I personally changed the wastegate spring; non-issue. I will do a data log of a 2nd gear full acceleration and send it your way nonetheless.
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Alright Folks! Just received the stage 2 kit today!! Bad news though the shop cant get me in until late next week, and maybe not even then..At the latest, week after next..(the week of the 18th). I will be out of town all week next week and ill be dropping off the jeep at the shop Monday (11th). Hopefully they can dyno stage 1, install stage 2, dyno again while im out of town and document the dyno and install. At the very least if they cant do a video, ill have the dyno passes pre stage 2 and post. Keep you guys updated.
The spring was in a small bag that came with the stage II setup. Nothing was on the spring to indicate the PSI that it represented. I just followed the instructions and replaced it. I believe if someone goes directly to a State II from stock - the correct spring may be pre-installed. On my setup and yours, the parts required slight modification (i.e. spring).
Disregard everything i wrote about the 7Psi label on the spring. I read something different and thought it was the Wastegate spring bag. You are correct in that the spring does not indicate the PSI it represents. Sorry for the misinformation and confusion.
I think the 4.88 gears on Jesse's Girl could have significantly affected the dyno results, especially because it was run with stock 32" tires, and because of the nature of how a turbo works.
The overall gear ratio of 4th gear on that setup is close to 3rd gear with 3.73 gears, and is like something between 2nd and 3rd gear with 3.21 gears. This means that Jesse's Girl did not have as much load on the engine when run on the dyno as compared to Prodigy's dyno runs. This would lead to lower dyno numbers for 2 reasons:
1) The already-discussed issue of quicker acceleration on the dyno leading to lower dyno numbers because more torque is lost to accelerating the drive train more quickly.
2) Less load on the engine and quicker acceleration causes the turbo to spool up more slowly with respect to engine speed, so boost increases "later" in the rpm range, resulting in a lower peak torque that occurs higher up in the rpm range.
Additionally, common dyno practice is to use the transmission gear that is closest to a 1:1 ratio. 5th gear is a 1:1 ratio on the Wrangler, so it's possible that Prodigy's results are from a 5th gear dyno pull, meaning that Prodigy's dyno pull had even that much more load on the engine for slower acceleration, allowing the turbo to spool up at lower rpms, and giving up less torque to accelerating the drive train.
To get as close to Prodigy's conditions as possible, we need to find out what transmission gear they used for the dyno pull, then run Jesse's Girl one gear higher with stock tires. Even at one gear higher, Jesse's Girl will still be geared overall a little shorter (numerically higher), plus the driveshaft will be accelerating more quickly than the stock jeep (using up some of the torque), so I would still expect the numbers to be a bit lower than Prodigy's results.
Jeff: to be honest I don't believe in dynos what I believe is personal experience so my question is what do you feel about the gain and did u got what expected from the kit. Same questions to others (impression). I already ordered the kit (still waiting) but once I installed I will try to compare it with other cars plus other upgraded JK if possible. Gears affect how quick is your car , but in major view it dosent affect the overall performance.
My personal experience is all subjective, so it's not a valid basis for comparison. Butt dynos are much less trustworthy than real dynos. Starting around 3000 rpm, it goes fast, makes cool noises, and makes me smile. How fast is fast? Faster than stock is all I can tell you. Is it faster than RIPP or Magnuson? I have no idea. I haven't even seen one of their kits in person. Is it fast enough to make you smile? I wouldn't know.
That's why we use tools (dynos) to measure objective representations of performance (torque/power curves). If the tools are standardized and used consistently, then you get consistent and comparable results. We have seen inconsistent results at this point and are trying to figure out the cause inconsistency so it can be corrected to ensure that we have results that are consistent and comparable to other dyno results (stock, RIPP and Magnuson).
Hope you get a chance to compare with others legally in a track or down hills.
My butt dyno says Jesse's Girl is a rocket. But the 4.88s play into that. Did she feel fast? Yes. Was I going fast?... not as fast as it felt. I was merging onto a highway and I had the throttle nailed. It felt like I was on a roller coaster. But I was not blowing away traffic. Thats because the gearing was holding the overall speed back. (I think).
So is she fast? Yes, very fast.
Would she be faster with 4.10s? If we are talking about highway speeds, then yes. But the acceleration would suffer, and she might not feel as fast.
I have never heard of a 5th gear dyno.
Ive also been told by separate people that the gearing doesnt matter with a tumbler style dyno machine.
