Pettit Super Charger Owners
07-19-2010, 06:33 PM
#7351
Originally Posted by WingleBeast
;3640567 the pettit is NOT a plug and play setup, there are some large deficiency, and unfortunetly they do not receive the support the Greddy ones do, however they are less catastrophic.
Both of my Pettit kits were close to the plug and play ideal; I lost the first one to the fuel line quick connect failing and burning that one to the ground, but up to then was music to the ears and the ***. The second one probably runs even better. Asking 300 hp and long term happiness from a motor that displaces about as much as a 40oz bottle of bad beer is fun; asking it to give you 400 hp and survive is, IMHO, lunacy. Of course, if lunacy is your thing, then you'll have fun.
Pettit kits run a relatively mild 5-8 lbs of boost, survivable for a small 6 "cylinder" two stroke. Start running in the double digits of boost and whatever FI system is used, no matter how good your tuning is, that kind of stress is going to exploit any weaknesses in the stock motor.
Pick your FI, turbo or S/C; if you want a daily driver, stick with the lower boost. If you want a grenade, just make sure you know how to swap motors. And yes, MM doesn't particularly like Pettit systems, but in all honesty, other than some good lesbian ****, I really haven't been able to figure out what he really does like. Probably just beyond my ability to understand.
Last edited by zenrx8; 07-19-2010 at 06:37 PM.
07-19-2010, 07:14 PM
#7354
07-19-2010, 07:20 PM
#7355
Air is air. It just happens that a supercharger is one of the less efficient ways to get it into a Renesis and the Pettit system was - out of the box - one of the most poorly cobbled-together ways of implementing a supercharger.
07-19-2010, 07:22 PM
#7356
I divide by zero
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07-19-2010, 08:04 PM
#7359
Moreover, after several years of addressing and correcting the shortcomings of the Pettit kit, no one is more appropriately equipped on this forum to discuss the kit than myself and BHR.
07-19-2010, 08:33 PM
#7361
Correct me if I'm wrong:
Lower PSI for a given horsepower = better efficiency. For example, if kit A achieves 300 rwhp at 9 PSI and kit B achieves 300 rwhp at 12 PSI then kit A is designated more effective.
So in theory, if the owner wanted the "safest" 300 rwhp out of the car they should buy the kit that gets them to 300 rwhp using the lowest PSI levels?
Obviously there are other things that come into play but could that not be used as a general rule of thumb?
Lower PSI for a given horsepower = better efficiency. For example, if kit A achieves 300 rwhp at 9 PSI and kit B achieves 300 rwhp at 12 PSI then kit A is designated more effective.
So in theory, if the owner wanted the "safest" 300 rwhp out of the car they should buy the kit that gets them to 300 rwhp using the lowest PSI levels?
Obviously there are other things that come into play but could that not be used as a general rule of thumb?
Last edited by Red Rex; 07-19-2010 at 08:36 PM.
07-19-2010, 08:38 PM
#7362
In other words; if two compressors move 330 gms./sec. but one does it at 6 PSI and the other at 8 PSI, the 8 PSI version will be less efficient and have higher outlet temps, thusly making tuning a challenge (to an extent).
Measured at the manifold, those same two compressors will move the same amount of air but one incoming charge will be hotter than the other. Whether the intake temperature delta between the two compressors makes a difference is up to the man with the money.
Then, as mass-airflow relates to RPM and compressor efficiency, you have different driving characteristics between the various offerings.
Last edited by Charles R. Hill; 07-19-2010 at 08:45 PM.
07-19-2010, 08:46 PM
#7363
07-19-2010, 09:14 PM
#7364
Lower PSI for a given airflow mass, depending on where you choose to measure said PSI, as in compressor outlet pressure or manifold pressure.
In other words; if two compressors move 330 gms./sec. but one does it at 6 PSI and the other at 8 PSI, the 8 PSI version will be less efficient and have higher outlet temps, thusly making tuning a challenge (to an extent).
Measured at the manifold, those same two compressors will move the same amount of air but one incoming charge will be hotter than the other. Whether the intake temperature delta between the two compressors makes a difference is up to the man with the money.
Then, as mass-airflow relates to RPM and compressor efficiency, you have different driving characteristics between the various offerings.
