nathan
Junior Member
Posts: 66
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Post by nathan on Sept 28, 2008 21:05:53 GMT -7
First of all I want to let everyone know I am very happy with my 1/4 mile results today in the caddy, that is not why I am asking this.. But this is my question and I know many of you here knows these LS6 setups so I want to ask a couple questions about my caddy.
I raced a couple bolt on GTO's today.. They weigh only 150 lbs less than me. They are rated same power with their LS2 as mine is stock.. 405 HP.. These cars are putting down 320-340 to the wheels and beating me in the 1/4 mile. I am just curious what you think it is? They are NA, no nitrous or power adders at all. I put down 423 HP / 425 TQ on my caddy and the very best I could muster was a 13.3, however most of my runs were 13.6-13.8 range.
I just can't figure it out? I have them by almost 100 HP and yet they are pulling on me hard. Especially since I Have the Roots blower my TQ hits instantly. Do you think there is something wrong with my car, or is it a tune issue? I threw it back on the dyno and it still put down 418 when it was warm, so I know the power is still there.
We are all on street tires, I have massive wheel hop out of the hole but I know that wont change my 1/4 mile that much.. What do you recommend I do from here? I have full kooks long tube headers, high flow cats, exhaust & supercharged LS6 and I can't break 12s? I thought I would hit 12's creeping out of the hole. Just up for ideas guys. As I said, im not mad or upset, I LOVE my car.. but I thought stock LS6's hit 13's without any mods? So I am just trying to figure out what is going on. Thanks.
Nathan
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Post by highpockets on Sept 28, 2008 21:09:17 GMT -7
Tires !!! Get it to hook,I picked up 1 full second going from DRs to slicks(ET streets) best bang and easier on your rear diff(NO wheel hop) oh,and your timing issue is going to be tune or the LPE launch controller(I have one,easy to adjust ) Let me know if I can help you out !
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Post by tachout on Sept 28, 2008 21:52:34 GMT -7
And getting rid of wheel hop will save you a ton of cash. Ask Snowman and Highpockets if Wheelhop is any fun on parts!
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Post by highpockets on Sept 28, 2008 21:57:06 GMT -7
As long as its NOT my car,wheel hop is BADDD for IRS !
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Post by Crossfire84 on Sept 29, 2008 9:01:45 GMT -7
Don't sweat the tune. Even if it can be improved, you aren't living up to the ETs the dyno says you have in there. Before you start worrying about more power, you have to learn how to apply, get the power you have, to the ground. The street tires aren't doing the job. How about some more numbers so we can better analyze. The MPH is the power indicator, the dyno. The 60' time tells the story on traction and car reaction. The relationship between the ET and the MPH tells how well the car is hooking up and how well the chassis is working for you. What is the rear suspension on the Caddie? The gear ratio? My experience is that a tenth reduction in the 60' time is worth a tenth and a half (.15) in 1/4 mile ET. Some say it is worth 2 tenths. I'm guessing you just need a few refinements and some chassis tuning.
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nathan
Junior Member
Posts: 66
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Post by nathan on Sept 29, 2008 11:30:23 GMT -7
I was at wendover yesterday, so I didn't have a 60' and MPH, but I was trying to watch my dash pretty close when I crossed the line to get an idea of my MPH.. I would say about 105-108 mph. That's the thing that worries me though, I really didn't have major traction issues. I mean yes, I had to be kinda slow out of the hole, but it really wasn't that bad. I was on street tires just like the GTOs were. They had about as much traction issues as me, which really wasn't as bad as I thought.
My car has 3.73 posi rear end gears, 6 speed, LS6 with the magnasun charger pushing about 4 lbs of boost. 425 hp 423 tq. since I have raced for so many years my guess on the 60' would be about 2.0, not the best, but decent for street tires.
I just can't pin point how these street tire GTOs with 100+ less HP than me to the wheels are beating me. they are owning me through mid range ( 3rd gear ) and then I start to creep top top end. We have about 100 lb difference, but then the drivers of the gtos easily have me by 100 lbs so we are essentially the same weight. I have a movie I can upload tonight that shows me racing one of the GTO's in car video. I will post it when I get home.
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Post by highpockets on Sept 29, 2008 11:31:31 GMT -7
Its an IRS rear,they are VERY bad on wheel hop,even worse than the vettes so I am told ! With street tires,he is compounding his traction issues. Like you said,mph should be a fair indicator of potential.