Im not an expert, these points, I have heard from different people. The power comes thru the drive train, and the rear wheels roll the tumbler. The tumbler dosent know what the gearing is, and im not sure the number of teeth in the ring alters the power from the driveshaft thru the wheels.
Maybe I can get someone from dynojet to tell us exactly.
The math might work out so that it doesn't really matter for N/A or supercharged engines, where there is a direct relationship between engine speed and torque output. But we're talking about a turbocharged engine here. It takes engine load and time to spool up a turbo. Just compare a 3rd and 4th gear run from Jesse's girl and you'll see how much of a difference the overall gear ratio can make.
This should be the story. Keep in mind all the results should be on the same dyno same configuration, same correction factor etc...
My thoughts are as follows.
1. Magnuson by design will deliver the highest off idle TQ gain
2. Magnuson will also have the lowest overall performance gain
3. Magnuson power will decline the longer it is ran due to heat soak and highest IAT
4. Ripp by design will have a linear power curve and will make peak HP only at max RPM
5. Ripp will make good power as the supercharger is large enough to move a high volume of air
7. Prodigy by design will deliver more power than ANY forced induction system on the market
8. Prodigy will make crazy power in the midrange where the Wrangler needs it the most Contrary to most dialogue
9. Prodigy will deliver sea level performance at higher elevation due to the use of a wastegate
10. Prodigy system can be upgraded giving it a win for HP per dollar
Attachment 957
Stage 1 is shipped with Red spring .4 bar
Stage 2 is White .5 bar
Read the bottom right of the image. I personally prefer the White and Green combination for Maximum fun.;)
Wes, why does your dyno chart show a loss of power, I understand the goal of midrange power, but I cannot understand why the prodigy power line dips under the stock line.
Also, can you give your position on axle gearing with dynos?
What tranny gear was prodigy's dyno done in?
When the vehicle is turbocharged, load is a huge factor. Graphing the lower RPM band is the most difficult. We ran the vehicle in 4th gear and slowed to the lowest point we could maintain a wide open throttle pull. So picture yourself in 4th gear and slowing down to like 2k and then give it wide open throttle. Not really ideal...
We use the dyno as a tuning device to hold the vehicle stationary. We then make adjustments while recording data from the vehicle and the dyno. This helps determine what adjustments are needed next. When its all done the street is where the fine tuning comes into play.
We used 4th gear for our pulls and also tested with 3rd gear. They were close enough where it didn't matter.
As for axle gearing on dynos, I personally have not seen this as a real issue. When I am taking the time to dyno a car I would start with a baseline, make the modification and retest to see the results of the modifications. If you are looking to compare something then the variables need to remain the same all the way down to how they are tested. What gear they are driven in, tire size, weather etc..
Gear ratio just changes how quickly the engine pulls through the RPM band. A gear change can deliver faster acceleration but will also get less fuel economy as it cruises at a higher rpm on the hwy. Turbochargers like load and I find ratios closer to stock work best. Over gearing may deliver adverse affects like poor fuel economy and surging on the highway.
Typically over gearing is done just to make up for the overall lack of power. If the Jeep performed great stock and you changed the tire size why wouldn't you just install the gear that puts you closest to stock? Choosing a different gear than this could give improved acceleration but would also change the rpm at cruise. The reason the performance went away is due to the weight of the tire and wheel combination. To get the performance back you will need more power.
Moving through the RPM band faster has an effect on power at the wheels; the significance of the loss is to be debated and could be a non-issue with regards to this level of power.
Higher numerical gear ratios are also used to increase crawl ratio off-road. That was one of my goals, especially with my manual trans. The higher the rpms when crawling..the smaller the the movements for a given throttle input. This also helps me into that midrange power band where my turbo shines.
Luckily I've had no highway surging of any kind; the highway driveability has been massively improved over stock.
Do you envision separate tunes for Stage 1, Stage 2, and eventually Stage 3 systems?
These two statements seem contradictory to me, when talking about a dyno pulls on a simple inertia dyno. Jesse's Girl definitely produced very different results in 3rd gear vs 4th gear.
Wes - are you using one of the much nicer dynos that can dynamically change its load to maintain a controlled/constant rate of acceleration during your dyno pulls? If yes, then we'll never reproduce those results on a simple inertia dyno.
