thunderstruck507

iTrader: (18)

I usually run 1/8th, but finally got to a 1/4 track. I was on 325/50r15 ET streets. This is with the chevelle from my sig.

DA 1842

60 ft: 1.7776
330ft: 5.0621
1/8th: 7.8091
trap: 89.55
1000: 10.2091
trap: 101.81
1/4: 12.2473
trap:110.38

I feel like this trap speed is showing low for my mods. My raceweight should be right around 3700# with me in it.

I was expecting around a 115mph trap.

There was a 98 camaro with: lid, ls6 intake, 1 7/8 headers, open exhaust, 9in 3.90 gears who was also trapping 110.

608kZ28

one thing i learned over the years is its all about how you get off the line and the 60 foot. ive seen all kids of cars and trucks trap 110 mph and get a low to mid 13 second pass. then i have also seen cars trap 110 mph and get what you did.
looking at your 60, the slip seems about right id say. what the camaro run?

ive noticed people are placing too much emphasis on trap speed when they should be paying more attention on the times

dkbmxer002

iTrader: (5)

not sure about with your mods but the slip seems right across each line.

thunderstruck507

iTrader: (18)

He was street tires so he was light out of the hole, best was a 13.0@110

608kZ28

my point exactly. he didnt leave the line as hard as you. maybe he even spun the tires a little.

thunderstruck507

iTrader: (18)

True, but I was just looking for confirmation or hints my dyno numbers might have been a little low. As is, they seem right on par at ~355-360rwhp@3700#.

For my mods, I would just think that is 15-20rwhp on the low side. Just curious.

I do have some 799 heads to port and get put on, but I will also need injectors. Supposedly my stock 98 injectors are at 94% DC which also seems odd to me at 350rwhp. People claim they are good to well over 400rwhp.

stumprrp

iTrader: (2)

those tires are 30" arent they? that could be an issue with only a 3.42 gear.

thunderstruck507

iTrader: (18)

28"

my previous best 1/8th mile was 7.85 with 275/50 (just under 26") Nittos

Quick Sh0t xMLx

A 26" tall tire would probably work better with that gearing. What PSI did you have the tires down to? How were you launching? 1/8th trap vs 1/4th trap is a bit off, how is the 2-3 shift on that trans?

thunderstruck507

iTrader: (18)

The tires are borrowed honestly...it was them or use my hard as a rock 400treadwear street tires. Guy said I can buy them if I like them or return them if I don't.

I had them at 18psi that pass. Gave it 1/2-3/4 throttle off the line, felt it stick so I hammered down then and it stayed glued.

2-3 shift is great (trans is fairly new and well built to what most shops call stage 2) but I think tire size threw something off, it kissed the limiter on the 2-3 for a moment. Never happened on the street when I was playing with them.

Maybe the cutouts being open gave it just enough to spin it up quicker?

The calculator I used actually predicted I would hit 12.22 in the same DA and the DA was a little better (1840 versus 2800 on my previous best of 7.85). But I don't put a ton of faith into those.

Quick Sh0t xMLx

How was the track prep? I think with the tires aired down to 15 PSI and just straight hammering it off the line your 60' could have been better. I could see the difference in tire height throwing off the shift, that little bit might have been 1-2 mph who knows. With some 26" DRs I can see it in the 11s at the same DA.

thunderstruck507

iTrader: (18)

First day the track was open so it needs to get seasoned. Damn diesels were ripping up the rubber and a c6 dumped his clutch from about 5k and blew the rear on the line...stayed in it and put gear oil down the whole track. He was going sideways every gear.

I had them at 18psi the first pass and dropped them to 15 later but the track was getting worse, not better.

bjamick

iTrader: (31)

To be honest, I would pull that reverse split cam out and go with something more traditional. Your setup is just not working together. Get like a 230/230 EL torro or something along those lines and watch the power rise. I would think it's right on par for the power your making. Your 1/8 is a pretty decent mph but the 1/4 is kind of weak.

thunderstruck507

iTrader: (18)

I'm already debating a cam swap when I put on the ls6 heads. Thinking something in the area of 234/238.

Technically the "el torro" is still a reverse split. It has equal advertised duration, but more intake lift.

I also feel my 1/8th mph is great but the 1/4 is down a couple so I agree there.

bjamick

iTrader: (31)

Well the term reverse split is usually referring to the durations. Sometimes they do work, but in your case I will have to say it's not working at 100%.

Ya a nice 23x cam should make it wake up, especially if your adding ls6 heads. Probably put you around 420 or so rwhp.

thunderstruck507

iTrader: (18)

That's what I would hope for, but that's a long way from the current ~355rwhp the car is making.

That is the cause for my concern with the trap on the big end. It pretty much backs up my low dyno numbers.

nmass399

looks like you might have not hit the speed traps and then started slowing down. I know the ones at my track are a little bit after the finish line. Your 1/8 mile mph looks like you should be trapping around 112 to 113 at the 1/4.

608kZ28

like i said i think your slip is pretty much on par. i checked 6 different online charts and calculators and going by your 1/8 mile time, you are only off anywhere from .02 to .05 seconds.

thunderstruck507

iTrader: (18)

That's what I'm finding too now.

But that still means based on my 1/4 trap and dyno the car is making ~355-360 rwhp. I was hoping for at least 380rwhp when I picked the combo (and that's assuming I just got a ls6 intake).

For a non baby cammed ls1 with ported fast intake, 25% underdrive, no a/c, 1 3/4 longtubes, dual cutouts in 3" pipe, 850cfm K&N cone filter, and dyno tune to 13:1 a/f ratio I was just hoping for a little better.

Granted the 12 bolt, heavy drag radials, stalled auto, and 3.5" chromoly driveshaft (56" long no less) is causing some serious loss.



Going to go over everything with a fine tooth comb looking for mild vacuum leaks (why the hell would 28.5# injectors be maxed with 350hp?), make sure all the rockers are tight (had one loose before), and might try to borrow a larger air filter.

Next time at the track I will also try unhooking the front bar to see if it helps launch.

Camaropar

iTrader: (1)

1/8th to 1/4 discrepancy? Sounds like you have some converter slip going on, possible trans slippage.