Whitestreak98

yea i was pretty sure the vortec wouldnt handle 400 to the wheels... i meant 400 to the crank... bout 330 to 350 to the wheels

hog

I dont see how a Vortec 350 can dyno at 405 rwhp without additional fuel over the 19 pph injectors.

Naturally aspirated hp takes LESS fuel than FI hp does.

The stock L31 intake/injectors runs out of steam at about 330 rwhp(400crank hp) at teh stock 60 psi of rail pressure.

the stock 19pph injectors are good to about 350-360 hp using FI.

Does the Whipple kit raise the fuel pressure while under boost?? Meth injection would also allow for more power to be made.

James B is running a Whipple on a GMPP 383 engine using the same Marine Intake that I am running.

The GMPP LT4 Hotcam, ported Vortec heads, 383 cubes, headers is a proven recipe for 330 rwhp on a Vorterc 350 using the stock intake and injectors. This setup along with the VMaxx intake spacer will power a 2wd ecab shortbox to 13.7's in the 1/4 mile

405 rwhp, no thats an awesome number, thats around 490 crank hp. Thats the highest number I have ever heard someone dynoing using the stock injection setup.

I have read that the stock poppets become unstable at rail pressures exceeding 75psi, the Multec 2 MPFI Conversion from GM is stable to rail pressures of 100 psi.

Congrats on the awesome Vortec 350 power, just imagine what a Marine/ramjet intake conversion would do. There is simply a whole bunch of restrictions in the stock intake mnaifold.

Can you post a dyno sheet?? Just curious as too teh torque number. Its got to be massive.

peace
Hog

350SS

iTrader: (36)

Congratulations, you've defied most of the fundamental laws of physical chemistry.

Wouldn't happen to be running external injectors w/ the whipple kit would you?

julianmwallace

No, I'm not running the external Injectors, I my kit was purchased in 97, before they ran the extra injectors. The old whipple FMU like mine drastically raises the fuel pressure, mine runs at about 80psi according to my gauge in the higher rpms. I've been told the whipple is only supposed to raise it to the low 70s. I really don't like this high fuel pressure, but didn't know it was that unstable until I got on the PPE forum, but its been running like this for years! I do want to change to the marine intake as soon as possible, as soon as I get enough $$$. I'll try to get some graphs on here if I can borrow someone's camera phone or something, thats why I have no pic in my sig. I have changed/ reworked a lot of things since I've been involved with these forums since summer and feels much stronger than it did.

MCDiver

So what you are telling me is that the 383 Stroker that my NASCAR engine guy is building for me will only give me about 330RWHP? Hope the torque will make up for the lack of power from the engine..............$7.57 per HP................I hope ya'll are wrong.

hog

if you are using the stock intake and 19pph injectors that'll be roughly the limit.

You can always install a fuel pressure regulator to boost the rail pressure for more power.

That engine of yours should work very well. It will haul.

peace
Hog

julianmwallace

I was talked to one of the mechanics yesterday at the shop where I got my truck dyno'd. The owner didn't say abything to me, but the mechanic said they got it recalibrated or something like that last week and the dyno was off about +9%. Thats a lot! So that means my truck is only putting out about 365hp . Well I was feeling really good about my set up for a few weeks, oh well. I'm gonna get an alkycontrol kit and run 11psi boost and hit the 400 mark for real just for you guys. Sounds like the those two things should put me over 400, since my IATs get up to around 200* sometimes.

MCDiver

With the pressure boost, will that increase the ppm of the injectors? Also, what would be suggested for a booster? I am new to the Vortec mods, and am having fun with the engine build. It is a good expirence to be working with a great builder that is well known for quality. He was all excited when we talked yesterday and he decided to make it a 383. We will see, it shoudl be going in about thanksgiving.

Mike

Vortec350ss

iTrader: (20)

If your spending all this money on a new engine being built why dont you get a better intake manifold too, like a ram jet or somthin like that??? Then there will be no issues with the injectors or manifold limiting the power.

-Rob Nap

MCDiver

I have looked into new manifolds for the vortec engines on the 97-98 (99 on Tahoes) and have come up with nothing. The Thorley Tri-y's are the only non-short tube headers I can find. This has not been a fun process. Most of what I am doing will be internal mods. The sad thing is that with all of these motores on the street, the aftermarket will not make parts for us.

Mike