New Guy!

[454SS/SC]

I hope you guys will bear with me; I’m new to supercharging and this board.



I have a 1990 454SS pickup. About 2 years ago I found a Vortech supercharger kit for it. As is common, plans and free time change. I was working on another project and it kind of sat for a while. The other project, a 1974 Vette, hit a snag but I already had the engine built. So I dropped that engine, a 496 in the SS for a while, it was making 578hp and 588tq at the flywheel.



While the 454 was out of the SS it was rebuilt with forged pistons, Edelbrock TBI cam, intake and headers. A set of slightly worked GM 781 oval port heads top off a 4 bolt block with pretty good rods and ARP bolts with a cast GM crank. I think I can live with the cast crank due to the low rpm, under 5,000.



It’s a lot stronger than I thought it would be! Stock the 454SS only had 230hp and 385tq with max torque at 1,600 rpm. Friends with similar mods are getting around 320-350hp and 430-460tq at the rear wheels. I was not sure how much the Vortech would add. I think it’s faster in the 1/8th than the 496 was! Granted the 496 needed a 3,000+ converter and I was running a 1,400.



It ran really well no the trip home, about 400 miles at 65-80 mph and has not set any codes. It’s only making about 5 psi boost and I’m letting it shift it’s self at around 4,500 rpm, I think it’s pretty well done by then anyway.



I am having two problems! Belt slip and fuel leaking around the TBI shaft.



I have ordered a new crank pulley, 8.5” vs. the stock 7.5”. On the SC I’m planning to us a 3.12” vs. the stock 2.87”. I hope this will reduce belt slippage as well as provide a little more boost. Stock compressor speed at 5,000 rpm is 45,022 the new pulleys will up that to 46,920. Is this a problem?



For the problem of fuel being forced out the TBI shaft (I think it’s only happening during deceleration) I plan to add a second bypass valve close to the SC outlet. We tried a Mondo race type bypass but it was slow to close, I think it was just to big!

Thoughts?



Al 454SS/SC

[pavement pounde]

Hi there fellow 454SS man,

Aldough I have a Paxton, I also have the Vortech dual injector plate for under the tbi for more fuel.
You do have that plate to ?
As noted in the install instruktions witch you can download at http://www.vortechsuperchargers.com/welcome/ in pdf format
There must be drilled two very small holes in the bottom of your tbi to prevent blowby and thus leaking some fuel along the trottle shaft (just drops)
Becouse I have enlarged the bore of my tbi I did not have any room for the small holes, so I have made some o-rings on the inside of the trottle shaft, that should work also.
Btw are you familiar with the http://www.454ss.com ?