HardcoreABN

So something doesn't seem right. I feel like I should be trapping a lot higher than I am. I am approx 500 - 520 whp NA. 6spd, 3.90s. NA I am trapping 126 - 128. on a 100 shot I trap 130 - 132. 60' times are 1.5x - 1.6x.

My ETs are also rather high, but that is because I am not that great of a driver. 3/4 sec shift times and don't get a clean launch very often. I know with more practice those things will improve.

What concerns me is I feel I should be trapping more on motor and definitely more on a 100 shot.

Any suggestions?

sevinn

Do you have any way to log timing and knock retard and perhaps a wideband?

HardcoreABN

Sure do, will have to get some more next time out. The thumb drive I kept them on got corrupted. I do know that I only get knock retard once in a while during launch and by the time I am out of the hole I have full timing again.

The only issue I have been having with getting logs is getting my widebands to be recorded as well - I have a wideband in each bank before the X- pipe.

JIMS SVT

I think your car should be running at least those times Na. Not on spray.

HardcoreABN

Think it could be a driver issue? I I know I am losing a lot of time with my slow *** shifts, think that could be causing me to lose mph as well?

JIMS SVT

Maybe a little. My 99 made 470rwhp when I first built the 346. Thats rods,pistons,heads,cam,intake,injectors. Maybe it made a little more after it got some miles on it I dont know. That was also the stock 64k mile m6 trans and 342 gears . Last year at two different tracks two days apart it went 10.82 @ 130 and the next track a 10.78,10.79 and some 80's at 132. That wasnt really powershifting either because I had devloped a 2nd gear issue. And you have a 402 wirth alot more power. So Id think it should atleast be in that range. over the winter Ive had the trans all gone through with polished gearset and all the good stuff. Also Added a 3 rib micro polished 410,and all the good parts in the duff. Along with a msd intake over the ported fast 92. Still need to port the msd at some point.

HardcoreABN

The only issue I know exists is my cam is specced for 7500 RPM, but the OEM LS3 intake won't support much over 6200. That will be taken care of when I get the new High HP 102 FAST. I expect to see a good bump in power as I will be making more use of the cam.

the best I managed on motor was 11.1 @ 125.3, but have run slower up to 128.8

JIMS SVT

I have the same issue. Cam is good for 7k+ but intake flat lines it around 6400. What are you shifting at?

HardcoreABN

6550ish.

HardcoreABN

I need to do some acceleration testing then overly the g-forces to see what my optimal shift points should be. Haven't found an android app that works for **** yet.

JIMS SVT

Have a pic of your dyno graph? I shift mine at 7kish

HardcoreABN

not a current one...just one from when I had rather restrictive headers and x-pipe. once I get the 200 shot tuned I am going to play with shift points and such

JIMS SVT

I'm still on 1.75" eBay headers. But a 3" x pipe I made.

HardcoreABN

Here are a few vids of my last time at the track


and its slip




and its slip

larrywalk

A good rule of thumb for ET vs mph is to note that ET x mph should be roughly 1320!
In other words, divide 1320 by your mph and you get an ET that you should get IF everything is optimized perfectly. If you can run 132 mph, your ET could have been as low as 10 flat!

It is interesting that this rule doesn't care about power adders, or type of cam or induction - it's just the physics of the problem!

C5 Hardtop

Don't quote me on this, but I think (prove it right/wrong) its your launch. I know first hand its a pain to launch these cars with the f'ed up 1st gear ratio (part of the GAGS design). Spin too much and I think it reduces the trap speed.

The car in the first vid is leaving a huge patch and its not driving straight down the strip, it fishtails lightly. It took a longer path than normal so it traveled more than a 1/4 mile.

Keep it straight and lean more towards a bog than a spin until you have just the right amount of tire slip. There should be a lighter squeal noise because you want a tiny bit of spin/slip but w/out a bog. Do some searches on suggestions on how to slip the clutch just right with your configuration.
I think your granny shifting is good, less hard on your power train and not the cause.

Gxpz06

that is about the AwSOMENESSES thing I have ever heard... I always try to work it out on my head and with some quick math off your formula this rule kind works right out on my thoughts and goals... most often folks run a number and run to add power and forget that they have a second or two from their et with launch time in the seat..

what I pounder is this... vettes always seem trap higher then lets say mustang for one example... I used to think well its aero and the ls engines like it up top... but now I wonder is it SUCH that mustangs drivers in these instance are Launch it to its Potential ET...

another pounder is would your stated rule work when number get low like in 8s and 7s and so on?!

thanks in advance VERY useful information in the web after all

Gxpz06

HardcoreABN I just saw your tickets again and your 1/8 mile is low --- at first I was going to say your pressure is dropping off hence low traps --- but actually you are catching up crazy quick up top---- maybe your progressor too aggressive..

I never used prossevice spray --- Im at full throddle(full shot) at about 25ft/15mph and it seems to work well --- for my level of experience I say...

HardcoreABN

I am leaning towards it is caused by taking 3/4 a second per shift and the throttle closing during the shift. Losing a lot of acceleration time and losing a bunch of VE with the throttle closing.

I have been playing around with no-lift shifting and damn what a difference even just on the street.

Gxpz06

are you able to NO lift with nitrous?