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-   -   8.1 Engine Mods (http://www.classracer.com/classforum/showthread.php?t=69058)

Tom Meyer 02-19-2018 04:45 PM

8.1 Engine Mods
 
At one time someone had post on chevy 8.1 engine mods, intake pcv relocate and tune info? Love my 8.1 suburban , exhaust is getting bad and needs upgraded. Tom 402-329-6795

Biscayne 02-19-2018 06:59 PM

Re: 8.1 Engine Mods
 
Id contact Black Bear Performance in Ca. For a custom tune. Don't waste your time or money with a hand held programmer. As far as exhaust, i know they make shorty and long tube headers. I have an 8.1 suburban, had Black Bear custom tune and just a replacement 3 inch muffler installed. You will be very happy with the custom tune.

Ed Wright 02-19-2018 08:04 PM

Re: 8.1 Engine Mods
 
Tom, I typically get close 40 hp & 50 ft lbs at the tires with that engine. Biggest gains of any engine I have worked with. GM had to de-tune the heck out of that one to get them past EPA & CARB. Picked up my 8.1L Motorhome 5 MPG while towing. If you are coming to a Tulsa race, I can do it there. My wife is having health problems now, that will likely prevent my racing this next season, or I could do it at one of your races.

Mike Casteel 02-20-2018 04:31 PM

Re: 8.1 Engine Mods
 
Do you have to run premium fuel after the pcm mods?

RULER 03-08-2018 07:04 AM

Re: 8.1 Engine Mods
 
So are these big gains in mileage and power done with stock exhaust and regular fuel??? If not what modifications will need to be done?? For those improvements

Alan Roehrich 03-08-2018 07:38 AM

Re: 8.1 Engine Mods
 
You can gain a pretty fair amount with just tuning, Ed is correct, the factory tune is abysmal. There are tunes that use the different grades of fuel. It's still a big block Chevy, it likes timing, and timing likes octane.

There are people gaining substantial additional power and fuel economy with headers and a free flowing exhaust.

There are a couple of people modifying the intake by removing a substantial restriction, some are adding a bigger throttle body, and killing the EGR, as well as relocating the PCV system, because the PCV system will literally suck oil out of the lifter valley.

The intake and exhaust work has shown another 30-50 HP, depending upon how much intake work is done, and depending upon your use and driving style, another 2-3 MPG. If you constantly use the added power, you won't help fuel economy at all.

I have been developing a bolt on adjustable rocker system, but it is on hold right now. The plan is to have both stock ratio rockers for those upgrading the camshaft but not replacing the pistons, and 1.8:1 rockers for those keeping the stock camshaft.

stock1080 03-08-2018 09:20 AM

Re: 8.1 Engine Mods
 
Please keep me in the loop. Have a 1999 3/4 pickup I want to use to just tow my trailer to races. I never thought there would be any help for that thing. jeff

Ed Wright 03-08-2018 10:10 AM

Re: 8.1 Engine Mods
 
My GM Calibration Engineer ("tuners" on the internet) friend told me about what all they had to go through to get that engine past EPA. No timing, and a 60 second P.E. Mode delay. Like the power valve on your Holley carb not opening until you had the gas pedal on the floor for a minute. They had to keep them out of P.E. (Power Enrichment mode) during the drive cycles in the EPA testing. Shortening that delay, or setting it to zero, is a mileage killer for people with poor driving habits. I have ridden with people that move their right foot all the time. Their mileage will be lower than other's everytime.

Adger Smith 03-08-2018 10:51 AM

Re: 8.1 Engine Mods
 
Ed, Do you have to do the tune on the truck or can I just send you the ECM?
Mine is a 2002 1 ton.
Hope your wife is doing better..

Bob Don 03-08-2018 01:46 PM

Re: 8.1 Engine Mods
 
I'll be following this thread. I have a 2002 2500hd 8.1/Allison for towing.


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