Disappointing results at the track w/ TO4S
Well, after finally getting everything tuned right, fuel pressure holds, boost holds, everything on this FD is awesome. It dynoed 420rwhp but that was with the boost dropping to 16psi after 6K. Messing around with the boost controller lines it finally kept 20psi all the way to redline. So I figure it has about 460-480rwhp.
Ok, now to the track.. Running low boost (14psi) the best time we got was 12.6 and best trap speed was 117mph. I know the time sucks but there’s just no way out of the uncontrolled wheel spin in first and second gear. It would stick after launch but as soon as 5500rpm came, it just shot to redline. This was also ran on street tires (275/35/18 Nitto 555). Best 60’ was 2.2 Now high boost:) First gear was ran at 14psi then with a hit of a button on the Profec B, I had 20psi. It took me about 5 runs to finally find out how to launch this sucker. Meanwhile I managed to get the highest trap of 124.17mph!! Still struggling on the launch the best time I got was 12.1 at 121mph. The 60’ on this was 2.05. This is still with massive wheel spin at 5K but at least this time I kept on it instead of shifting and resulting in bogging 2nd. 2nd still spun but at least there was no bogging. This was also the last run of the day at 77degrees. The FD was heat soaking so we just called it a day. Pretty disappointing cause I thought we’d be deep in 11’s. It certainly has the traps speeds for it, just need the tires now |
get some et streets and it will be a different story
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I'm with freeman
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Found your solution (kidding) just install this rear end and wheel setup: http://www.luvtruck.com/Gallery/Proj...s/IM001300.jpg
In all seriousness get some ET streets, drop that pressure down and pray your clutch, u-bolts/drive shaft, diff, and rear axles all hold up :) |
Yeah, I know the tires have alot to do with ET, especially when we're talking 11's. This was just the first time this FD has hit the track.
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I don't know of many FDs that have gotten into the 11s on steet tires. Usually 12.0 to 12.1 is a great time with street tires. With ET streets you can drop you 60 down to 1.7-1.8 and get low 11s. Probably 125+ traps too - don't be hard on yourself...that's a serious car for the street.
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What tire pressure and what rear suspension are you using? I've found that running softer springs in the back will yield better 60 ft times.
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Yeah, I know running 11's is pretty damn hard w/ street tires but with trap speeds of almost 125 I just thought it would be easy even with a bad launch. The car has Tein HA coilovers, sock rates set at its lowest. Tire pressures were never checked or changed. We wanted to see what it would do strait from the street. I think the next mod for this FD is gonna be a new differential:)
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Awesome trap speeds!
Even with high trap speeds it is very hard to make up for time lost off the launch and in 1st and 2nd gear spinning there just is no chance of making up the time. A few years back some guy ran mid 10s with a 150+mph trap speed in a C4 Vette twin turbo'd, he also had traction problems. |
Originally posted by LT1-7 Yeah, I know running 11's is pretty damn hard w/ street tires but with trap speeds of almost 125 I just thought it would be easy even with a bad launch. The car has Tein HA coilovers, sock rates set at its lowest. Tire pressures were never checked or changed. We wanted to see what it would do strait from the street. I think the next mod for this FD is gonna be a new differential:) |
are you sure you have that much hp? I ran 5 runs and got a best of 12.125@121 with ~400rwhp on street tires dynoed 380 but I had the boost up .5psi and it was very cold out and also used the water/alcohol inj.
Im not wasting my time again going to the track. just roadracing. i dont want to tear up my car with the launching. my car had hop and spin until 60mph on those runs. its not worth ruining a great car |
Isn't the best trap on stock twins 125mph +?
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Originally posted by LT1-7 I think the next mod for this FD is gonna be a new differential:) Still, at least your car is running. :) |
my t78 put down 439 on 16psi. last night at the track (1/8th) i managed to squeeze out a 7.32 @ 96.59 with a 1.66 60ft. i'm not sure what it would work out to in the 1/4, but i'm guessing 11.3-11.5 at around 120ish. i was using 245/50/16 nitto 555r's as well
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Originally posted by spoolin93r1 my t78 put down 439 on 16psi. last night at the track (1/8th) i managed to squeeze out a 7.32 @ 96.59 with a 1.66 60ft. i'm not sure what it would work out to in the 1/4, but i'm guessing 11.3-11.5 at around 120ish. i was using 245/50/16 nitto 555r's as well |
I've got a T04S also making right around the same power as your car... Got a copy of your dyno for me by chance?
I agree about the 5500 RPM... as soon as you get up over 5k, the wheelspin is crazy. Right now I'm running 225/50 R16 R compound road race tires (not for dragging, on the street) and I have no prayer of getting traction in 1st, 2nd is quite scary to control... 3rd is OK unless it's winter time and the tires are cold, road is cold, and air is cold - all leading to less traction and more power. If you want to get the best drag times, you need some FAT back tires that are dedicated for dragging. Like some other people said, then you need to pray that your diff doesn't break. |
John, you would never be able to run that much boost on a mostly-stock LT1 if you weren't pushing most of it out the exhaust. Your cam is hurting you badly, I suspect, and you're running far more boost than I would have expected. The Halltech twin turbo kit for the 10.5:1 LS6 only runs 9 psi and makes ~625 horsepower. 12 psi requires race gas. With 10.4:1 static compression ratio, your dynamic CR must be extremely low because of the cam. From the nasty lope your engine had in the video you posted, I'd almost bet that your cam is even bigger than the specs you posted.
