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

I'm with freeman

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.

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.

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.

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:)

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.

New as in upgraded new or new as in new stock? Upgraded differential and your coilover's set at a soft setting should help a lot on launch.

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 +?

And different gearing...

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

Well, you're 60' times are great!! My best was 2.05 as stated earlier. I can't remember my times for 1/8 off the top of my head but I know for sure my best mph was 99.**mph. I'm guessing you're right around mid 11's too, with your 60' times that is

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. :)

the difference is that your running a nitto 555r drag radials and he is running just a nitto 555.

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.

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

He wasn't talking about you.

Jim, there has been some confussion about what car I was driving. My LT1 is not up yet:mad: I was driving my brother's single turbo FD.

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.

Well, that explains a lot. :rlaugh:

Sorry to hear that.

I bet you were quite confussed at my 420rwhp at 20psi:D I plan to have it up very soon though. Probably going to run 8psi. I really don't think it's gonna last long though. I'm already saving some money for the stroker kit;)

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!)