Raced on Friday
#1
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From: Medford, Oregon
Car: 1989 Iroc Z L98
Raced on Friday
Well I raced on Friday, had a friend of mine install 3.70's and a 3 series posi in my 9 bolt.
Setup is as follows:
98k mile L98 shortblock, Lunati hydraulic roller similar to LT4 hot cam, shim gaskets, Vortec heads, Summit Stage 1 intake, 650 double pumper.
Old PB with 2.77 gears was 14.15 @ 99 mph on a 2.12 60'
New PB with 3.70 gears is 13.47 @ 102.8 on a 2.01 60'
My runs for the night were: 13.47, 13.55, 13.65, 13.59, 13.70 (spun)
Definitely excited that it picked up, comparing my average runs from last time to this time it picked up anywhere from .8-1 second and 3-4 mph which to me is pretty crazy for a gear swap. Also, it was pretty close to 90* yesterday and not the best air ever.
So I know one major opportunity for me is my exhaust. Right now I am running a custom y pipe into a 3" cat delete, then using the stock over the axle portion of the exhaust into a full size magnaflow 3" stainless muffler. My car is whisper quiet, I just wonder if I would pick up some mph cutting it off and putting a 3" bullet dumped at the axle. Thoughts?
My 2-3 shift was super late each time, that I think is just the TV cable that needs to be adjusted.
Also, I feel like my car should 60' better. It has MT Et Drag radials, it doesn't spin but it does have a very slight pause before it really picks up. The pause was even worse with 2.70 gears. Any ideas on troubleshooting this? It's like the intial hit is hard, then it slightly pauses then goes if that makes sense.
Setup is as follows:
98k mile L98 shortblock, Lunati hydraulic roller similar to LT4 hot cam, shim gaskets, Vortec heads, Summit Stage 1 intake, 650 double pumper.
Old PB with 2.77 gears was 14.15 @ 99 mph on a 2.12 60'
New PB with 3.70 gears is 13.47 @ 102.8 on a 2.01 60'
My runs for the night were: 13.47, 13.55, 13.65, 13.59, 13.70 (spun)
Definitely excited that it picked up, comparing my average runs from last time to this time it picked up anywhere from .8-1 second and 3-4 mph which to me is pretty crazy for a gear swap. Also, it was pretty close to 90* yesterday and not the best air ever.
So I know one major opportunity for me is my exhaust. Right now I am running a custom y pipe into a 3" cat delete, then using the stock over the axle portion of the exhaust into a full size magnaflow 3" stainless muffler. My car is whisper quiet, I just wonder if I would pick up some mph cutting it off and putting a 3" bullet dumped at the axle. Thoughts?
My 2-3 shift was super late each time, that I think is just the TV cable that needs to be adjusted.
Also, I feel like my car should 60' better. It has MT Et Drag radials, it doesn't spin but it does have a very slight pause before it really picks up. The pause was even worse with 2.70 gears. Any ideas on troubleshooting this? It's like the intial hit is hard, then it slightly pauses then goes if that makes sense.
Last edited by unknown_host; 07-06-2013 at 10:27 PM.
#2
Joined: Jun 2002
Posts: 13,572
Likes: 26
From: Harford County, MD
Car: camaro sportcoupe
Engine: 7.0L
Transmission: G-Force GF5R
Axle/Gears: Moser 9"
Re: Raced on Friday
the pause is possibly an accelerator pump tuning issue, or too low of float height, or something along these lines.
yes, you'll pick up with better exhaust, along with going with more of a performer rpm type intake (maybe like a stage II summit intake?) hood clearance with this type of setup may be a problem though. i know you were looking at getting a cowl possibly though. a really mild cowl like a cervini's would be awesome.
the combo has 12's in it...just gotta unleash it i'm glad it's working so much better now with the better gear.
post up more pics of the car
yes, you'll pick up with better exhaust, along with going with more of a performer rpm type intake (maybe like a stage II summit intake?) hood clearance with this type of setup may be a problem though. i know you were looking at getting a cowl possibly though. a really mild cowl like a cervini's would be awesome.
the combo has 12's in it...just gotta unleash it i'm glad it's working so much better now with the better gear.
post up more pics of the car
Last edited by mw66nova; 07-06-2013 at 10:56 PM.
