92TPI383

iTrader: (1)

Car specs, 91 Firebird, T-56, 3.23's (I know...).

Engine is a 4 bolt billet splayed main 383, ~10.5:1 (EDIT 10.1:1), forgot what iron heads but 2.02/1.60, cs-1013r cam (214/224 adv duration .443/.465 lift 112lsa), comp roller tip rockers, stock TPI intake, shortys/Y/3" back, 24# FMS injectors, '730 8d with a modified AXXD bin.

Issue is I get huge amounts of spark retard at tip-in and I have read tons of info on here and have been playing with it for about a month now and just can't seem to figure it out, car cruses nicely. When going WOT, there is a half second bog and then it takes off. I am using Tunercat and Datamaster to log. I still dont have an AFR gauge, and know I need one bad, but I'm away at school and trying to figure something out. I am gonig to try and link my recent log today and my tune. If anyone has some input it would be hugely appreciated. Thanks!!

I'm using a file sharing thing, I'm not sure how to do it otherwise, again help on that would be awsome

Tune: http://www.mediafire.com/?q4okbdut0cdujuo
Log: http://www.mediafire.com/?j80epzc2qdhuu63

bjankuski

10.5 to 1 compression and iron heads with a small cam is probably too much compression for pump gas. You may be experiencing detonation and there may be nothing you can do to fix it other then changing hard parts. With that being said you need to verify if you are actually getting detonation. Can you hear any pinging? If not it may be false knock that is generated when the aftermarket pistons generate a frequency that is different then stock and sets off the knock sensor. If you do not hear any knock you can try and limit the spark retard at WOT this will restore your lost power but make sure it is not knocking before you do this.

Orr89RocZ

iTrader: (20)

yeah you may need some good gas or meth injection to help this setup. that is a good bit of compression and small cam.

Verify your VE tables are in line and no lean spots are there which could cause hesitation. Sometimes you hit spots like that and its not tip in. Also verify you are getting PE mode enrichment in. Sometimes factory setting are 70% TPS when you can be half throttle and require a much richer fuel curve than your VE table is targeting (BLM's going for 14.6-14.7). I've seen this happen before.

Whats your timing in the areas this occurs? You being high compression/small cam, its not gonna want alot of timing.

92TPI383

iTrader: (1)

I can't hear any pinging, but it may be suttle, the car is pretty loud. I run 93 100% of the time, and don't seem to be seeing any specs on the plugs. Would a larger cam and/or intake help aleviate the "detonation"? I am planning on throwing a HSR and a Lunati 60103LK on in the next two months. I'll have to check out my build sheet to make sure I am correct on the CR.

Edit: timing is only around 20-22 when I get into it, I have a very flat timing curve, I'm guessing due to the restrictive intake and small cam? I'm almost wondering if I might have an injector problem, maybe having a lean cylinder giving me the knock. I also heard from the bushes that my roller tipped rockers can set off the knock sensor.

Orr89RocZ

iTrader: (20)

Larger Cam will keep dynamic compression lower so during cruise areas at lower rpms and mid range throttle roll on's you will have less cylinder pressure and less likely to detonate. Not saying its detonating now but its a good possibility given that compression on iron heads.

92TPI383

iTrader: (1)

Took a look at my build sheet today, actual CR is 10.1:1, so that is somewhat a relief. Where would one start on the AE tuning? I have read the page "little some thing i put together on $8d AE tuning" more times than I can count, but can't quite understand it that well.

Orr89RocZ

iTrader: (20)

Thats definately the thread to look into if you feel you are lean on tip-in situations.

Those 2 are probably the ones i'd try first.