Looking for info on a TVS/15+psi set-up:

[cozmo2806]

Hey guys, Im looking into going FI. I have been fairly heavily involved in the 03/04 Cobra world for quite some time now. I have recently built a coyote swap fox mustang for a change in scenery. It has a studded boss motor with lightly ported livernois heads with comp stg 1 blower sticks in it. (got a deal on this motor, didn't assemble it this way)
Part of me would like to just throw a TVS on it as it is and see how I like it, but I have a feeling I'm gonna want more. My other way of thinking is to yank the motor, bump the compression down to 9.5:1 and pulley it to 15-17 psi. I would like to see some results and info of what that 2nd option will do. I always loved the big tq of a properly setup TS 03/04 Cobra. Lets hear some opinion.

 

[Scott8583]

I'll be running 16lbs of boost on 11.25:1 Diamond pistons with my TVS. On corn for fuel. I wouldn't go the 9.5 route. What pistons does it have? My old set up was 10.5 to 11psi on stock pistons. Made 600+ Could have been more like 650 if it was on E85. Stock Boss pistons & rods are stronger then GT hardware I believe. VMP runs over 800whp on their stock long block Boss on race gas I believe also...

 

[cozmo2806]

I'll be running 16lbs of boost on 11.25:1 Diamond pistons with my TVS. On corn for fuel. I wouldn't go the 9.5 route. What pistons does it have? My old set up was 10.5 to 11psi on stock pistons. Made 600+ Could have been more like 650 if it was on E85. Stock Boss pistons & rods are stronger then GT hardware I believe. VMP runs over 800whp on their stock long block Boss on race gas I believe also...

It has the full Boss 302 rotating assembly. If I had E85 readily available I'd go that route. This will have to be on 93 octane. I drive my car too much for anything else. Any particular reason you would stay away from the 9.5:1 setup?

 

[Scott8583]

Torque loss...

I'd run an 82mm on a pump gas tune & then switch to a 75mm & race gas on a race gas tune at the track. It takes about 3 minutes to change pullies.

 

[cozmo2806]

Torque loss...

I'd run an 82mm on a pump gas tune & then switch to a 75mm & race gas on a race gas tune at the track. It takes about 3 minutes to change pullies.

IMO, the tq loss come from the blower not being spun hard enough. No different than the 03 Cobra. Guys put on a Whipple or KB and run 13-14 psi and wonder why they only make 520 tq. These blowers need to be spun. This will be a pump gas (93) setup. Like I said I drive my stuff alot and want to have it all there. I can put the really small pulley on if I go to the track. I'm really afraid of being stuck with the 82mm pulley on pump gas and it being soft down low with the 11:1 compression/10 psi setup. Am I wrong?

 

[Scott8583]

The Roush/VMP TVS is a whole new animal. It doesn't need to be spun hard, power is instant. I launch at 1500 rpm & pull 1.54 on street tires with a 79mm. I had stock fuel system. I'm sure you could run a 79mm on pump gas with a good fuel sys. I went 10.60's @ 3900 lbs w/ stock motor, stock auto, & stock converter.
In a fox body around 3300 lbs your looking at low 10's high 9's on pump gas. Throw in a smaller pulley, more timing, & race gas and your looking at solid 9's

 

[cozmo2806]

Ok sweet. I just have seen a few graphs where they looked a little soft down low compared to a terminator graph. I just assumed it was because of lower boost.

 

[prn1972]

I have a full bolt on coyote with Roush TVS. 75mm pulley making 15 psi on 93 pump. About 700whp.
Stay with 11:1 like everyone has said. The TVS makes better low end torque than a TS.
If you want more & don't have e85 available. Run meth injection. That's what I'm doing on my new build.
And I would go with the Gen 2 vmp TVS kit. Newer design & better upgrade options.

 

[cozmo2806]

Yeah, I guess I could look into that. Not a huge fan of meth, but its probably from lack of experience with it.