grimjaw
1/2 ton status
I am looking for a Cummins 3.9BT specific forum. ANyone know of a good one? I am getting comparison info together for different diesel options. Thanks.
CK5
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Looking for a Cummins 3.9BT specific forum, Help!
- Thread starter grimjaw
- Start date
grimjaw said:
Whar are you doing the research for?
I haven't found a 3.9 specific forum but I know of a couple of guys that have it in their K5 and they say it works great.
grimjaw
1/2 ton status
I am comparing the cost, reliability, possible power, fuel economy and ease of swap between the GM 6.2 -6.5 and Cummins 3.9BTs.
BowtieBlazer
Diesel Powered
look for the 4bt group on yahoo, there are a few of us on there
grimjaw
1/2 ton status
I have that group. I am just looking to see if there is any more places to get info.
Thanks.
It would help if there was a program like Desktop Dyno for Diesels.
Thanks.
It would help if there was a program like Desktop Dyno for Diesels.
CrewCab59
1/2 ton status
Cummins 3.9
What info do you need ,I can help with the parts I have a complete P 30 .
ask away.
3.9 can get up to 25 mpg with good power,say 300HP
A 6.2 or 6.5 can't come close and won't last as long .
(My bother is doing a 3.9 in his 84 Blazer,he just getting parts together ).
P.S my shop is moving to knoxville, TN
CrewCab59
What info do you need ,I can help with the parts I have a complete P 30 .
ask away.
3.9 can get up to 25 mpg with good power,say 300HP
A 6.2 or 6.5 can't come close and won't last as long .
(My bother is doing a 3.9 in his 84 Blazer,he just getting parts together ).
P.S my shop is moving to knoxville, TN
CrewCab59
BowtieBlazer
Diesel Powered
crawlink5 on this site just finished his conversion in a 79 blazer, we got it on the road yesterday.
I'm going to be dry fitting mine with the body on soon as well in my 86
here is a dyno curve on the 4bt.
Ease of swap obviously goes to the 6.2 or 6.5 as they are straight bolt ins.....
here is a pretty good 6.2 build
http://community.webshots.com/album/286393940AoOzqp
I'm going to be dry fitting mine with the body on soon as well in my 86
here is a dyno curve on the 4bt.
Ease of swap obviously goes to the 6.2 or 6.5 as they are straight bolt ins.....
here is a pretty good 6.2 build
http://community.webshots.com/album/286393940AoOzqp
Last edited:
crawlink5
1/2 ton status
I certainly like the engine! If I can just get my brakes working...
grimjaw
1/2 ton status
crawlink5 said:
To hijack my own thread....Hydroboost brakes are your friend.
CrewCab59 said:
I am interested in what is needed to get 240+hp 450+tq and keep 25+mpg. Is this using comman parts or do you need that rare, only made 30 years ago, part?
BowtieBlazer
Diesel Powered
Yes indeedgrimjaw said:
Basically turning up the fuel pump starts barking out the tq and HP, however that starts = fuel mileage loss, I'll have to find the spec sheets I had printed, I believe the 4bt that I saw with simillar numbers to what you posted was down in the teens on mileage. Still beating a gas motor though.grimjaw said:
You can also look at interchanging turbos with a 6bt for a quicker spool and more low range pep, they make higher flow injectors, pumps, etc etc......by no means is the block, internals, or compression a limiting factor.
What type of injection pump is on these 3.9's? Are they rotaries like the VE 5.9's or are they inline pumps like the P7100 on the P series?
If it's an inline bosch pump you could maybe modify the fuel plate for more fuel just like the 12v 5.9's are capable of.
An HY35 quick spool turbo like what is on my '01 Ram auto would work perfect on the 3.9. the HY is good for basically 300HP and spools quick. The HY doesn't leave much room for fuel on the 5.9's and you could pick up an HY for cheap because of that reason, they get tossed if you want to make more than 300HP and actually tow at the same time.
If it's an inline bosch pump you could maybe modify the fuel plate for more fuel just like the 12v 5.9's are capable of.
An HY35 quick spool turbo like what is on my '01 Ram auto would work perfect on the 3.9. the HY is good for basically 300HP and spools quick. The HY doesn't leave much room for fuel on the 5.9's and you could pick up an HY for cheap because of that reason, they get tossed if you want to make more than 300HP and actually tow at the same time.
BowtieBlazer
Diesel Powered
its a rotary pump on the 3.9's the inline ones for the 4BT are $$$$$$$$
