ajrothm

Well I got a new PB, first trip out on the new combo, everything went pretty well other then the weather was terrible and the track was stupid crowded with street cars/trucks.

First before we head out.....a glamour shot...


Get to the track, unload, and the fog starts rolling in... DA is already at +1135' at this point.

First pass(#1 slip), a very soft leave, wot about 2 car lengths out.
Second pass, it blew the tires off on a hard launch attempt..--aborted.

Third pass (#2 slip), Launched about 1900rpms, smooth throttle to the floor....a little soft but decent.

Both of those were in full street trim...93 oct, through the air filter, 15* timing.



This is what our weather was doing...


So I pulled the air filter, put the stack on, added some race fuel and bumped the timing to 17*.... Waited in line for about 2 hours, then they decided to shut the track down...It was just too wet every where....

I was happy nothing broke, I was happy with a 9.35 on only the 2nd pass out....I was happy how the RPM trans did....I am a little concerned about the converter...It seems to be driving it through it down the track... 145-146 mph at 6700 on 28"/3.42s is way high.... Probably around 13-14% converter slip....So its definitely wasting some power through the converter.. I was curious as to if it was going to gain mph with my track/setup tune up or just slip the converter more. I'm gonna make a few more passes, hopefully in better weather before I decide if I need to pull the converter or not. I really was hoping for 150 mph traps with the street tune/air filter so.....I may have to do something... Its definitely not showing any HP like this... The scale was down but my best guess is its around 3675-3700lbs with me in it.... 145@3700lbs is only about 750-800rwhp or so.... So its definitely off somewhere.

Now here is the in-car vid:
https://www.youtube.com/watch?v=SGMb...ature=youtu.be

I have a buddy that shot an outside vid, hopefully I can get it this week..

Definitely has more in it, just gonna have to work some kinks out.. I noticed in the logs my voltage drops to 12.5v through the entire pass so the alternator/flip drive belt is slipping.... This is affecting the meth pressure and my IATs were climbing to 115* at the end... So I have to figure that out.... AFR was still in the 10.5-10.7 range, it could stand to be leaned out a bit but, I'll do that last after everything else is worked out.

With a converter swap, track tune/setup and good weather, I could see some 9.00-9.teens, hopefully at 150 mph..... Maybe I can get it during the track rental in March...

mrstepheneades

Sick looking Vette'. Nice runs. The cooler weather seems to be yielding some nice runs for a lot of people.

RonSSNova

iTrader: (3)

Excellent results Alan! Especially given the weather. I'd bet the "correct" converter will help on both ends of the track. Of course not trivial to swap!
Sounds like you needed to be at MIR with the rest of the boys....
I bet it felt good to get out and play!
That's an 8 second car, your job is to get it there!

Ron

JoeMama's GTO

iTrader: (3)

Nasty ride and fast 60's. Looks to be well sorted.

venom ws7

iTrader: (13)

Badass work Alan congrats for an awesome pass..
8s won't be a problem if you let eat without the air filter and race fuel.

ajrothm

Ron we need to have a converter conversation at some point.....I'm sure you know about them and how they should act on the strip...

This one flashed to 5200 or so, shift recovery was 5800..... just seems too loose at 145 mph.... 6700 on 28s with 3.42 gears... That's about 200-300 rpms too high... meaning its slipping away power...

69-chvl

iTrader: (11)

Very nice Alan. Any before/after comparisons between the auto and manual trans?

ajrothm

Hey Vince,

My best with the manual was 9.96@149 with a 1.56 60'.. That was after about 6-7 passes, then I broke the rear end and transmission....for the 2nd time each.... I decided no more sticks. That was in -200' DA and at around 840rwhp.

Last night I only made two passes, air was around +1000' but with very heavy water vapor/fog.... I have no idea how much power its putting to the wheels now, no doubt the auto ate up a ton of power....and I think its driving through the converter which makes it show less power since the mph is down.

I was expecting 150 mph with the auto..

145 mph at 3600lbs, is only showing 750-800 rwhp or so... So its off on the mph for sure.

All of the online converter slip calculators have it at 11.1-11.5% converter slip..... Not TERRIBLE but... not efficient either... I'm not in a hurry to pull the drivetrain again so....It is what it is for a while. I'm gonna try again this next Friday and put another 50hp or so in it and see if it picks up any mph or just slips the converter more...

RonSSNova

iTrader: (3)

It's a Coan? I'd ask them. The 5200 flash is pretty loose. I believe the better converter guys can keep it close there but tighten up the top end.
I remember you commented on how loose it felt driving around.
You have a dyno sheet, they can work from the torque curve.
I'll be playing the converter game with the Nova next year I'm sure.
Ron

ajrothm

Yeah Ron, Davey said to talk to Craig at Coan and give him the data. Hopefully they can figure it out.. I sure don't look forward to pulling that drivetrain again...

I'm gonna try to run it again as is before I pull it apart... Is just like to drive and enjoy the car for right now.. Maybe shut it down in the summer when it's too hot to run it anyway.

I might need to make a little mo powa too...

We'll see..