ive been driving my car on the streets a bit and everything has been great, ive done some 3rd gear pulls on the interstate, 11.2:1 afr conservative timing at 8psi. so i decided to take the car out to the track friday night to see what it would do, i was only getting a 1.9 60 foot as i was feathering it off the line, it would pull great through first and second but in third it would start braking up/surging like a **** at which point the wideband was useless so i would let off the gas, lets just say my best time was a 11.6 at 106mph with a 1.9 60 foot. i had a mixture of 93 octane and 5 gallons of vp110 ust for peace of mind.

My guess is either 1)my needle and seat are too small, i am not sure what is in it, when i called kevin at csu he didnt remember
2) i am running NGK tr6's at .032 gap doubtful but could i be blowing the spark? i have the new msd 6al-2 dig. prog.

this has to be a timing or fuel issue and since first and secong gear were fine as well as on the interstate 3rd gear pulls were fine i am guessing i am running the bowls empty?? i have two walbro pumps in tank but i have only been using one lately.

my carb does not have vent tube extensions and when i called kevin he ust said run it as it is and see how it does, is it time for some extensions?

On a happy note, transmission ran great, i love my new ptc converter, engine ran nice and cool at 180* all the time so no more overheating problems for me, the transmission ran nice and cool as well at ~145*

 

i am pulling all plugs today as well as removing the turbo system because i havent retorqued the heads yet and its time to.

 

... I would re-gap them to .028 either way.

How much timing are you running...?

Cometics...?

 

yeah im gonna try regapping them

36 full timing with vacume advance to 40*, and locked at 36 until about 4 psi to compensate for 8.5:1 compression then from 4 psi to 8 psi it drops to 23* degrees

yes i do have 3 layre cometic gaskets with arp studs, i changed my mind and dont feel like taking it all apart right now so im gonna put that off until some other time lol

i took my carb apart and got some spects,
both needle and seats are .140
rear jets 73 with extenstions
rear boost referenced power valve (BRPV)
front jets are 66
front PV unknown number 6.5? mabye idk
#31 squirters

i just checked my rotor and cap and it seems like there is alot of rust on the rotor and cap so im gonna clean that up or get new ones.

 

Odd that it pulls well in first and second but breaks up in 3rd. Thats about where most load is but there are high g forces in acceleration during 1st and 2nd. That makes me question fuel delivery issues but it still could occur. I wonder if fuel pressure is dropping off at all?

 

Yeah I'm gonna start from scratch and check everything again timing fuel vacumehosed I went and picked up a new set of tr6s and gonna gap them at .028 check rotor and cap and reset the msd box hopefully one of these things will fix it

 

I agree with Orr, the fact that it starts happening in 3rd sounds like a fuel delivery issue. What is the wideband saying when it happens?? Your carb setup is very different from mine, but I don't have a CSU carb, just a regular mighty demon 650 I have tuned myself. Without vent extensions I had to run size 99 jets in the rear and 70's in the front with .069 PVCR's. This put my WOT around 11.4-11.9. After adding vent extensions on both, I was able to go down to 91 jets in the rear and 66's in the front and it runs 11.1-11.4 at WOT. Also my carb has .110 needles and seats and no issues with them being a bottleneck yet. When I first put my plugs in for the turbo I gapped them at .025 and works great. Maybe I could go bigger but I figured why mess with it since the gains would be insignificant.
If you get back into it after letting off does it run ok? Hopefully you're not detonating when that happens.