H/C/I guys get in here

twotonefreak

New Member
Feb 23, 2003
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Fortsmith,AR
:( Alright guys I finally got my new engine done and up and running for a couple days now. The new combo is a TrickFlow Street Heat upper and lower, stock GT-40Ps, Trick Flow Stage 1 Cam (221/225,499/510) Hedman LTs, and at the moment stock T-body and MAF :notnice: Untuned until I have those :( and Aeromotive Adj. regulator. I have had trouble finding the right amount of timing and fuel press. to make this thing more happy than it currently is. Just curious what fuel press. you guys have run that worked well, and for you guys with GT-40 heads what degree of timing worked well for ya? Also what heat range plugs would you guys suggest? Thanks beforehand for any input. :nice:
 
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What's the LSA on that cam? Is it giving you fits? Or do you have a chip/EEC tuner?

I run 10* base timing and then use the TwEECer to advance it throughout the curve. For fuel pressure I'm at 39 psi. Plugs are Autolite 3924's (one heat range colder than stock, you'd use Autolite 24's on the iron heads).

Dave
 
Sorry I left that out. 112. They are the iron heads also. I don't have a chip or any tuning aid right now. The idle isn't giving me fits, just when under a light load and WOT. Is acts like it is getting too much fuel but doesn't have the smoke or smell to it. I am trying to figure out a base line on the basics so I can tweak it from there and get everything lined out until the new T-Body, MAF and tune. Right now I have Motorcraft 32s in it(not platnium) and timing about 12 is where it has seemed to do the best at so far. The EEC has done a great job of learning how to idle with this cam, especially after hearing some peoples horror stories. I had it set up fairly well yesterday but had to pull the dist. and intakes to fix a coolant leak :bang: and now it just doesn't seem very eager over 3500 like it did yesterday. I spent 2 hrs or so tonite trying diff. stuff but I gave up until tomm. when I can put the scanner and gauges on it and drive it. Also did you set your TP voltage at.9-1 with your combo?
 
My FP is at 40lbs, but my WOT setting are 7% richer from 3500-up with my eec tuner. My intial timing is at 10, and my global spark advance is at 4... this would be like running 14* of timing. I bet 12-14 is the MAX you'd want to run. As for fuel, I'd start at 38 with the line off and work from there. If you don't have a dyno, you could always do this at the track. Your SOTP meter can often lie to you so going by "feel" can be misleading.
 
Thanx for the input guys. I will spend some more time on it again tonite. Gonna hook up the Snap On scanner and fuel guages and see how everything is doing. I just want to get it running a little better before I take it to have a chip done. :nice:
 
I run autolight 764s,gapped at .040.(I have nitrous,you could probably run .045-.050)
16degrees of timing.(You shoulnt go over 13 untill you get some injectors.)
With 19lb injectors you are gonna have to turn that fuel pressure on up.Id start at 45lbs with the line on.
 
twotonefreak said:
mine are .45, I thought that was the stock gap?
No, it is really and truly 0.054. For a boosted application you obviously need to close the gap a little, to prevent spark blowout. For maximum horsepower, you want the biggest gap you can get that still sparks reliably.

Dave
 
I agree with everything Dave said. My plugs are gapped at .052" A lot of people I've talked to have told me that I'm running them too open and that most H/C/I cars are set up with plug gap around .045" but I look at it like everyone else, the more spark I can expose the more efficient burn I should accomplish (at least in theory). If I was boosted, I'd run them at .035" unless you could get away with more with an aftermarket ignition. BUT be careful as MANY blown guys have pulled their hair out looking for problems when it was simply spark blow out. My dad went through a similar situation in his NA 91GT. The car would just stop pulling at 6500 and sound liek it was hitting a rev limiter. We tried eveything on the dyno with the chip, and we replaced the coil, etc. The we took the plug gap from .052 to .040 and BAM the car pulled to 7000rpms. He then added an ingnition to be on the safe side, but plug gap made a world of difference even in him NA application.
 
I just know i had my plugs gapped at like .045 when i first put my thumpers on, and i had a stumbling problem around 3500-4500rpm. Re-gapped them to .054 and the stumble completely vanished.
 
Idiot you will def. notice the lope to it, most everyone else will also realize that it isn't stock anymore. Only gripe I have with it is that it will bog a little under 2000rpms, but what I love about it is when you hit about 3250, you feel it start to take off and then around 4200 it takes off even harder. If you have a H-pipe, you notice the cam even more.