performance problems with new mods

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hotrod markVIII

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last summer I got a best at the track of 14.4 @ 97 mph
the mods were as follows,
3:73 rear gear, full exhaust (still using the stock manifolds) crappy CAI, and a JMod.

the car would average 14.5 ish

over the winter I swapped out to a 97/98 style intake, removed the IMRC valves from the lower intakes, EGR delete and a better CAI
I also ordered an SCT 3 program chip. with a stock setting a 91 octane tune and a tune set up for a 100 shot of nitrous using a ZEX dry kit.

I had the first run at the track last night And I only got a best of 14.9
the car feels like its running right but its way slower than it was last year.
I'm thinking that there is something wrong with the chip because its faster in the "stock setting" then it is in the performance tune setting.
I have also had a couple of guys tell me that it could be the IMRC delete that is causing the problems. that I need to step up the gears to make up for the loss at low end. but before I did the delete I was looking into it and I was told that as long as the chip is burned for the IMRC delete then its a great mod.
has anyone done this and what was your results any input as to what else may be causing the problems
 
hotrod markVIII said:
over the winter I swapped out to a 97/98 style intake, removed the IMRC valves from the lower intakes, EGR delete and a better CAI
Click to expand...

What intake did you swap to??? Cobra?

I've always heard IMRC delete is best left to boosted applications. But since it's done, you'd be best served with 4.10s or 4.30s with a high stall converter at 3500-3800 rpms. Get that motor out of the 4000 and less rpm band and you'll be happier. 3.73s and stock converter ain't gonna cut it.

Who did the SCT tune? Did you change the MAF with the CAI? You very well may need a dynotune to cope with the IMRC delete.
 
I I swaped to the 97/ 98 style intake.
the chip was ordered form supercoupeperformance and he had a place out in washingtom burn it.
I'm calling next week to get the car up on a dyno. I heard before I did the IMRC delete that as long as you get the chip burned to compensate for the excess air at low rpm's then its a good mod. now I'm hearing different.
I'll have to see what they dyno does and then
 
so I graphed out my best and worst times from this year and last year so I could visually see were the biggest difference was.
and I was kinda supprised.
the 60 foots while slower than last year were alot closer than the car was top end.
it really seemed to fall off time wise from the 594 ft. up to the 1/4
I was really excpecting it to be at the start of the track not at the top end due to the IMRC delete and the newer style intake. the 97/97 style intake is suppose to be better at top end then the older style and it felt that way the car was hitting about 6500RPM at the shift point.
it will be interesting to see what the dyno says.
I'm betting not enough fuel.
maby I should have stepped up to 32lb injectors instead of keeping with the 24's
 
The 98 intake and the IMRC delete are hurting you. My 94 feels 500 pounds lighter than my 98. The 98 is a dog every where compared to the 94. Try putting the original manifold and IMRC back.
 
Gen 2 intakes blow if your going to swap do a Cobra swap but you dont even need this without a KILLER bigger compression na set up or boost. Why would you swap to this intake anyway? Def go with bigger gears and converter for sure.

Should have left the intake alone and worked with what you had, the formulas are tried and proven and have been for years. Stock Gen 1 Marks usually run in the 14.60's.
 
well I'm putting the old intake and IMRC's back on.
it turns out that the guys that I was colaborating with about teh swap. had done it and said it worked great and al that. well they all forgot to mention that they were running blowers. so yeah.
a 14.60 stock? Is that on drag radials?
mine took a 3:73 gear and a jmod to do a 14.7 on street tires
 
I think the no imrc's are hurting you more than the intake manifold swap but yea you should swap back to the gen 1 intake manifold or buy my cobra intake manifold I have for sale.
 
If your gonna go with a blower stick with the gen 2 intake manifold, much easier to install the blower that way and also in my opinion it's a better intake for a blower than the gen 1.
 
its most likely the imrc delete this causes a good amount of torque loss which is causing you to have a slower time off the line until you get to around 3000 rpm
 
98LSC32V said:
If your gonna go with a blower stick with the gen 2 intake manifold, much easier to install the blower that way and also in my opinion it's a better intake for a blower than the gen 1.
Click to expand...

if I go a blower I'll probably go with a late model cobra one.
but I got layed off again so if things dont turn around quick, I may have to sell it.
 
doesnt karkraft make some adapter plates for our cars that would allow us to put on whatever intake manifold? i read that in fast fords a sometime back when they were comparing intake manifolds for the DOHC 4.6 (c heads)
 
well.
I put the old intake back on and then had anther night at the track. on the stock tune I got a 14.9 but the car definatly felt alot stronger with the old intake back one. then I did a couple of runs on the 91 octane tune and I got a 14.7.
its still a bit colder than it was last year when I was getting my 14.4 and 14.5's
I'm definatly having traction issues. but it was running so well I said screw it and opend the bottle, got myself a new best of 13.7 @ 104mph.
spinning the hole way threw second.
it has a lot more in it because my 60 foots were slower than they were last year. I need to find a pair of drag radials.
 
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