For those interested in serious performance upgrades for the8.1engine,realize that nothing from the old big block 454-502 engines except exhaust manifolds will fit this engine. It is a completely new design. Our company has been working with this engine for nearly two years now, and we have developed a new high performance aluminum head that will start shipping in March. We are finishing final design and tooling for a new intake manifold which should be available in April-May. Our new camshafts with special profiles will be ready in April. If you going to spend money right now, invest in a good set of 4 into one headers coupled with a good cat back muffler system, best use of your dollars right now! Don't waste your money on $400 plug in programers,$300 throttle bodies,$200 MAS's and $200 high flow air intakes,they won't give you 10 HP total at the rear wheels. The stock (90lb each) iron heads,the steriod looping intake manifold and an anemic camshaft are the power chokes. Our flowbench and dyno work has proved this fact! Our new heads, intake and cams will take this engine to true 450hp-550ft/lb emissions compliant level! This should start some #!^~ conversations!! I'll answer all questions with truth and fact! Something a little rare in the aftermarket industry right now!!

 

any sneak peak pics?

Sounds interesting.

 

I'm with this guy, I want to see some pics.

 

Sorry Guys! Can't post pictures until our new Web site is up and running. That will be Feb 1. @www.raylarengine.com. The pictures and complete specs will be there and a special intro offer on the new "BIGPOWER" heads. Mark your calenders and stay tuned for some great parts!
Thanks for the replies.
Raylar

 

VERY COOL. 8.1 is sweet!

 

As you probably know I run two modified 8.1 trucks. One is a Suburban that made 407 rwhp with an intercooled Whipple, mid length headers and other bolt-ons and the other is a naturally aspirated Silverado HD with a Comp Cam, mid-length heads and most of the other parts that you said don't work

A high flow induction by itself will give you at least 10-12 rear wheel horsepower, handheld programmers are good for about 15-20 depending on the vehicle, a ported TB is about 8-10 and the same from some of the MAFs on the market. Alot of people go with these parts in the beginning and end up with more than 10hp total.

It sounds like you might have some good coming up though

Tom



2002 8.1 Silverado HD - Comp Cam, TOGs headers, Volant induction, Direct Hits ignition, 8" lift 18" wheels/tires + more
2002 8.1 Suburban -Intercooled Whipple supercharger, TOGs headers, Volant induction, 22" wheels/tires + more - 407hp/558 ft-lb torque at the rear wheels.

www.tbyrnemotorsports.com

 

Finally more another company with performance mods fer the 8.1. Take ur 450hp slap on a intercooled whipple and 7-8lb boost pully. Since 7-8 lbs of boost should add about 50% (+-5%) more hp thats 450+225= 675 of good ole torque filled big block horsepower. Throw in forged internals and a 75/100 shot and...

 

I forgot to ask if that was flywheel or rear wheel horsepower.

 

Sorry,Engine Horsepower, I don't think the stock 4L80E tranny would take the 575-600hp very long to get 450hp at the rear wheels. I am still at little bit confused how all these expensive quick upgrades can work so well. If you take the 20hp programmer, 10hp air intake system, 12 hp throttle body and the 10hp MAF change you now have taken the engine from 340hp to 392 hp which should translate to a net rear wheel horsepower increase of about 42hp. I have yet to see a truck go on a dyno stock, make these changes and put out an addtional 42hp on a calibrated dyno with corrections made for altitude pressure and air temp. We have been making out of the vehicle engine dyno pulls on this engine for over a year and a half and after CNC on the intake manifold entrance and exit ports, a BBK 80mm throttle body, no intake air cleaner, 85mm MAF and using our computer program to maximise the fuel and spark curves we could not get the stock motor to pull more than 375hp at 5400rpm with shorty headers and no mufflers. The reason we feel is the stock cam, with its a very small duration and lift profiles for low rpm torque and emissions holds the key. Maybe I am missing something, show me!

 

I added a shift kit to my 4L80 to insure that it continues to provide me with firm shifts but the rest of it is stock. Hopefully it stays that way I figure I'm looking at about 520hp/715 ft-lb at the flywheel with the current mods.

The numbers I posted for the other mods were at the rear wheels. Those are most of the common upgrades that people usually do. The low average is about 40 rwhp which is what most people see.

The stock heads and cam are very conservative so there are definately some good gains to be found. My Silverado uses one of Comp's mild 8.1 cams -

46-408-9 Comp Cam -Great torque, good for towing & RV’s. Works with O.E. exhaust and intake - 206/212 .510/.510 112

High RPM horsepower is as important to me with this truck. I run tall tires and use it for towing so a strong low to mid range is what I need to see.