resonator Question

[moparguy96]

thanks for your input. but are you guys running a strait pipe from the cat back. or did you replace the res with a high performance one i know where i can get one installed for unde a 100$. my hole goal is to try to get up to almost 300hp. i already have a nice dual tiped strait flow muffluer that i cant pronounce the name of. and i think i did what every one was saying i removed the hose from the filter to the intake and took out a smaller plastic restrictor. i also have a few minor extior mods. so all the help i can get for a low budget is a great help. thanks

[Marlin]

I hope you plan on a transmission rebuild in there, cos I was planning on a nitrous kit and was basically told to save an extra $2400 for a new trans after it rips itself apart from the power. Last trip to the dyno showed me with 240hp running on 89 octane. Don't even bother keeping a resonator let alone a high performance one. The rear or the exhaust system is a LARGE muffler under the rear seat, and a smaller resonator under the trunk. I had both removed and replaced with one muffler, a $17 off http://www.wrenchhead.com/ Thrush California Boss Turbo muffler... Best $17 I ever spent...Cost $100 to have everything sawed off, the pipes bent, and a chrome tip installed.

Sam

[Fluid]

Marlin, a question NOT a flame. How have you determined that you're actually getting 240 engine horsepower from a chassis dyno? With the 'normal' 25% loss through the LH drivetrain, a 240 hp reading at the wheels would require 320 at the flywheel. Conversely, 240 at the crank would net around 180 at the wheels. There are other ways to guess at crank hp.

Too, what dyno was used? The most repeatable are the DynoJet inertial types - the waterbrake dynos are notoriously inaccurate. Fortunatley, most modern shops seem to have the DJs. Thanks.

[moparguy96]

i work for a car dealership and it so happend that we have a dynojet dyno and it showed me at 240hp. but i dont really know if that was at the wheels or at the flywheel i know that the 3.5 puts out 231 stock and pretty much as high performance as it can get on a low budget. also i have a friend that is working on rebuilding a stock trans that i got from a bone yard and he is giving me a pretty reasonable price. but i dont wont to run nitrious.but any other tips can help.

[GR8WHT]

Moparguy96, what kind of mods and what year 3.5L are you talking here?

[Fluid]

From his handle I'd guess he has a '96. ;^)

A DynoJet only reads front wheel horsepower; it cannot know the engine power at the flywheel since this is dependent on the driveline efficiency. Typically, cars lose from 20 to 25% between the flywheel and the ground. If the dyno actually showed 240 HP, then the power at the flywheel would be between 300 and 320 - neither is likely. I just was wondering what the dyno actually showed, and how the 240 HP was determined. And, are Marlin and moparguy96 one and the same person? Both say they have dyno'd 240 HP.....?

While the 3.5 claimed 213 HP, in fact the compression was reduced from 1995 on and the power dropped, even though the factory-stated power remained the same. Thanks.

[Marlin]

Nah we're not the same guy, and the dyno was at a shop down in Nyack, NY... I also know that to get 240hp at the wheels I'd have to get 300-320hp at the flywheel, I've no clue what type it was, but he brought up a menu where he could compare what the car is stock, to where it is now, etc... I believe it said 240 at the flywheel... Either way, it's a damn quick car and it has suprised its share of "sporty" coupes.

Sam

[Fluid]

Thanks Marlin...I did know that you weren't "the same guy" from the addresses, but the coincidence was interesting. Should have used a smiley.

I've often wodered why the current LH cars with the Gen2 3.5 are so soft off the line - it's difficult to break traction on many surfaces, while Gen1 LH cars report this is easy to do. My best answer is the computer. It is well accepted that the transaxle is the weak link in the LH driveline, and the scuttlebutt has it that DC "fixed" it ca. 1998. Apparently the current software retards/leans out the engine at start-off and at the shift points to shield the transaxle from shock loads. Good for transaxle life, not so good for low-end performance. This is from magazine techs, so it is not irrefutable. :P

Marlin, is there much interior resonance with your current exhaust setup? Pleased with the sound? Thanks again.

Jay T

[moparguy96]

i have a 96 interpid. I have a full free air intake no resonator and a strait flow muffler. i have also replaced all of my old injectors i have a set of bosh quad platinium plugs now i am looking into having my throttle body's rebuilt to see if holley makes any up grade kits.

[Marlin]

when did those bosch come out for this car? i went in like 2 months ago and they didn't make them yet...

sam

[GR8WHT]

No Gen 1 3.5L is producing 240 HP at the wheels. Stock is 215 HP at the flywheel.
The mods listed would net, maybe, at best a 10 to 20hp increase over stock.

Nitrous or forced induction would be required to get 240HP at the wheels on a gen 1.

The numbers just don't add up

The dyno must be way out of alignment.