8.1 Engine Mods

Tom Meyer · 02-19-2018, 05:45 PM

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, 07:59 PM

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, 09:04 PM

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, 05:31 PM

Do you have to run premium fuel after the pcm mods?

RULER · 03-08-2018, 08:04 AM

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, 08:38 AM

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.

02-19-2018, 05:45 PM	#1
Tom Meyer Senior Member Join Date: Aug 2003 Location: Pierce NE Posts: 900 Likes: 51 Liked 301 Times in 105 Posts	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 __________________ Tom Meyer 5240 SS Stock ???

02-19-2018, 07:59 PM	#2
Biscayne Junior Member Join Date: Jul 2005 Location: Md Posts: 93 Likes: 0 Liked 2 Times in 2 Posts	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. __________________ Scott Chalk 1226 I/SA

02-19-2018, 09:04 PM	#3
Ed Wright Veteran Member Join Date: Mar 2005 Location: Sand Springs, OK Posts: 8,132 Likes: 896 Liked 389 Times in 168 Posts	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. __________________ Ed Wright 4156 SS/JA

02-20-2018, 05:31 PM	#4
Mike Casteel Junior Member Join Date: Feb 2011 Posts: 15 Likes: 0 Liked 1 Time in 1 Post	Re: 8.1 Engine Mods Do you have to run premium fuel after the pcm mods?

03-08-2018, 08:04 AM	#5
RULER Member Join Date: Jan 2006 Posts: 219 Likes: 15 Liked 57 Times in 17 Posts	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

03-08-2018, 08:38 AM	#6
Alan Roehrich VIP Member Join Date: May 2006 Location: Murfreesboro TN Posts: 4,907 Likes: 993 Liked 1,030 Times in 269 Posts	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. __________________ Alan Roehrich 212A G/S

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