In other words; if two compressors move 330 gms./sec. but one does it at 6 PSI and the other at 8 PSI, the 8 PSI version will be less efficient and have higher outlet temps, thusly making tuning a challenge (to an extent).
Measured at the manifold, those same two compressors will move the same amount of air but one incoming charge will be hotter than the other. Whether the intake temperature delta between the two compressors makes a difference is up to the man with the money.
Then, as mass-airflow relates to RPM and compressor efficiency, you have different driving characteristics between the various offerings.
07-19-2010, 09:16 PM
#7365
07-19-2010, 09:17 PM
#7366
HAVOC
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it is more of a slow buildup. but you already know that, i just worded it poorly trying to prove a point to someone who jumped on one bandwagon without checking out the other.
I'm not exactly sure what "plug and play" means; if it means once it's installed, you can drive happily away and never have to check to see if you're building trims or if your AFRs are proper under this load or that, then nothing is "plug and play".
Both of my Pettit kits were close to the plug and play ideal
Both of my Pettit kits were close to the plug and play ideal
07-19-2010, 09:20 PM
#7367
07-20-2010, 11:08 AM
#7374
Ok then.
1st of all the Pettit kit no longer comes with the abs plastic bypass valve- its a aluminum o ringed sealed valve--very nice.
2nd overtighten belt---who says? My belt is not any tighter than any other belt. I use the 90 degree twist rule. I have no identifiable signs of slipage at 7.5--8K. ( I have increased my redline a little).
By the way I dont think MM is a vendor listed? Nor BHR?
The Pettit kit is a good kit---not perfect but no kit is for all applications.
We get good results power wise and we dont have any equipment failures other than the a/w intercooler pump may need replacing after a few years. I havent heard of anything else?. The blower is guranteed for 100K miles. The kit is backed by a reputable company that has been in business for years and can supply everything you need for your engine for whatever you want to do.
I dont know of any other kit out there that is selling and delivering like this one.
Perfect---no.
Good ---yes
OD
1st of all the Pettit kit no longer comes with the abs plastic bypass valve- its a aluminum o ringed sealed valve--very nice.
2nd overtighten belt---who says? My belt is not any tighter than any other belt. I use the 90 degree twist rule. I have no identifiable signs of slipage at 7.5--8K. ( I have increased my redline a little).
By the way I dont think MM is a vendor listed? Nor BHR?
The Pettit kit is a good kit---not perfect but no kit is for all applications.
We get good results power wise and we dont have any equipment failures other than the a/w intercooler pump may need replacing after a few years. I havent heard of anything else?. The blower is guranteed for 100K miles. The kit is backed by a reputable company that has been in business for years and can supply everything you need for your engine for whatever you want to do.
I dont know of any other kit out there that is selling and delivering like this one.
Perfect---no.
Good ---yes
OD
07-20-2010, 11:16 AM
#7375
Tailgaters beware
Without FI our motor makes increasing power up to around 8800 hp(which I'm going by my own dyno testing), with turbo's I always see everyone has to let off around 7800-8000 because the power starts falling off. From what I've read, it's something to do with the exhaust ports not being able to flow enough for the turbo to keep working properly. (Being vague)
I don't see this problem with the Pettit. The dyno's look similar to a stock dyno, but on a higher HP scale. That to me shows that the Pettit kind of works with the motor, which gives me the idea that it has less of a chance of breaking seals.
I am not any kind of expert on our cars, but I am just going by reading about blown motors for the 4.5 years of owning my car. I don't read a lot of Pettit charged blown motors, but I continue to read about turbo's blown all around the world every week. This could also be because there are probably a lot more turbo'd RX-8's out there since the Greddy is $3800, and the Pettit is $6200.
I would actually rather have a turbo since I have owned a few turbo'd cars, and have always loved the torque and the power band with or without lag, I really don't prefer the sound of the SC or the way the power feels. I have driven a few Lightnings and 2003 Cobras and actually chose my RX-8 over an 04 Lightning after test driving both.
To me it just seems like without a rebuild the SC might be safer.
I think the turbo's end up being faster, from 1/4 mile times I've seen. Which I do like, but I am trying to measure reliability of one setup over the other for someone that is not an experienced tuner.
That's one of the funniest things I've read in a long time...
Last edited by Rocketman1976; 07-20-2010 at 11:54 AM.