low traps, slow ets after pi swap

KJ Hoppus · Jun 13, 2004

MyETs - Compare Runs

60'
2.092 2.112 2.172 2.192 2.176 2.163 2.094 2.191 2.215 2.151 2.174 2.136

1/8 mile
9.245 9.374 9.488 9.523 9.385 9.415 9.297 9.478 9.518 9.344 9.439 9.395

1/8 mile trap
76.390 75.453 74.830 75.377 75.593 75.525 76.009 75.044 75.018 75.660 75.492 75.417

1/4 mile
14.370 14.570 14.700 14.735 14.554 14.605 14.465 14.678 14.725 14.585 14.635 14.599

1/4 mile trap
96.802 95.321 94.829 94.982 95.511 95.497 95.848 95.070 94.873 82.504 95.282 94.766

what do you guys think. i was trapping 95mph and running 14.5 all day. before my swap i was trapping 98mph and 14.3s.

during the swap i added: pi heads, intake, arp studs, ported plenum, ported 70mm tb, FRPP shorty headers, 160*, shift kit, ac delete.

crazynorwegian · Jun 13, 2004

I would get the car dyno tuned

stangman · Jun 13, 2004

dude, that was the most confusing post evar.

but i would say weather was to blame more than anything, if i had to guess. because with that stuff, there is no way you are slower.

KJ Hoppus · Jun 13, 2004

c2see21 said:
dude, that was the most confusing post evar.

but i would say weather was to blame more than anything, if i had to guess. because with that stuff, there is no way you are slower.

its not the weather, same track, same time off year, same temps. the thing is i think there is something wrong with my car. i did a compression test already, all the cylinders were around 190 to 200.

KJ Hoppus · Jun 13, 2004

crazynorwegian said:
I would get the car dyno tuned

i dont think tune is my problem.

KJ Hoppus · Jun 13, 2004

anyone else have any ideas?

Red2000GT · Jun 13, 2004

KJ Hoppus said:
its not the weather, same track, same time off year, same temps. the thing is i think there is something wrong with my car. i did a compression test already, all the cylinders were around 190 to 200.

190-200 is awesome compression,there's definately no problem there. How is the car running otherwise? Is it rich(burbs or pops lots when you let off the gas at higher rpms)? I would check EVERY vaccuum line and injector plug and spark plug wire. Also make sure your coil packs are functioning properly and check to make sure the engine ground is re-attached to the body.(it's down low on the driver's side front of the engine,by the oil filter) I've found it's usually something minor that causes problems after major engine work. Also get that 160 thermostat out of there,there's no performance gain to be had by using it,the engine adds timing AND fattens itself up when cold,negating each other,you're just lowering your gas mileage.

bierbelly · Jun 13, 2004

Weird. I was running about the same after my headswap, but I was running street tires. One thing I did notice was a definite loss in power after having some Flowmasters welded into my stock system. Go figure. Confirmed by dyno numbers. Needless to say, I'm not impressed by Flowmaster products, but some suggested that the catback system probably works better than the muffs alone. Who knows? What are you running the T/A at? You're in CA, so are you limited to 91 octane? Before I decided to sell my '98 GT (also Rio Red, btw...good choice), my next step was going to be 4.10s, and then the long search to find someone to tune the A/F ratio. I think it would be worth a try. The guy that purchased my GT later found a couple of problems. The fuel filter was installed backwards, presumably from the factory, and one of the headers had loosened up, causing the O2 sensor on that side to read funky and ultimately fail. you might want to check all the intake, outlet seals to be sure there are no leaks that have developed.

KJ Hoppus · Jun 13, 2004

Red2000GT said:
190-200 is awesome compression,there's definately no problem there. How is the car running otherwise? Is it rich(burbs or pops lots when you let off the gas at higher rpms)? I would check EVERY vaccuum line and injector plug and spark plug wire. Also make sure your coil packs are functioning properly and check to make sure the engine ground is re-attached to the body.(it's down low on the driver's side front of the engine,by the oil filter) I've found it's usually something minor that causes problems after major engine work. Also get that 160 thermostat out of there,there's no performance gain to be had by using it,the engine adds timing AND fattens itself up when cold,negating each other,you're just lowering your gas mileage.

the car runns great, no problems. excelent drivability. there is no noticable problems. all the vacum lines have been checked, the plugs, wires were checked, injectors checked. i dont think there is a problem with the coils, if there was i think it would be very noticable. the ground is connected. i will try putting the stock thermo back in, but i dont think its going to make a difference.

