Project: Turbo 250

[longbed67]

Well back into tuning again between when I am using the truck... After talking with kevin at CSU carbs, he convinced me to lock my timing out. so I have my timing locked out at 36 degrees, made a huge difference in drive ability .... I still am running pig rich though.... On a good note I know she will pull an 11,000 pound trailer and hardly blink an eye, I didnt even have to shift out of 4th gear going up hills to maintain hwy speed.

[2fiddy6]

Any updates? Love this thread.

[longbed67]

Well the update is I have my AFR numbers better and I have turned the boost up a little to 10lbs and it runs pretty nice, and it turns heads everywhere but I am pulling between 18 MPG on hwy cruises A far cry from the 25 I was shooting for. And I have put a total of 1500 miles on... Soo I am looking at doing a 4BT cummins swap into it and selling the turbo 250 motor and the 435 trans behind it...I have a solid 8k in receipts invested in the whole deal with all the extras so if anyone has any thoughts or realistic offers Im all ears!

[kikkegek]

oh man that would really be a loss for t he car...line6 with turbo is not that common...

how many rpm's you doing on the highway cruisin?

I tried all kinds of things to get mileage up on my Suburban...a lot of them I was told would improve mileage, but didnt, like:
- MSD 6AL
- bigger sparkplug gap
- cool air intake
- K&N air filter
- improve/modify timing setup (I tried base, mechanical, springs and vacuum)
- thinner oil (went from 20W50 to semi 10W40)
- right tire pressure
- dropped my idle rpm from 700 to 500 rpm (I drive on propane, and that idles very steady on low rpm)

the two things that really helped:
- replaced the flex-fan with an electrical fan setup (10-15% MP gain)
- replaced TH400 with TH700R4 (dropped highway cruise from 2900 to 1900 rpm 0_o and increased mileage by 25% from 9.4mpg to 11.8mpg) but it only improved on highway..the lower gears of the TH700R4 didnt improve citydriving any bit

so if you are looking for improving mileage:
- drop rpms
- lose any parasitic drag on the engine if possible like flex or fanclutch fans

realy great build though, love your car!

[longbed67]

I am turning 2000 rpms at 60 miles an hour. I don't have any losses with a torque converter As I am running a manual transmission.and I don't have any losses in a Flex fan.

[slick copper]

Aw man. Really hate to hear you're thinking of getting rid of the inline six. I've actually just bought some parts for mine off a friend at work. Offenhauser 4 barrel intake (new in box) with brand never opened throttle linkage kit, machined and rebuilt head, TRW flat top pistons, and a cam and lifter set. Hope something pans out for you.

[longbed67]

I have a lot of time and research and resources into this project, however I feel as though I would be happier with the low end performance of the diesel. As well as the fuel economy. If anyone is interested in the motor, ignition, fueling and turbo/ exhaust system with the the transmission and clutch assy. make me an offer.

[Russ_the_truck79]

I thought that was your engine i saw on ebay! man if only i had the money... hate to hear it go i stalked that build big time.

[longbed67]

Yes the engine is up for sale. I picked up a 4BT cummins yesterday and am backing it with an NV4500. If I had $10 for every time I heard "if I only had the money" the engine would be sold right now lol no joke, I have received so many calls and emails about it stating they had followed the build and hated to see me sell it, but $3500 is a steal for that setup... even though I am going to lose my tail on the inline 6 I had fun with the build and enjoyed it, now its time for me to play with this little diesel!

[swamp rat]

If you were local I'd consider it, but i admit i enjoy doing my own build too.

[JustCallMeDrew]

Any updates....also i was wondering if you could give me a parts list and a price estimate of turboing a 250 just the necessities!

[PushnFords]

Did you get the engine sold?

[Reining]

Originally Posted by longbed67

Well got a lot of little stuff wrapped up this weekend...Buttoned up all of the little bolts up front, got the meth injection tubing secured drivers side engine bay wiring harness finished up, the front splash apron on, in the back I got a whole bunch done as well. I took out the oem shock tower crossmember and got my gooseneck hitch cut to size and set in place I also built some shock mounts and figured out a mounting system behind the axle outside the frame rail that still uses the factory sized shocks and has full travel from the axle touching the frame rail to past my full bag height! I also secured all of the brake lines properly so they do not get pinched like it looks like in the shock picture. And I do have new shocks, I just used the old ones to mock up with

Have you got a chance to run the gooseneck yet and is there any chance of seeing the inside of the bed?

[longbed67]

Well time to revive this and post all the new mods.... to quick reply yes I have had a chance to pull a goose neck and trailer weight was 25,000 ish lbs and pulled it like a champ with almost as much control as my 1 ton dually duramax does. I can get pictures of the set up after I get some other stuff.

[longbed67]

Well the first major change was switching from the turbo'd 250 motor and 4 speed to a Cummins 4BT Recon motor and matching NV4500 trans with a twin disc mating them. I have since upgraded the OEM turbo from a 18cm H1C holset with a 42mm compressor to a 12cm H1C with 54mm compressor so a 40% upgrade in turbo size, I am currently fabricating a ram air intake for the turbo to further increase efficiency, and have advanced the motor timing. I am also currently upgrading the entire air suspension from our own control system where I ended up having some valve issues to a full accuair e-level system.

[1972RedNeck]

Originally Posted by longbed67

Well the first major change was switching from the turbo'd 250 motor and 4 speed to a Cummins 4BT Recon motor and matching NV4500 trans with a twin disc mating them. I have since upgraded the OEM turbo from a 18cm H1C holset with a 42mm compressor to a 12cm H1C with 54mm compressor so a 40% upgrade in turbo size, I am currently fabricating a ram air intake for the turbo to further increase efficiency, and have advanced the motor timing. I am also currently upgrading the entire air suspension from our own control system where I ended up having some valve issues to a full accuair e-level system.

You ought to go over to 4BT Swaps and do some looking into the Super HX30W...

[longbed67]

Pics

[longbed67]

Truck with 4BT now weighs 4420 empty on the scales.

[longbed67]

Originally Posted by 1972RedNeck

You ought to go over to 4BT Swaps and do some looking into the Super HX30W...

I have looked at this, however with this setup i am spooling instantly off of idle, get 20lbs of boost without pulling or having a load on the motor and mid to upper 20's in the boost when under a good load. And the best part I get 24 mpg pulling a trailer and 36 city and 38.4 highway when empty, I this is consistent fuel economy over multiple tanks of fuel.

[longbed67]

Originally Posted by Reining

Have you got a chance to run the gooseneck yet and is there any chance of seeing the inside of the bed?

Here ya go! Frame is reinforced on the outside and has bottom angular bracing tying it all together.

[longbed67]

Here is the new turbo as well.

[Palf70Step]

Nice, very nice.

[longbed67]

Well time for the next motor. The little 4bt wasn't quite enough for me. I am currently building a 12 valve. More details of the motor specs coming.

[kikkegek]

booya!

looks nice

[Palf70Step]