loss of power???? installed new clutch and exhaust?

[zr-1assassin]

hi all, i just had the new clutch installed(acdelco) and put on some magnaflows and had the resonator removed. for some reason it feels like i lost some power, especialy in the lower rpm's. whats going on here??? do i need to adjust the fuel/air because of the exhaust change or do you think its something to do with the clutch? had them done about a week apart from one another and i noticed it after the clutch was done. has anyone heard of loosing power from a new clutch??? it just doesn't feel as strong as before.used to roast tires in 1st,2nd and little in third..... now barks in first and thats about it. anybody have any of this s%$$t happen to them?

[Peaven]

hi all, i just had the new clutch installed(acdelco) and put on some magnaflows and had the resonator removed. for some reason it feels like i lost some power, especialy in the lower rpm's. whats going on here??? do i need to adjust the fuel/air because of the exhaust change or do you think its something to do with the clutch? had them done about a week apart from one another and i noticed it after the clutch was done. has anyone heard of loosing power from a new clutch??? it just doesn't feel as strong as before.used to roast tires in 1st,2nd and little in third..... now barks in first and thats about it. anybody have any of this s%$$t happen to them?

Sounds like your secondaries aren't opening up....have you pulled any codes yet? Anything else like the SES light coming on, etc?

[zr-1assassin]

hi peaven, no lights on at all. the secondaries are opening above the 3500 mark and i can feel a differance with the power key on/off. seems to be in the lower rpm's where i notice it most. it runs strong in the 3500-7000 range.

[Jeffvette]

If you don't have everything lined up properly, it could be causing a binding issue.

[jonszr1]

another thought, did you go to 3 in / it could be an issue of the exhaust being too big . I ntried 3 in with just headers and lost low end tq. Iin fact i have made the most power with my new set up 3in to a ultra flow x pipe muffler and 2/12in out of that to flowmaster mufflers . if your car is basicly stk I would bet that the exhaust chg is causing . unless you are hearing noises from the clutch area . if it were binding you would proably feel a much heaver peddle . i know as I had that problem and it squelled like a stuck pig until the zf doc fixed it. jmho

[zr-1assassin]

ya, i was thinking it may have something to do with the back pressure too:icon_scra. it also now backfires a little, that won't hurt anything will it? it is the low-end torq. that has been effected so maybe it is the muffs. they are staight thru magnaflow mufflers with no back pressure. what should i do?

[jonszr1]

if ya think about it a little . If you are going to do a little drag racing the car will be easier to launch with this exhaust . the loss of tq is proably max 20 . It just depends on what you want to do with her . is it loud now? do you like it that way. Another mod to think about would be 410 gears . now that get your tq back right now. is your car stk except exhaust ? you might want to get ahold of the guy that tuned ,my car is is one of the best and could burn a new prom for you. here bis his e mail tell him that guy from lone pine sent ya .corey@hendersonperformance.com . he sure did a great job on my car. he also is a zr1 nut and has a very quick 368 91 zr1 as his personal ride. hope this helps .but talk to him before ya change anything he wont steer you wrong , promise

[tomtom72]

FWIW, the bigger exhaust diameter + different mufflers I'm sure has cost something on the low end. But I would be concerned about the fact that after the clutch was done and before the exhaust work (do I have that right?) you felt a difference.

I'm with Jeff. I would go over to zfdoc.com and look in the Q & A section about C-beam alignment. Heck, Bill is a stand up guy and always answers Q's if you e-mail him. I would do some checking up on the C-beam alignment just to be sure. JMHO.

:cheers:
Tom

[zr-1assassin]

hi guys, thanks for all the replies! the exhaust sound to me is worth a little loss (now has the rummmmble)but i always thought with releaving back pressure you would gain power? and whats with the back fireing? i dont know! and ballpark whats a set of 410 gears run for these beast? that would help the low-end problem! mine is all stock(unfortunatly) besides the exhaust. but i'v only had it for a few months so give me time and it wont be! i'm going to check into a prom, is there anyone around missouri for this or do they just set you up site-unseen? the clutch is good and tight and no noise comming from it so i do think(hope) its the exhaust....its not to bad, i can live with it for now i guess.

