turbo will produce more net power to the drivetrain.Quote:
Originally Posted by Timmy
For the RIPP (and other centrifugal superchargers) specifically, even with the 11 psi high altitude pulley, you only get that 11 psi at 6500 rpm (and only if running down near sea level). The chart I posted with the RIPP boost curve appears to be with the high altitude pulley, because it gets up to just over 10 psi. Compare that boost curve to my boost curve. If the additional boost of the high altitude pulley being run at low elevations is enough to catch up with or surpass the power of the turbo, it will only beat the turbo near redline.
Somewhat unrelated, but speaking of high altitude pulleys...
The intent of the high altitude pulley is to compensate for thinner air at higher elevations, and produce the same amount of boost up there as the normal pulley would produce near sea level. With a given pulley, a supercharger will lose boost as go up into higher elevations.
The turbo, however, adjusts to changing elevations automatically. Its boost is controlled by a wastegate, which is calibrated to open up when boost pressure exceeds a fixed amount of pressure above ambient pressure. My turbo will produce about 8.2 psi peak boost at sea level, and up in the mountains, without making any adjustments.
This is why planes are turbo props. You couldn't use a supercharger on a plane. You'd crash.Quote:
Originally Posted by UselessPickles
But you can add a wastegate to a supercharger, no? Especially a centrifugal one.
Thanks Pickles, food for thought when making a decision between the two.Quote:
Originally Posted by UselessPickles
Technically, yes, you could setup a supercharger system with a wastegate (or some sort of precision bypass valve) on the intake somewhere after the supercharger. Then you could use a smaller pulley wheel to over-spin the supercharger some, while relying on the wastegate/bypass to limit boost. With a centrifugal supercharger, this would give you peak boost before redline, then hold peak boost up to redline. With other types of superchargers, it would just over-work the supercharger constantly unless you drove up to a higher elevation.Quote:
Originally Posted by FieryRobot
The big difference between this idea and how a wastegate fits into a turbo system is that on a turbo, the wastegate limits the speed of the turbo. The wastegate bleeds off exhaust, around the turbine side of the turbo, limiting the turbo speed, and indirectly limiting boost. With the supercharger setup, the wastegate would be directly bleeding off boost pressure, but the supercharger would still be spinning faster than necessary to generate the controlled amount of boost. Faster supercharger = less efficient = more heat.
This variable ratio ProCharger looks pretty cool, though: http://www.lsxtv.com/news/procharger...-supercharger/
I think Pickles is spot on. And, I don't mean to hijack this portion of the thread but since we're talking about bypasses and wastegates and how to make desired power I thought I'd "share."Quote:
Originally Posted by UselessPickles
The engineers for these power mods are much smarter than me so I'm sure there is a good reason for bypassing superchargers. I'd just like to know what it is. I understand wastegate operation on a turbo. The turbo boost is not linear with exhaust flow. There's no ideal blade pitch for low RMP through high RPM. Pick a good one for lower RPM operation which would produce too much boost at high RPM and adjust by bypassing exhaust. It's elegant. Makes sense to me, that is, unless the wastegate is eliminating boost altogether which I presume it isn't.
But the bypass on my supercharger is binary (in the case of Magnuson). You're either putting boost into the engine or your're not. There's no middle ground according to Mag. The bypass closes when manifold pressure is ZERO which is pretty near WOT. Great for a dragster. But not for a daily driver. Seriously, the compressor is turning all the time. Why not use the boost better and throughout the RPM range? Again, smarter people than me I'm sure have concluded that you need boost to get you from 0-60 (assuming that you've got your foot all the way to the floor) but you don't need boost when you get there. We'll they haven't' driven my jeep. They've driven corvettes or challengers which have one big difference. When they get to 60 mph and the supercharger goes to bypass the car is still being powered by a big motor. They started life as powerful HP to weight ratio vehicles. Superchargers take them from really fast to downright irresponsible.
But that's not us. We have jeeps. Big, square, heavy, full framed, solid axle, locking differential, large diameter tire jeeps. We started life under powered and overweight. I want boost at part throttle so when I speed up from 40 to 60 mph or 70-80 mph the truck accelerates with confidence. And I don't want to get that by opening up to WOT. There's no need for it. It just causes my auto trans to downshift. Heck, if I want to increase acceleration by lowering gears then I'd put 5.11's in the diffs and accelerate in third gear at around 5 thousand rpm's. I'm sure she'd pin me in the seat and I don't need a supercharger or turbo to do that.
So I've made a decision. For those of you who know that I'm struggling with the "lift to sift" issue I've found new PCM that I can install that will finally control my auto trans. I'm going to have it installed for me after the new year. Good new is it should meet my need for better shifting and all-time power. The catch is the PCM costs $25,500 to install and comes with a 6.4L hemi.
Ha! That certainly is one approach.Quote:
The catch is the PCM costs $25,500 to install and comes with a 6.4L hemi.
I'm liking the benefits of Turbo more and more, especially since my driving can take me into the Sierras for skiiing, so we're talking about a range from near sea level to 10K ft. Seems like the turbo would cope better. Would a supercharger just start to behave badly at altitude, or will you just get less boost?
The other side of this of course is that the install is definitely very involved compared to the SC, and being in CA I am concerned about passing smog tests later (my truck is new enough to not worry for a while, but it will happen eventually).