Your real liabilities at this point are the 4.10:1 gearing in your differential and your cam, in my opinion. Fix those, and your car should be a real terror... not that a street car that traps 12x isn't. :) |
Originally posted by spoolin93r1 my t78 put down 439 on 16psi. last night at the track (1/8th) i managed to squeeze out a 7.32 @ 96.59 with a 1.66 60ft. i'm not sure what it would work out to in the 1/4, but i'm guessing 11.3-11.5 at around 120ish. i was using 245/50/16 nitto 555r's as well You are making way too much power for that tire to be able to pull anything better then a 12.0 off. Thats not too bad of a time anyways. If you put ET streets on there you should be able to get into the low 11s high 10s fairly easily. |
Originally posted by fastcarfreak You are making way too much power for that tire to be able to pull anything better then a 12.0 off. Thats not too bad of a time anyways. If you put ET streets on there you should be able to get into the low 11s high 10s fairly easily. |
Originally posted by spoolin93r1 how do you figure? the tires hook great. i guarantee if i would have been at a 1/4 track on that run, it'd been mid 11's for sure |
Originally posted by jimlab John, you would never be able to run that much boost on a mostly-stock LT1 if you weren't pushing most of it out the exhaust. Your cam is hurting you badly, I suspect, and you're running far more boost than I would have expected. The Halltech twin turbo kit for the 10.5:1 LS6 only runs 9 psi and makes ~625 horsepower. 12 psi requires race gas. With 10.4:1 static compression ratio, your dynamic CR must be extremely low because of the cam. From the nasty lope your engine had in the video you posted, I'd almost bet that your cam is even bigger than the specs you posted. Your real liabilities at this point are the 4.10:1 gearing in your differential and your cam, in my opinion. Fix those, and your <A TITLE="Click for more information about car" STYLE="text-decoration: none; border-bottom: medium solid green;" HREF="http://search.targetwords.com/u.search?x=5977|1||||cars|AA1VDw">car</A> should be a real terror... not that a street car that traps 12x isn't. :) My FD will be running next week sometime. I just found that my alternator is not charging. So I'm on a 3 day wait from Summit Racing. |
Originally posted by LT1-7 Jim, there has been some confussion about what car I was driving. I was driving my brother's single turbo FD. My LT1 is not up yet:mad: |
Originally posted by jimlab Well, that explains a lot. :rlaugh: |
Congrats...
Those #'s are not bad at all......
Practice....practice.....that's what you need:D You need drag radials or ET streets when you start making power. FYI: I ran 11.08 and 11.11 @ 124-125 mph on 245/50-16 Nittos drag radials with awesome 60fts (1.6xft) launching between 3.5-4krpm and rear shocks set on hard. Good Luck |
Those #s are great !
Congrats yes get tires and drop your tire pressure and practice (dont break! sometimes wheelspin can be your friend, cause when you hook .. ouch!) |
Hey John. Hopefully this weekend, I'm going to take my single out and see what it'll do on low boost. (14lbs) I hope to break 120mph...if the clutch will hold in 4th. :D CJ
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Hey CJ! my first run on 14psi, I got 117 so you should get into 120. I'm planning to drag my car on july 2 in the street legal drags. good luck! later, James
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I imagine strip racing is pretty thrilling. But why this obsession with drag racing a car that was designed to carve canyons and road race. The real fun in driving these cars is taking sweepers and on/exit ramps at 80+ mph and it feels like 30mph, All the while watching your passenger tighly grip the door handle wide eyed. Or cruising at 60 on the expressway when a smug 911,M3,Vette driver attemts to show you up and you downshift to 3rd and giggle as they dissapear behind. You laugh even harder when you brake to let them catch up and they won't even look over at you, or better yet they give you the thumbs up. Leave the drag racing to Mustangs,LS1's and Grand Nationals.
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imagine strip racing is pretty thrilling. But why this obsession with drag racing a car that was designed to carve canyons and road race. The real fun in driving these cars is taking sweepers and on/exit ramps at 80+ mph and it feels like 30mph, All the while watching your passenger tighly grip the door handle wide eyed. Or cruising at 60 on the expressway when a smug 911,M3,Vette driver attemts to show you up and you downshift to 3rd and giggle as they dissapear behind. You laugh even harder when you brake to let them catch up and they won't even look over at you, or better yet they give you the thumbs up. Leave the drag racing to Mustangs,LS1's and Grand Nationals. I only got one run before the clutch let go. :( I boged the launch pretty badly, then spun the tires through 3rd gear, then hit 4th and there was'nt any clutch to help me. So, I coasted from there and still ran a 13.6@110mph. I need to buy a pressure plate, and slap everything together, and I'll head back to the track. CJ |
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