23* or 28*

[suburban]

what would you guys run with a 44, 23* and 25 lbs boost or 28* and 21lbs boost.... going to the track sat nite.

 

[99Formula]

I'm far from an expert, but I think you'd be hard pressed to find 5 degrees of timing making more power than an extra 4 psi of boost.

Peter

 

[TurboDave]

If you have access to good enough fuel. You can have your cake and eat it too. Use 28º and sneak up on 25# of boost.

My race profile is 28º of timing and 25#+ of boost.

BTW, at the track I run Unocal 114 exclusively.

 

[suburban]

thanks for the replys guys. turbo Dave, I have both a pte 28* and a 23*. the 23 is working awsome on the street with alky, the 28 has a little too much transitional but I was thinking of giving it a whirl with c16. I am running 24-25 lbs on the street @ 23*. this is a unopened motor and I want to be carefull with timing...... thanks, John.

 

[blackbuick87]

Should be able to run the 28* with C16 no prob. Be careful with 110. Start out about 22psi and work your way up

 

[Tom87GN]

On this issue of chip timing, I'm wondering if I get my 26* race chip lowered to 24* or so if I will gain some mph at the big end.

My car went 12.06 at 109 (running 22 psi with 730 low 02's) but I couldn't get her into the 110-111 mph range to save my azz! My uncle who has been racing small block chebbies for many years says that taking a few degrees of timing out of the chip will give me more at the big end, providing that my car makes enough power down low. I think with a 1.67 short time, it's doin allright! Anybody think it's worth a try?

I run Unocal 114 leaded fuel at the track.

 

[blackbuick87]

The only time less timing makes more top end is if you have too much to begin with. You will slow down with less timing. There is something bottling you up somewhere else, either intake (heads/IC) exhaust.

If you are getting KR less timing may make you go faster

 

[Tom87GN]

Actually, I wasn't getting any KR during my last 8 runs at the track. I am totally stock when it comes to exhaust manifolds and heads, so I know that is restricting me, but others have gone faster without upgrades to heads or headers. The IC is a CAS V4 and I have a dump tube, so those aren't factors, I wouldn't think anyway.

I was just wondering if there was any truth to taking some timing out of the chip. Thanks for the reply blackbuick87!

 

[suburban]

Tom, if your not getting any kr why not try another pound or two of boost and see if anything changes........ John

 

[tim87tr]

Originally posted by suburban
Tom, if your not getting any kr why not try another pound or two of boost and see if anything changes........ John

Yea Tom, that's what I always tell you. That's easy for me to say when it's not my car . I think adding a couple lb fp static and one or two psi boost, then decreasing the fp on the next pass if the O2s are too high with no kr would be the way to go.

Good thing is the car is dialed in now for that 11, just needs that extra tweak. When I get my 49, you can tell me the same thing too I didn't know your O2s were running that low. I stopped decreasing my fp at 770s

 

[Tom87GN]

My 02's run pretty low at the big end, something like 700's-740's by the time I hit 110 mph. I'm a bit leary about adding another lb or 2 of boost because I feel I'm pushing the dreaded head gasket envelope. I'd do it just to get my 11 second pass if that's all I could do with my combo. But, if I can get it somewhere else in there, I'd rather try that first.

I think maybe I need some more track time to mess with the fp and the boost.

 

[blackbuick87]

You should have plenty of injector for 110mph. Sounds like you need more FP

 

[jayster]

Nice! You said you hit 109 with stock exhaust setup..
Hooker Cat Back with Hooker Aerochamber mufflers system was worth an IMMEDIATE 4mph in the traps with NO other mods. Just bolt on, and i gained .1 in the 1/4 and 4mph consistently. THere's your MPH you want, and it's only $350 from Kirban. Bolt that on, and you'll go 11's every time..

BTW - you got a HOT short-time'd GN. My car goes mid 12's at 108MPH...if you're goin 12.09@109...you have a MAJOR bottleneck holding back your true power potential. I'd bet my bippy that if you freed-up your airflow, you'd run 11.80's easily with that kind of short-time. What's your 1/8th mile time?

Cheap test - unbolt the exhaust at the cat and see what happens. You have a 3-inch downpipe already? If not - you're gonna FLY with a 3" downpipe and open exhaust or a Hooker or ATR 3" exhaust. Wow...

 

[Tom87GN]

Jayster, I have a 3" Terry Huston downpipe with a track cutout already. I know something is holding me back from 111-112 mph. After I installed the RJC power plate, the car dropped .2 in the 60' time! I love it!

My 1/8th mile was a 7.61 @ 89 mph.

 

[jayster]

Cool that you already have the goods there, so it's something else holding you back. Your 7.61 1/8th mile time translates into 11.80's chief..actually 11.86 to be exact, so you're losing your oomph in 3rd gear for some reason. Does your chip scale-back boost in 3rd gear, or reduce timing at upper rpm's? You're losing .2 at the top end, so at least your 1/8th mile time shows that it's not the low end or 1st or 2nd gear.
The others are right i think - you're too lean at the high-end showing you need your fuel curve adjusted in your chip - or raise your fuel pressure. If you're not retarding or knocking - you can add a good amount of boost back in and still not have to worry about it.