#3
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From: Medford, Oregon
Car: 1989 Iroc Z L98
Re: Raced on Friday
Thanks for all your help Matt! I would like to try an rpm air gap, definitely going to need a cowl hood for that though.
Float level might be low I can check that, I also want to pull my front sway bar before next time.
Float level might be low I can check that, I also want to pull my front sway bar before next time.
#4
Joined: Jun 2002
Posts: 13,572
Likes: 26
From: Harford County, MD
Car: camaro sportcoupe
Engine: 7.0L
Transmission: G-Force GF5R
Axle/Gears: Moser 9"
Re: Raced on Friday
i just scanned through the build blog of yours. are you still using a vacuum secondary carb? secondary opening rate tuning could also help. a double pumper would be better on a lot of levels.
the sway bar is definitely worth some 60.
the sway bar is definitely worth some 60.
#6
Joined: Jun 2002
Posts: 13,572
Likes: 26
From: Harford County, MD
Car: camaro sportcoupe
Engine: 7.0L
Transmission: G-Force GF5R
Axle/Gears: Moser 9"
#7
Member
Joined: Apr 2003
Posts: 121
Likes: 0
From: Frankenmuth, MI
Car: 91z
Engine: 350 vortec
Transmission: built 700r4
Axle/Gears: 373
Re: Raced on Friday
I ran an rpm air gap with vortecs on a stock hood. If you look at it from the side it looks like it would hit. I just used a drop filter and it cleared no problems. I have a 3"cervini now.
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#8
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From: Medford, Oregon
Car: 1989 Iroc Z L98
Re: Raced on Friday
I am running a 3" air filter with a drop base and I have marks on my air cleaner lid where my hood touches. What size filter and how much drop?
#9
Joined: Jun 2002
Posts: 13,572
Likes: 26
From: Harford County, MD
Car: camaro sportcoupe
Engine: 7.0L
Transmission: G-Force GF5R
Axle/Gears: Moser 9"
Re: Raced on Friday
back in my genI days, i ran a holley street dominator p/n 300-36, which was a little taller than a non air gap performer rpm. i ran a drop base and a 2" filter, but had no choke horn to get in the way. i ran the car at the track with no filter (and still do) so no issues with flow.
#10
Member
Joined: Apr 2003
Posts: 121
Likes: 0
From: Frankenmuth, MI
Car: 91z
Engine: 350 vortec
Transmission: built 700r4
Axle/Gears: 373
Re: Raced on Friday
haha o lordy. That was ten years ago. I was going to say it was a 3" drop with a 3" filter but since that's what your running maybe it was a 2" filter. I was running a 3310 holley if that make a difference. God I wish I had a memory. Sorry I'm not more helpful.
#11
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From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
If you didn't adjust it for WOT, well, then, maybe it is the TV cable adjustment. But, that begs the question, why didn't you?
#12
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From: Medford, Oregon
Car: 1989 Iroc Z L98
Re: Raced on Friday
I'll admit I don't know details of your build, but I doubt it's a TV cable adjustment (assuming you adjusted it for WOT). More likely a worn 3-4 clutch pack.
If you didn't adjust it for WOT, well, then, maybe it is the TV cable adjustment. But, that begs the question, why didn't you?
If you didn't adjust it for WOT, well, then, maybe it is the TV cable adjustment. But, that begs the question, why didn't you?
My 1-2 shift is too firm, my 2-3 shift is too late if that helps. I pushed the adjuster all the way in, pushed the button went WOT and that's how I set it, what should I try differently? I might pick up some ET just getting it to shift a bit earlier into 3rd.
#13
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From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Re: Raced on Friday
Push the button & hold while you pull the cable housing back & hold it back, then release button. Go WOT. The cable housing will click forward to the proper setting.
#17
Joined: Jun 2002
Posts: 13,572
Likes: 26
From: Harford County, MD
Car: camaro sportcoupe
Engine: 7.0L
Transmission: G-Force GF5R
Axle/Gears: Moser 9"
Re: Raced on Friday
yeah, but at least you won't have to make it a non-cruiser with a non-overdrive automatic.
