I'm just really disappointed with the results of my heads and cam swap. Perhaps I was expecting too much. As a bolt-on car it had run a best of 12.85 @ 105.x mph. I installed ported stock heads and an XE230/236 cam w/ 1.6 rockers. I did everything right for a change parts wise and bought good stuff the first time. The heads have good flow numbers. Since this, my best time is a 12.45 @ 109.8 mph but i typically run 12.5x @ low 109 mph. The car is an A4 w/ Vig 2800 stall and 3.73's. Granted, the car is heavy since its a convertible, but still... Even once I swap from MACs to long tubes, fix some other minor issues and get retuned I still can't see it running better than 12.3's @ 110-111 mph. Does this sound right for a 3750 lb vert (with me in it)? Maybe I'm just spoiled by my very lightly modded (and very light) LS1 car that will run 12.6x @ 112 mph on street tires without so much as headers on it.

What are you other heads/cam LT1 guys running and whos heads and what cam do you have?

 

Has it been tuned yet? If not.. I'm quite sure that's where most your problem is... If not all! LT's will help.. And a bigger converter would be nice as well..

 

Yeah, it was dyno tuned once but it turned out it really wasn't ready for the dyno. I'm adding a vacuum modulator kit to the trans so it will hold line pressure at high rpm and also so I can put a bigger stall in it without the OBD1 no shifting burnt clutch pack condition. I'm also gonna re-lash the valves and install long tubes. I may possibly switch from a MSD Digital 6 to a Delteq too. From there I'll get it retuned. I only see it picking up maybe 15 rwhp from that, though. Not sure how much a ported intake would help.

 

I've seen quite a bitmore power come out in tuning... You'd be surprised.. i don't see any h/c LT1 runniing those numbers... You should be 12.0's easy.. possibly 11's w/ a bigger verter..

 

Um...Times and mods in sig. With ported stock casting heads, and a CC305, I'm running 12.0 @ 112 MPH...With a stock suspension and a full weight car.

Don't get discouraged, though. I went 12.82 with a stock engine, and then did heads/cam...The first time out, I only went a 12.74. After replacing the clogged fuel filter and installing a new PCM, I dropped to a 12.38 immediately. Further tuning brought it down to 12.0.

Frank

 

I remember that day!..

 

im running mid 11's with home ported heads a gm 847 and a mail order tune.

 

94_Z28_ragtop,,,

I was running 12.70's @ 109 before headers and when I added the LT's I went down to 12.49 @ around 111mph. The car was running very lean from the addition of the LT's. Since then I've added a cut-out, had TR add in some more fuel which it needed and then I added an electric water pump which in fact made it just a little on the rich side because of how much cooler the motor was/is running. I haven't been able to go back to the track beacuse of a new job, going back to school, etc. So, when I do go back, hopefully I will run some better times, especially when I start to do some suspension work and add some 1.6 or 1.7 rockers.
You should pick up with some LT's, more tuning on the Dyno and possible an electric water pump. BUT, make sure to start tuning your car after adding both of the above and not before as I did. I'm even thinking about waiting to retune until after I add the rockers and lose a little more weight on the Z which you should also consider doing.

12SCNDZ--> I think I will be changing out my fuel filter very soon as it's been quite a while since the last change! Kinda thinking about new O2's as well since the ones I have are original.

Later,,,,

 

Hello,

New to this site, nice one it is for sure. I noticed you had mentioned 12.8's with just bolt on's, sweet. Would love to get that recipe as I too have a '94 Z/28 convert. Purple pearl with black top. Thanks in advance, Darrell

 

Welcome to the board!

 

Welcome to the board.. I sent ya a PM as well...

 

Thanks guys, that looks like a good recipe for this convert. to start with. What is the, Bypass throttle body, statement meaning? And how do I read(get to) my PM(private message)? I just can't seem to find it. Thanks, again.

 

With heads cam you notice a huge gain with some gears, 4.10 gears ussually add about 4 MPH in the 1/4 mile from what I"ve seen, that being the only difference from last setup guys run.

Matt.

 

I noticed you mentioned vacuum modulator for your trans, isent the 94 electronicly controled?
as for your times you might want to compair to other cars at your track also. Here in hawaii at one of our tracks all cars seem to go alot slower than one would think, maybe its the driver but every one seems to run slower here. 1998-2000 camaros seem to run 14s at 100-101 mph and 93-97s seem to run mid to high 14s, the last convertable A4 I seen ran 14.6 at 96 MPH and it had at least a exhaust

 

my car ran mid 13's on street tires, i did a head/cam swap and was expecting mid-low 12's on et streets??? maybe i'm shooting to low also?