I think i would have to make the comparison when i have the Jeep on the dyno. Doesn't sound possible to me. As i remember the pulls in 3rd were relatively the same in 3rd vs 4th. Certainly nothing that I recall that would make me choose one over the other. I think 3rd may be a better choice to see the dip in power that is in question.
DynoJet with WinPep 7
My boys at Power by the Hour are the best in the country. Check them out. Long time friends. http://www.pbhperformance.com
to talk to this point of 3rd vs. 4th gear, I cannot tell the difference when looking at the charts weather a dyno pull is 3rd gear or 4th gear unless you change the charts parameters to actual speed MPH, and not engine speed RPM.
Otherwise, you could end up laying 3rd gear runs over 4th gear runs and not know that its not apples to apples, in the RPM band, it looks like apple to apples.
Ross - I think you are talking about your 3rd and 4th gear stock dyno runs. I'm talking about Jessee's 3rd and 4th gear turbo dyno runs. The gear made a pretty big difference with the turbo. Want me to post a chart comparing them?
3rd gear definitely showed lower peak number than 4th. This was 100% expected by the shop rolling the dyno and by me. Again - its the idea that a dyno is most accurate where a 1:1 ratio is achieved. I didn't do the math to figure out what gear had my 1:1, I just assumed I should use 4th as was done previously.
My higher axle gearing would have skewed my numbers down vice the factory 4.10s in a given gear. The higher gearing changes the engine's rate of acceleration as a matter of fact. Faster engine acceleration equals lower bhp. Again - the effect of this is different for every dyno manufacturer and the way it does its math.
I'm feeling another dyno run is in my future.
Ok, here it is. Jessee's torque curve in both 3rd (blue) and 4th (red) gear:
Attachment 976
If the pattern continues, I bet a 5th gear pull (which due to 4.88 gears, would be similar to a 4th gear pull on stock gears/tires) would result in an even earlier and higher torque peak that has a shape more like Prodigy's results.
If i can get Prodigy to email me the install manual for the stage 2 upgrade, i can get my dyo passes in.. It was supposed to be today but the shop wouldnt begin without the Manufactures instruction manual. So i had to reschedule for tomorrow, anticipating ill get my hands on the install manual. I have an automatic with 5.13 37" mud grapplers. They will be doing dyno before the install and after the install. Again this is whether or not ill get the install instructions.
I had a conversation with wes today at length. A 5th gear dyno run would bring the truck to like 150 mph. Its out of the question.
4th gear is the closest to 1 to 1 and the axle gear ratio is a non factor.
Its not going to make 40 more hp if you run it in 5th.
Corrections:
5th gear is exactly a 1:1 ratio on the manual transmission.
5th gear with stock tires and 4.88 gears (the way Jessee put his jeep on the dyno) would max out at 122 mph at 6500 rpm.
5th gear with his 37 inch tires and 4.88 gears would max out at 141 mph.
For comparison:
4th gear with stock tires and 3.73 gears would max out at 128 mph.
4th gear with stock tires and 3.21 gears would max out at 148 mph.
Therefore:
Jessee's jeep with stock tires in 5th gear is similar to a stock jeep with 3.73 gears in 4th gear.
Jessee's jeep with his 37" tires in 5th gear is similar to a stock jeep with 3.21 gears in 4th gear.
Information calculated using: http://www.grimmjeeper.com/gears.html
Using 30.75" as the actual mounted diameter of stock tires and 35.5" as the actual mounted diameter of the 37" tires.
As Jessee's dyno results show, overall gear ratio does matter on that dyno, the way the dyno run was performed. The results are very different between 3rd and 4th gear. There is no way you can look at those results and conclude that the gear ratio is a non factor.
A difference in axle ratio causes a difference in overall gear ratio essentially just the same way a different transmission gear causes a difference in overal gear ratio. If axle ratio was a non factor, then transmission ratio would also be a non factor. If the overall gear ratio matters, then the entire combination of transmission gear, axle ratio, and tire size all matter.
I said Axle Gear is a non factor. Not transmission gear. The dyno connects to the cpu in the dash and uses the RPM of the engine to correct for the speed of the tumbler
Stock jeeps get dyno'd in 3rd gear because the stock tune hits the speed limiter in 4th.
Modded Jeeps get dyno'd in 4th, as it is closest to 1 to 1 ratio. I have never heard anywere of a jeep getting dyno'd in 5th gear.