[tccrab]

hi guys, thanks for all the replies! the exhaust sound to me is worth a little loss (now has the rummmmble)but i always thought with releaving back pressure you would gain power? and whats with the back fireing? i dont know! and ballpark whats a set of 410 gears run for these beast? that would help the low-end problem! mine is all stock(unfortunatly) besides the exhaust. but i'v only had it for a few months so give me time and it wont be! i'm going to check into a prom, is there anyone around missouri for this or do they just set you up site-unseen? the clutch is good and tight and no noise comming from it so i do think(hope) its the exhaust....its not to bad, i can live with it for now i guess.

Gears are ~$300, the best are the Viper gears. Setup and installation will run you another $600-700. Have them installed by a pro, it's not a home job unless you *really*really*really* know what you're doing.
Prom. Call Marc Haibeck, http://www.zr1specialist.com , his are the best.
He's actually not far from you.
He'll do your gears too.

TomC
'90ZR1 #792
Honorary Pirate

[zr-1assassin]

hey tccrab, thanks for the info! that will be my next mod.... as soon as the wife alocates funds my way. did you get the gear change in yours? how big of a differance can i expect? did you mean gears out of a dodge viper or is that a brand name? i'm going to the website you pointed out right now.... thanks again!

[jonszr1]

they are Viper gears they are thicker i believe to handle the extra tq. the 410s will make a big diff in the pants:mrgreen: plus this face

[JMKZR1-94]

Hi guys, interesting discussion about loss of power. What (how much) power can i expect from my ZR (recently bought a ZR-94). You where talking about "rosting tires" in 1,2 and maybe third gear??? My ZR does not "rost tires" in 2 and third gear! It,s stock besides no cats and corsa exhaust. Another thing i noticed is that my ZR responds (gaining power) very much when it,s cold outside.

[zr-1assassin]

hi there, the flag that shot up at me was the exhaust! thats when i lost some power. im starting to think aftermarket exhaust is not a good thing for the z. maybe it just needs a little back-preasure or something. because before the exhaust.....roast tires, and yes even in third!:D we need more acounts of this to make sure. anyone else out there notice the power loss after exhaust????

[jonszr1]

the thing is when one is roasting tires you ain't goin anywhere you want to haze the tires just bearly spinning. from .my mod experience. it stk331.9 exhaust (flowmaster) headers (jeal) 372 inc in that rc inj fidanza flywheel ceramic disc clutch. ported inj and plenum and chassis dyno prom burnt 409.9. i dont think one gets more powe with 3 in till you get to 430 rwhp . my flomaster is the 21/2 kit they sell for the z. the 410s that I have i believe is the frymaster part of the combo but i would do 373 if i had it to do over . iy would mmmake life at the strip alot easier:mrgreen: hope this helps

[zr-1assassin]

interesting? why would you go 373's instead of the 410's? im getting ready to install 410 and would like any feedback from actual experience i can get before i do it!

[95ZR1#418]

If you have a backfire problem then you best follow the flow sheet in the shop manual. My guess is you have blown a vacuum line with the backfires, under the plenum, check the MAP first. Do the vacuum pump test, an easy check to confirm anything leaking under the plenum.

I take it you don't have headers? I know with headers you may get backfiring unless you get a new upgraded chip from Marc Haibeck which eliminates the backfires.

[jonszr1]

the reason id rather have 373 gears is launching the car a the strip. it would be an easier hook up. i know of one guy that has a 385 and went to 373 and the car went faster at the strip.. just my thoughts to each thieir own . any one that wants 410s that has 373 ill entertain a trade. or if someone has 373s allready set up they want to sell pm me

[zr-1assassin]

i may be interested in getting the 410's if you sell them, let me know. thanks

[zr-1assassin]

If you have a backfire problem then you best follow the flow sheet in the shop manual. My guess is you have blown a vacuum line with the backfires, under the plenum, check the MAP first. Do the vacuum pump test, an easy check to confirm anything leaking under the plenum.