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nathan
Junior Member
Posts: 66
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Post by nathan on Sept 29, 2008 11:38:48 GMT -7
I thought the gto's had the same rear end setup? 3.73 IRS.. I know i shouldn't be comparing to other cars, but those gto's are almost the same car as mine, just 100 lbs less.. same trans, same HP rating stock, same rear end.. and yet these NA cars with 100+ less HP are beating me. That is the only thing I can't figure out.. Beating me with 330 WHP compared to my 425. Yes the wheel hop is bad, can't even do a burn out first.. out of the hole me and the gto's were identical through 1st and 2nd gear. then the gto would pull 3rd and i would start to creep 4th but they would beat me by the time the race was over. I just can't understand how a supercharged car almost identical to the other car can't pull a few car lengths ahead of the other car, especially my torque.. I am 423 ft lbs pretty much off idle with the roots blower.. maybe I need to throw this supercharger in the trash and look into a turbo setup.. I just don't understand.. identical drivetrains, identical weights, 100+ less HP & TQ and I am losing and pulling horrible 1/4 mile times with really no serious traction issues at all amazingly.. Im not trying to be a complainer.. to me something just doesn't seem right with my setup and I can't pin point what it is.
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Post by 500hp406 on Sept 29, 2008 13:52:53 GMT -7
Nathan,
I suspect we are running about the same horsepower, and I have an 85 vet. with street tires you have to do everything right to get into the 12s. I run anywhere between 12.6 to 13.6 depending upon how well I hook and shift and everything else. With street tires it is hard to break into the 12s... You will get there...
Wayne
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Post by Crossfire84 on Sept 29, 2008 18:31:59 GMT -7
Yes the wheel hop is bad, can't even do a burn out first.. out of the hole me and the gto's were identical through 1st and 2nd gear. then the gto would pull 3rd and i would start to creep 4th but they would beat me by the time the race was over. I just can't understand how a supercharged car almost identical to the other car can't pull a few car lengths ahead of the other car, especially my torque.. I am 423 ft lbs pretty much off idle with the roots blower.. maybe I need to throw this supercharger in the trash and look into a turbo setup.. I just don't understand.. identical drivetrains, identical weights, 100+ less HP & TQ and I am losing and pulling horrible 1/4 mile times with really no serious traction issues at all amazingly.. We're getting better, more complete info, now. The GTOs do or don't wheel hop? You stay even until they shift to third? What exactly does, "then the gto would pull 3rd and i would start to creep 4th"? You are in 4th gear when they shift the 3rd? You shift to 4th just after they shift to 3rd? Several things come to mind, but I need more clarification. You should have come to RMR Friday night and Saturday and raced with us. I will be stopping by with my computer one if these first days. Maybe, if you have the time we can go over your car problem better, then.
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nathan
Junior Member
Posts: 66
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Post by nathan on Sept 29, 2008 21:02:21 GMT -7
uploading the race now w/ gto.. maybe that will help.. We can go for a ride anytime, I take my caddy to work so if you drop off the computer I will gladly give you a ride and see what you think.. i will reply in a sec, video still uploading.
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nathan
Junior Member
Posts: 66
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Post by nathan on Sept 29, 2008 21:15:23 GMT -7
s236.photobucket.com/albums/ff286/nesluopetan/CTSV/?action=view¤t=S1050938.flvI really didn't have much traction issue out of the hole, I just can't catch him until I hit 4th I start to creep. You all need to understand.. this is a 360 HP NA CAR I am racing here.. Same trans, same rear end, same gear ratio as mine. Same weight, same tires. Both with headers, high flow cats and exhaust.. Now can you see my frustration? It's not like im guessing my HP here.. I threw it on my dyno 10 times.. I DONT GET IT.. i want to scream..
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Post by highpockets on Sept 29, 2008 21:31:53 GMT -7
That car really scales the same as the caddy ? question#2 what are your/his shift rpms? Q#3 trans GEARING identical ? MN12 have different ratios than MN6s,dont know if that applies to yours versus GTO. Q#4 seems like he is about a car length or so ahead of you and as you point out,I would think about 2 car lengths in your favor if all else is equal. Perhaps Jim will chime in,he has WAY more experience than me !
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nathan
Junior Member
Posts: 66
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Post by nathan on Sept 29, 2008 21:46:47 GMT -7
I shift right about 6400.
CURB WEIGHT GTO - 3725 CURB WEIGHT V - 3847
122 lbs heaver.. However the guy driving that car is easily 250 lbs.. I am 170.. Puts us both REALLY close in weight. He is a tiny bit lighter..
CTS V & GTO TRANS GEAR RATIOS: ( they are both identical )
Tremec T566-speed manual with skip shift and reverse lockout on both cars.
Transmission gear ratio (1st) 2.97 Transmission gear ratio (2nd) 2.07 Transmission gear ratio (3rd) 1.43 Transmission gear ratio (4th) 1.00 Transmission gear ratio (5th) .84 Transmission gear ratio (6th) .57 Transmission gear ratio (reverse) 2.90
Final Rear End Gear Ratio Cadillac V : 3.73 Final Rear End Gear Ratio GTO: 3.46
( which makes it even that much more frustrating.. a NA car with higher gears can pull on me like that, with the same trans! )
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Post by highpockets on Sept 29, 2008 21:54:36 GMT -7
What would be interesting is a driver swap/rerun.From the video,like you said,it looks like the GTO has you pretty much the whole way.And NO,it doesnt make sense !
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