Ive been at this a while, and have interviewed and worked with every power mod manufacturer. They all say the same thing.
Dynojet both drum speed and engine speed are measured and used to take out any effects of gear torque multiplication.
Ive been searching for about 40 min now, and cannot find a clear final answer about the inner working of the dynojet. Ive read arguments from both sides of this in other forums and there is no clear post that would settle this.
I will call dynojet tomorow and make them email me a response I can post.
I didn't misquote you (that wan't a quote where I said "overall gear ratio"). I was trying to bring attention to the fact that it is the overall gear ratio that caused the difference in Jessees results. Transmission ratio and axle ratio both contribute to overall gear ratio.
It doesn't matter whether the difference in gear ratio is in the transmission or in the axle. A difference in gear ratio is a difference in gear ratio. If one matters, then the other matters. There's no way around it. The overall gear ratio is the transmission gear ratio multiplied by the axle gear ratio. One is not not inherently more significant than the other just because of its physical location. If you agree that transmission ratio is a factor, then you are also agreeing that axle ratio is a factor.
4th gear is a 1.25:1 ratio.
5th gear is a 1:1 ratio.
How is 4th gear "closest to 1 to 1 ratio" if 5th gear is EXACTLY 1 to 1?
The difference between 4th and 5th gear is 25%. The difference between 3.21 axle and 4.88 axle is 52%. The difference between 3.73 axle and 4.88 axle is 30%. The difference between Jessee's axle ratio and stock axle ratios is MORE significant than the difference between 4th and 5th gear!
AGAIN: This is is a special situation to turbos only, because it's related to the amount of load on the engine and the duration of the dyno pull allowing the turbo to spool up. This is not about the typical factor of drivetrain rotational inertia. I agree that the axle ratio (and transmission gear) would have minimal effect on a naturally aspirated or supercharged engine, because they do not depend on engine load to produce power.
The turbo needs engine load and time to spool up. The amount of load on the engine on a simple inertia dyno is primarily directly proportional to the overall gear ratio from the engine to the dyno drum (including transmission gear ratio, axle gear ratio, AND tire size). It's the overall ratio between engine speed and "road speed" that matters here.
This also all only matters on an acceleration sweep dyno pull (which is the only type that an inertia dyno can perform). If we could get steady state results on a load bearing dyno, then we wouldn't have to worry about any of this (tire size/weight, gear ratios, etc).
We already have a test that shows that gear ratio matters hugely on the dyno that Jessee used. His dyno results clearly fit the my explanation of the turbo spooling up more slowly with respect to engine speed when using gearing that creates less load on the engine.
All the people that have all told you that axle ratio doesn't matter... was it clearly being discussed in the context of a turbocharged vehicle on an inertia dyno (or sweep test on a load dyno)? it's not a matter of either me being right or them being right. Context is key. Their statements are true in many contexts. Their statements are false in this specific context of a turbocharged vehicle on an inertia dyno (or in a sweep test on a load dyno).
It will depend on exactly which model of dynojet dyno. Some are inertia dynos, others are load bearing dynos.
Simple inertia dynos are only capable of acceleration sweep tests, and the load is simpy the mass of the dyno drum. This type of dyno is 100% guaranteed to have the problems I'm trying to describe with significantly different results with a turbocharged vehicle with different transmission and/or axle ratios. Rotational inertia of the drivetrain/tires/etc also affects the readings on these dynos, 100% guaranteed.
Load bearing dynos are capable of performing steady state dyno pulls, where it holds the engine steady at full throttle and records the amount of load (torque) was required to hold the engine at a steady rpm (rinse and repeat for many different engine speeds, and you get data points to form a cull rpm range dyno chart). This would give consistent results no matter what transmission gear, axle ratio, or tire size was used, because there is no torque lost to accelerating those components (so therefore no differences in the amount of torque lost to accelerating different configurations of those components), and the turbo lag would not be an issue either because the turbo would be allow to spool up at each rpm point and reach equilibrium before the measurement is taken.
Load bearing dynos can also perform acceleration sweep tests, but can be configured to perform the sweep in different ways. This is even more complicated than a sweep test on an inertia dyno, because at least an inertia dyno can only operate in one mode. The results of a sweep test on a load dyno can be affected by a combination of gear ratios, tire size/weight, AND how the dyno operator configured the dyno to operate (slower sweep with more load? faster sweep with less load? constant load? varying load to achieve constant rate of acceleration?).