#18
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Joined: Apr 2012
Posts: 604
Likes: 1
From: Norwalk, Ohio
Car: 1989 Firebird Formula
Engine: 385
Transmission: Full Manual TH350
Axle/Gears: Moser 9" 3.70
Re: Raced on Friday
I agree. I almost regret putting a Turbo 350 in mine. It was cheap to do, and it's strong, but cruising at 60 mph, it's turning 3000 rpm. I find I drive it a lot less than last year when it had a 700. If I could do it over, I'd probably beef up the 700 to handle 11 second passes and call it a day. Or throw a glide in it and trailer it. I'll never put a non-overdrive trans in a street/strip car ever again.
#19
Joined: Sep 2003
Posts: 25,779
Likes: 376
From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: Strange 12 bolt 3.42
Re: Raced on Friday
Dont you have a converter in it? Probably not enough stall for launch if its not a fuel or tune issue somewhere. That would explain some hesitation off the hit
#22
Joined: Jun 2002
Posts: 13,572
Likes: 26
From: Harford County, MD
Car: camaro sportcoupe
Engine: 7.0L
Transmission: G-Force GF5R
Axle/Gears: Moser 9"
Re: Raced on Friday
#23
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From: Medford, Oregon
Car: 1989 Iroc Z L98
Re: Raced on Friday
lol word . I do know I am not buying a new converter without buying a new trans at this point, I think you may have been on to something with the float level, I am going to adjust that today. I took my car to the exhaust shop and am getting a 3" bullet dumped before the axle, hopefully that will help the flow out a bit.
#24
Joined: Jun 2002
Posts: 13,572
Likes: 26
From: Harford County, MD
Car: camaro sportcoupe
Engine: 7.0L
Transmission: G-Force GF5R
Axle/Gears: Moser 9"
Re: Raced on Friday
sweet! post video clip of new exhaust when you get it done.
oh, [subliminal message]do a t56 swap, don't waste another dollar on a 4l60 based trans[/subliminal message]
oh, [subliminal message]do a t56 swap, don't waste another dollar on a 4l60 based trans[/subliminal message]
#25
Joined: Sep 2003
Posts: 25,779
Likes: 376
From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: Strange 12 bolt 3.42
Re: Raced on Friday
Even tho the lt4 hotcam like cam will want more stall for better 60 fts, it stilllll should be getting off line alot harder than 2.0. A stock car will go 1.9's on street tires with gears, that setup should flyoff the line with a 1.7-1.8
May be a fuel issue or low on timing off the hit
May be a fuel issue or low on timing off the hit
#26
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From: Medford, Oregon
Car: 1989 Iroc Z L98
Re: Raced on Friday
Even tho the lt4 hotcam like cam will want more stall for better 60 fts, it stilllll should be getting off line alot harder than 2.0. A stock car will go 1.9's on street tires with gears, that setup should flyoff the line with a 1.7-1.8
May be a fuel issue or low on timing off the hit
May be a fuel issue or low on timing off the hit
#27
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iTrader: (14)
Joined: Mar 2000
Posts: 43,169
Likes: 36
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
I've been running a 9.5" Rev Max 4L60E converter built for about 3600 stall. He'll make one for you in TH700 style. Good piece at a very decent price.
About the muffler: I'm running a 3" mandrel bent I-pipe into a single in/out 3" Magnaflow muffler. The car ran 11.95 @ 114 MPH last September at Heartland Park Topeka.
If you have a dual outlet crossflow muffler, I agree, it'll be restrictive. Having run Bullets on the '57, be aware it is NOT a street muffler - loud, crackly, droning, extremely annoying. If you want a good straight-through 3" muffler that flows like a Bullet but is quiet enough on the street to not make a bad name for 3rd gens everywhere, check out an Aero Turbine 3030, and mount it in the stock location. Use a single 3" exhaust pipe out to the bumper.
If you have a stock I-pipe, yes, it will be a restriction as well.
#28
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From: Medford, Oregon
Car: 1989 Iroc Z L98
Re: Raced on Friday
I hadn't messed with my float levels since getting my fuel pressure regulator dialed in, both primary and secondary float levels were low. I raised them last night, adjusted my TV cable again, fixed a shifter issue, and get a 3" bullet muffler installed yesterday afternoon. Going to race it again tonight we'll see how it does.
#29
Joined: Jun 2002
Posts: 13,572
Likes: 26
From: Harford County, MD
Car: camaro sportcoupe
Engine: 7.0L
Transmission: G-Force GF5R
Axle/Gears: Moser 9"
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