KJ Hoppus · Jun 13, 2004

bierbelly said:
Weird. I was running about the same after my headswap, but I was running street tires. One thing I did notice was a definite loss in power after having some Flowmasters welded into my stock system. Go figure. Confirmed by dyno numbers. Needless to say, I'm not impressed by Flowmaster products, but some suggested that the catback system probably works better than the muffs alone. Who knows? What are you running the T/A at? You're in CA, so are you limited to 91 octane? Before I decided to sell my '98 GT (also Rio Red, btw...good choice), my next step was going to be 4.10s, and then the long search to find someone to tune the A/F ratio. I think it would be worth a try. The guy that purchased my GT later found a couple of problems. The fuel filter was installed backwards, presumably from the factory, and one of the headers had loosened up, causing the O2 sensor on that side to read funky and ultimately fail. you might want to check all the intake, outlet seals to be sure there are no leaks that have developed.

weird, on my last car i felt a gain in power down low after getting weld in flows. i am running my t/a at 13, it doesnt ping or buck or anything. i run 91 octane, i can get 92 though. i put a new fuel filter in when i did the swap, its not the problem. i also put on Shortie headers when i did the swap, i know there tight. i am going to double check the intake thought, but i dont hear any vacume leaks.

is it possible that both cams are off one tooth and the compression remains even because of it? that is my current theary.

trinity_gt · Jun 13, 2004

I'd get it on a dyno with a proper AFR meter to know if you need a tune. The added engine hardware plus the intake and exhaust components and, I assume, you're still running the stock 98 PCM calibration might mean you're thin up top in open-loop mode.

KJ Hoppus · Jun 13, 2004

trinity_gt said:
I'd get it on a dyno with a proper AFR meter to know if you need a tune. The added engine hardware plus the intake and exhaust components and, I assume, you're still running the stock 98 PCM calibration might mean you're thin up top in open-loop mode.

i guess ill have to do a duno pull.

KJ Hoppus · Jun 14, 2004

KJ Hoppus said:
is it possible that both cams are off one tooth and the compression remains even because of it? that is my current theary.

does anyone think this is possible??? i dont want to take it apart and find no problems.

trinity_gt · Jun 14, 2004

KJ Hoppus said:
does anyone think this is possible??? i dont want to take it apart and find no problems.

Personally, I don't think so. The cam sprockets have 42 teeth on them. If you had that one tooth off, each cam would be nearly +/-8.6 degrees (of cam rotation, 4.3-degrees of crank rotation) out of phase. I don't think your car would be running the times it is and producing the compression it is with cams out that far.

bierbelly · Jun 14, 2004

trinity_gt said:
Personally, I don't think so. The cam sprockets have 42 teeth on them. If you had that one tooth off, each cam would be nearly +/-8.6 degrees (of cam rotation, 4.3-degrees of crank rotation) out of phase. I don't think your car would be running the times it is and producing the compression it is with cams out that far.

I think you'd notice a lot more problems than just poor 1/4 mile times. Your idle would be screwed up, missing on accel, etc.

COramprat · Jun 14, 2004

How long have you been driving the car after the swap? What were your 60's, 1/8ths and 1/4's before the swap? My guess is practice will get you where you should be. I know I had to drive my car totally different with the gear swap. Different shift points and launches. Same would go with your head swap. It's like falling off a BMX bike but then getting back on a 10 speed. You have to learn to drive it differently to get max potential.

Stangt00 · Jun 14, 2004

KJ Hoppus said:
i dont think tune is my problem.

A tune can make all the difference in the world. Did you do ANYTHING to change or monitor the PCM parameters after the headswap?

KJ Hoppus · Jun 15, 2004

it was my cam timing. both cams were off by 10 before TDC so my engine was pretty much runing very retarded..(literaly)..i checked my engine vacuum and found that it was pulling in 23psi of vacuum and thats what ticked me off that the motor was running retarded and sure enough it was. i have everything pulled apart and we are going to put it back together tommorow.

KJ Hoppus · Jun 15, 2004

trinity_gt said:
Personally, I don't think so. The cam sprockets have 42 teeth on them. If you had that one tooth off, each cam would be nearly +/-8.6 degrees (of cam rotation, 4.3-degrees of crank rotation) out of phase. I don't think your car would be running the times it is and producing the compression it is with cams out that far.

strange, but it was pulling the compression. i dont know lol.

KJ Hoppus · Jun 15, 2004

bierbelly said:
I think you'd notice a lot more problems than just poor 1/4 mile times. Your idle would be screwed up, missing on accel, etc.

thats what i thought too or i would have pulled it apart a long time ago, but no drivability problems, but no power down low.

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