I take it you don't have headers? I know with headers you may get backfiring unless you get a new upgraded chip from Marc Haibeck which eliminates the backfires.whats the test process for the vacume leak? i dont have headers, just removed the resonator and free flow magnaflow mufflers. it does backfire if i rev it up...sometimes.

[ArcticZR1]

I'm getting worried now...I have my B&B w/ X pipe coming this week. Is it going to be bad hooking it straight up to a stock car for now? This will be the first mod my 91' has seen...:icon_scra

[jonszr1]

if its like the flowmaster was ,it will be a piece of cake. you might want to call b&b and ask them for any hints or things they feel you might need to put their system on

[cward]

Interesting thread. I thought I would throw in my opinion. The first thing I did to #364 was headers thru stock exhaust, no cats. It gained hp and torque. Then put on ported plenum and IH. Gains in both. Then Power Effects mufflers thru stock resonators. A little gain. Then removed resonators and put in X-pipe. No gain in torque and may have lost a couple of lbs. Then changed plenum for one that was ported about as much as you can without cutting. Also custom 3" SS exhaust with X-pipe and nothing else. About as free flow as you can get. Torque stayed about the same or might have lost a couple of lbs. Rwhp went up about 20 hp. At that point, my torque was right around 350 lbs and rwhp about 392.

When you said it backfired a little, I would check vaccum lines etc. Should not backfire at all. And I would not worry about putting on B&B with X. More (a little) hp and probably same torque.

About roasting tires in 2 and 3 gears. That should not happen with stock or even lightly mod Z. Some spin in 2nd and maybe a squeek in 3rd but no roasting. If that happens, get better tires. :-) Even with 4.10 gears. In fact, even when I sprayed, and was probably putting out about 600 rwhp and close to that in torque, I would not roast 3rd. I could in 2nd but had to try, and that is not the goal so just a little technique and good tires made everything OK. I know of one person that went from 4.10 to 3.73 but that was for running standing mile. He ran out of gear before the end of the mile, over 180, not for street or strip driving.

Curtis

[jonszr1]

opps hope ya all don't think I can roast my tires in second or third . with the 410s and goodyear d3-3s first gear is a joke. that is why I personally would like 373s . my left foot seem to have a mind of its own, it just for some reason gets excited and goes straight to the floor:mrgreen: .so i figured with 373s if figured I wouldn't have to try to retrain that 54yr old foot:mrgreen:

[zr-1assassin]

I'm getting worried now...I have my B&B w/ X pipe coming this week. Is it going to be bad hooking it straight up to a stock car for now? This will be the first mod my 91' has seen...:icon_scrai think you may lose a little low end, but who knows maybe it was just mine(my luck), even if it does you will get it back in the future im sure. let me know if it does.

[ArcticZR1]

With my stock ZR1 I can get a pretty good bark in 2nd...but thats dropping it over 3k with the secondaries on...when those kick in cool sh$& happens! Quiet in 3rd though. I envy you guys who are up in the 400hp+ range...I just don't know how you keep tires on the car...I couldn't!:mrgreen:

[JMKZR1-94]

Hi Guy,s

First:
I was thinking of replacing rear-gear to 4.10 and found one at ECKLERS. The thing is that, first they told me that it has to be a Dana 46 or 48 but later i got a mail from them telling me that the rebuilt Dana 44 that they offer is working for my 94 Zr-1...??

Second:
Can You guy,s give me some hints of where to find nice rims and tires, maybe 18" or 19" with the right offset and so on.....

Looking forward to here from You
PS, The snow is just about to leave Sweden...=D>

[cuisinartvette]

I doubt you lost that much power from the exhaust. having mufflers that breathe and minimizing backpressure...good.
Too big a pipe diameter you lose velocity and scavenging..Not good, but wont make the car a total pig either. Did your 02 sensor get baged up during your exhaust change?
Any dyno nearby where you can have the A/F ratio checked via a sniffer in the pipe?

I have dual 3's on mine and it may be overkill..even if I got to keep it and do a top end port job Im betting 2.5 in pipes are fine. It may flow more air, but its still a small motor.