Yes, it's a big mess :)
So there's a catch 22 here.
A steady state dyno chart is the only way to get guaranteed consistent and comparable dyno results (regardless of gears, tires, etc).
But a steady state dyno chart is arguably not "realistic", because we use the torque/power of our engines primarily to ACCELERATE... not to maintain steady state speed. A tiny fraction of the peak power is actually required to maintain steady speed. A steady state dyno chart will show the highest results of all, but you will never experience that amount of torque/power while accelerating on the street.
When accelerating on the street, some of that torque/power gets used up to accelerate the drivetrain and wheels. The faster you accelerate (i.e., lower transmission gear), the more of the torque/power is lost to accelerating the drivetrain and wheels.
With a turbo, the effect is compounded by the turbo spooling more slowly when under less load in lower transmission gears. Or you can look at it from the other direction and be happy that with higher transmission gears, the turbo has the advantage of spooling up more under higher load to produce some more power, making up for some of the loss of torque multiplication from upshifting to a higher gear :)
(I've actually noticed that compared to my expectations based on how 1st and 2nd gear feel, 3rd pulls VERY strong all the way up to redline, without ever feeling like it's losing steam due to increasing air resistance.)
So what people really care about is a representation of how the vehicle will accelerate on the street. It makes sense that the best dyno test would be one that mimics acceleration on the street.
Load bearing dynos can be configured to perform sweep tests that simulate actual acceleration on the street, by dynamically adjusting the load of the dyno throughout the test to simulate both the load of the weight of the vehicle, and the load of air resistance (which increases with speed, proportional to the square of speed). This only works well if the dyno is accurately configured with the vehicle's weight and aerodynamic drag constant (drag area). I know Mustang dynos work this way. I'm not sure if the load bearing Dynojet dynos can do this. Even if you configure the dyno accurately, you still have problems. Which gear do you use? Do you simulate a fast 1st gear acceleration, which will give the lowest results (due to larger rotational inertia losses from the drivetrain, and slower spooling turbo with respect to engine speed), but most accurately represent the most acceleration you'll ever feel from the vehicle? Do you simulate acceleration the highest gear that can reach the rev limiter, which would give the highest results (least rotational inertia loss, turbo spooled more fully at lower rpms), but not accurately represent the power you will use in everyday driving? Or do you go with some middle gear for a balance of impressive numbers and realistic representation of what you'll experience most often on the road? Different jeeps with different tires and axle ratios would also produce different results on this type of dyno pull, which would accurately reflect their affect on real world driving performance.
The Dynojet response is at the top, my question is at the bottom.
Ross,
The reading (as you call it) will most likely be different because the work performed by the Jeep will different with different rear gears.
Even without changing the rear gear, you can make a run in 3rd and another in 4th and so on and they will show different HP.
But think about what is going on here---
the computer is monitoring the acceleration of the dyno drum, it has no idea what type of vehicle is on it or what gear it is in.
Measuring Rear Wheel HP where the tire touches the drum means any change made before the drum has the potential to change the RWHP .
Above is some theory to ponder.
Please don’t believe everything you read in forums.
Thanks,
Bill
From: ross@jeeplab.com [mailto:ross@jeeplab.com]
Sent: Monday, August 11, 2014 7:59 PM
To: dynotech@dynojet.com
Subject: Dynamometer Tech. Inquiry
Entered on: http://www.dynojet.com/Contact/Dynojet-sales.aspx
Submitted On: 8/11/2014 10:58:33 PM
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Regarding: Model 224x
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Name: ross
Email: ross@jeeplab.com
Country: United States
Comments: Im from JeepLab.com and we are dyno testing a new turbo Jeep Wrangler with a dynojet. The argument in the forum right now is weather or not the axle gear ratio will alter the dynojet's reading. Will 3.21 gearing give a different dyno reading than 4.88 gearing assuming all other variables are the same? Thank you!
Soooooooooooooooo where do we go from here?
NOLA, Did you ever get the instructions?
We will need the stats on the NOLA jeep to compare to JG for a point of reference?
Nope did not get the instruction manual. I'm out of town until Sunday.. I dropped my rig off Tuesday morning without the instruction manual, and emailed Dan at prodigy .. Told him I had dropped off the jeep and the shop was waiting for his instructions.. Haven't heard from the shop or prodigy. So I am assuming everything is going well. I will update whenever I get additional info.