96 tahoe w/CPI 5.7 want power
 

I have a 96 tahoe sport I want to build the most powerful engine I can drive every day. I was thinking of the 6.0 swap but if I can stroke my 350 it might be easier/cheaper for the same power? I'm going to be installing a sts turbo with the new engine I need to know how far to go with the cam and head work . :devil:

well, the big prob w/the 96-98 + a few 99 5.7 vortecs is that you cant really upgrade the fuel system so that limits you in the power department. I would check out ls1truck, some of those guys have put the lsx based engines in there trucks, i have thought about it myself but im not too mechanically inclined so probably not.

You could do a ramjet swap.
This is a 98 Silverado, its bagged and lays frame on 20's. Weighs in just shy of 5000lbs. It has a bone stock long block all the way from the pan to the rockers.
GM Perf. Ram Jet intake, LS-1 TB, Custom fuel rails, 57lb/hr squiters, Aeromotive fuel sytem, Made 375rwhp@4600rpm and 485rwtq@3600. With a P1-SC @12psi. It went 12.84@107 with 14PSI and good fuel.

http://pic2.picturetrail.com/VOL962/.../107769630.jpg

http://pic2.picturetrail.com/VOL962/.../107769639.jpg

http://pic2.picturetrail.com/VOL962/.../107769610.jpg

http://www.dragtruck.com/ENTRIES/DHD3P4H0A45J.html

Ram jet sounds like the way to go
 

The only reason I was going to do the 6.0 swap was the fuel issue I have with the cpi. I know the 6.0 can handle the sts turbo and make a ton of power my friends caddy ext. ran 13.62 on the 6.0 and 8psi

hey whats the deal with the ram jet? how much are they? and what else is done to the L31?

There is a magnacharger supercharger kit for them I believe.

Nothing is done to the motor it is bone stock all the way up to the valvecovers. The Ram Jet intake is straight from the GM Performance parts mag. The rails are custom made in house for clearence for the stock type distributer. The injectors are 57pd/hr delphi units. The stock PCM runs it all. The stock harness is just modified for the injectors. Works great.

were did you buy the ram jet? and how much was it? Do you know how I can get the GM performance parts mag. were you found it or a web site.

I am using 1 of these, using this marine intake allows use of all the 1996-99 accesories as the TB is in the stock position.
http://www.sfatek.com/images/efi.jpg
There is 1 of these for sale for $750US with injectors and all the wiring and \weatherpack connectors. The supercharhed guys are saying that the high rpm power is way up over the stock intake. I agree, but I am naturally aspirated. I can rev it right up to the 5800 rpm rev limit.

here is the link of our little marine intake conversion project.

http://www.pacificp.com/forum/viewtopic.php?t=317


You can get that Ramjet intake manifold at any GM dealership that has a Parts Counter. Go ther and get the GMPP Catalogue. Brand new Ramjets are expensive, try and find a used 1. The parts are over $2000CAN for a complete Ramjet setup.

Both of these iontake are MUCH better than the OEM L31 intake as ALL the injection equipement is outside of the intake manifold instead of being INSIDE where the air is impeded.

The stock intakes have POPPET injectors that are rated at 19 lb/hr and have a limit of roughly 400 NA crank hp, even lower if force induction. You will need either of the above intakes, or take a Vortec Carb intake and fshion it with injectors and fuel rails. (Isuggest either the Ramjet or Marine intake)

I suggest that you build a 396 smallblock, get a 1 piece seal 3.75" stroke crank and machine the rod journals to the small 283 size, overbore a 350 block to 4.060 and you have a 395, 396 has a better ring though. It easily could be a 396 after the rings break in. These engine kits are only about $200US more than building a 383 engine. Maybe a forged 383 with the larger rod journals might be better for overal strength, with your turbo plans, high rpm wont be needed. Dont plan on spinning ANY engine over 5800 rpm using the Vortec PCM. As of today there is NO fix to raise the rev limiter over 5800 rpm. Many North American tuners can raise the limiter from 5600 rpm(stock) to 5800 rpm. I have spoken to many people and have some people working on this problem right now. I had Ed Wright try and set my rev limiter at 6100 rpm, and when I received the tune, I checked his work and sure enough he inputted that I receive a 6100 rpm rev li9mit, but alas only 5800 rpm is attainable. With my marine intake, there is no sense in installing a cam that has over a 5800 rpm capability as I cant rev that high. When I hear anything about the 96-99 Vortec rev limiter problem being solved, I will post for all to see. Util then no 5800 plus rpm.

You could also build a 406, a 434 or a 454 smallblock Chev. if you want to use the Vortec style heads, I would grab a set of Aluminum fastburn heads, these were used on teh limited production(430 engines made) ZZ430. They have 210 CC intake ports a 62cc combustion chanber, LT4 sodium filled exhaust valves, LT4 lightweight valvtrain and even come with LT4 springs. these heads flow enough to support over 500hp flow better on the intake than the Vortec iron heads, and considerably more than the Vortec's poor exhaust flow numbers.

Another route would to be dump the Vortec system altogether and get a Stealram or similar intake. Any sized fuel injector can be driven by the L31 Vortec PCM so long as they are high impedance. If you get awy from the Vortec heads, the cylinder head choices open up.

The STS turbo you will be installing will make any of these combos really work good. lare displacement cylinders really spool up turbos quickly as stroker engines have large exhaust pulses.

since Tunercat OBD2 has comeout, you can now easily change make changes to the PCM to allow for the larger injectors you install.
The stock truck intake is said to pop when boost is over 12 psi. The Ramjet or Marine intake will handle much more as they are both completely metal.

Hellbents did the Ramjet swap and I did the Marine intake swap, just his year, dont dump the GEN 1-E Vortec system yet, its just getting interesting for the L31 scene, anyone can install a GEN 3/4 engine. i have talked with manyNorth american PCM tuners and no-one has tuned for a Marine Intake manifold, many have tuned for tuned ports on Vortecs, but no marine intakes. Hellbents posted the very 1st Ramjet conversion I and alot of people had ever seen. That truck he built for a customer is wild,and only getting wilder.

For your turbo engine, keep the compresion ratio fairly low, use high quality forged internals, and consider getting different coatings applied to your engines internals. these coating aid in the way heat and energy is tranferred thru an engine. They help build hp and keep an engine together. Your tahoe is heavy, I suggest a 4l80e conversion as well, or at least a big dollar 4l60e build. I would go 80e though, then your dont have to worry as much about the trans all the time. Also you will need a 14 bolt 9.5" ring gear rear end out of the 454SS and 3/4 ton trucks to hold the turbos huge torque an hp.

good luck and keep us posted, post back with any questions


peace

Hog

I figured you would show up on this thread, thanks for posting the great info. The Marine intake swap is definatly more bolt on freindly. A little bit easier and it looks stock, great for running steath. I agree with you on the L31 we are just starting to have fun with it and its a very capable motor.

We just took the heads off the Ram Jet truck yesterday. Everything looks great. Its ready for another season of abuse. Now its getting E-tec 200's and a cam. Along with a bigger "air pump" lol. We are going to see what the short block is worth. I bet it will make 500 to the tires and not even flinch. We will be spinning it to about 6k or so. We also bolted up a 4l80e and got the crossmember relocated for it. Now we will pull that out and go through it. We don't want the trans holding us back on our hp testing now do we.

Get a blower on yours Hog!!! It will be fun I promise lol.