Thread: Thoughts on a full race motor setup (Turbo Posts)

Great Work!

I am surprised there was soo much difference between the .82 and .82 divided, i suppose the divided had bigger cams, but still nearly 50hp

that vet set up makes great power for 14psi! I almost think he has opted for too big a compressor if he only wants to run those boost levels. sure he is reving to 9.5k but a smaller comp would do that @14psi However it still seems pretty responsive for such a big turbo but it is hard to follow a light green line. Did you ever do a +5 -4 run? would have been interesting to see the results. Thanks for the info i will take it into consideration when tuning mine

The last sheet was not a straight comparison. The .82 divided was a T3 frame turbo with a 60mm turbine wheel.

the other run was a .86 housing with a 56.5mm turbine wheel. This is a T2 turbo which is made to bolt onto a stock nissan manifold. this setup may have had slightly smaller cams but also had 2psi more boost AND the NVCS cam gear was still attached and working and will make more top end power. The main goal with that sheet is showing Spool VS power and how you can have both if you use the right parts.

the VET setup was built for road racing so a nice smooth powerband was better than a peaky one. Above 5000rpm that engine has almost no lag. The engine made just shy of 600whp I was told else where at 9200rpm after installing a better clutch setup. If the motor was only to be run at 14-15psi all the time, then yes, I would have changed the compressor wheel but turbo compressor flow is not linear, thus it will sometimes take a certain pressure ratio to create the desired flow so it is possible that a smaller wheel can cause more lag and less power. This turbo was spec'd out custom and was almost $2000 but did its job.

I probobly spent 3 hrs on the dyno adjusting the cam gears from one end to the other. from -10/0 to 0/+10. the best spool and midrage was made around +6 IN and -5 EX but it was done at 7000rpm. If you notice I have almost 150 dyno pulls with that VET setup, most of those are tweaking the cam gears and retuning for best power. all I can tell you is that with this setup, -4/0 worked the best for what I was looking for but it took hrs to get to that point.

What I can tell you is this. Dont just put the cam gears in at where you think would be the best, just start at 0,0 and go from there. Its rare that you will need to go more than 7-8 degrees off of 0 if you start with the right cams for your power band. SR20VE cams are small enough that cam gear tuning does not yield much. the sr16ve std cams are about 305 IN and 310 EX deg @ .004" lift so there is more room to shift the power band.

One thing to remember, as you advance the exhaust cam and gain power and spool, you are also loosing time and valve open area while the exhaust valve is open and the piston is traveling up the bore to remove the burned exhaust gasses.

Also, when you retard the intake cam too much, you can actually wind up forcing some of the fresh air charge back up into the intake manifold on the compression stroke if the intake valve closes too late. you can however gain power from Inertia from the air moving through the intake port at a very high rate. BUT you have to have the intake valve closing at the right time to "capture" this fast moving air charge.

-Ted

mrslappy = sr20turbofreak?

sr20turbofreak's name was Charles ....

Yeah i know, is just that the VET results are pretty similar hehe.

Chuck made 600whp on his VET

sr20turbofreak?

I hope someone out there try's a Divided T3 turbo like a GT3071 or GT3076R on a VET. killer spool with a lot of power. I have materials to make 2 T3 divided and a few T4 divided manifolds as well.... i havent built one in over a year.

-Ted

I have the cosworth 90mm head gasket and I have a sleeved block on the way , but I am till standard T3 , I still might try the GT3076R , or I might run the GT3582R , I have to many options now !!! is it really that much better to use the divided housing ?? the housings ?? I have are the GTvband ones on the turbos right know

The divided housings do offer big gains in spool if the setup is built around that. A GT35R with a divided housing will spool similar to my T67/T4 dyno I posted. a GT35R is only slightly smaller than that turbo.

-Ted

What are your power goals?