4BTA final adjustment

[EColeman]

I was just curious if you knew what you might be getting for fuel economy? You recently got me thinking (was going to do a toyota conv. ) about putting my 4bt in my 87' Ramcharger 4x4 5"lift 33" but thought the 4bt might be working to hard to get some good mileage numbers. (got to better than the bread box it's in now though) I see LAlessi's rig gets some impressive numbers for it's weight and not being so areo-dynamic. Wonder if or how much his mpg went up w/the 35's?...

 

[driverswanted]

Forest,



Yes it is the paper thin inter-cooler. But I think it is more of a restriction maybe than a danger of bursting. I contacted 3 people who have had experience with them and 2 of the three say they have been up to 25 psi. Each tube is only 1" by about 1/8" I. D. I don't have a total count on tubes handy. I fully intended to but two of these in parallel but ran into some time and fit problems with the other one so I abandoned using it. I will buy a Dodge, Ford or NPR intercooler when I get back from my fishing trip. I may even have time to by-pass the intercooler before the trip. I just need to sneak under the frame rails with an adapter section. I have plenty of stainless 2. 5" elbows, couplings and straight section to do this.

Just went back out and looked at the boat towing run max numbers. Boost max is 14. 8 and temp was 1218 F. My boost is measured after the intercooler like it should be.



Ecoleman,



I'm holding off giving fuel consumpsion numbers until I dial this thing in. It would also be better if I waited till I got into my regular driving habits (after the fun factor period). It does burn rubber in 1st now BTW since I turned up the Full load screw. I guess it's time to turn down the smoke screw. I didn't realize how much smoke it was until I saw it dimming the headlight beams of a car behind me this evening. The 4BT with the VE pump will be getting the best fuel numbers when the rpm's are about 1650-1800 at highway cruising speed.

I remember someone here posting good fuel numbers; 30 plus with the 4bt in a one ton. I will turn mine back to an economy setting after I get back from my fishing trip.

 

[driverswanted]

Some 4BT mpg numbers

I got back from my week long fishing trip. After turning up the fuel settings I'm getting better mileage. It's around 25-26 mpg now. Also have the stock sized 235-75-15 LT tires on now that make it more driveable. Found out I have a 3. 23 rear end which made driving the 32" tires somewhat tough at 55-60 mph. Still have not turned down the low to mid range smoke after I turned up the full power screw. I suspect the mileage will get even better once I do that.

Hauled a full load of wood in the back end yesterday. It sure loves to pull up a hill! I barely move the pedal. The boost response is so much better than the '91 one ton 6BTA but then I have not turned that one up. It runs up to 8-10 psi of boost on grades and is happy as a clam there. It runs up to about 12-13 psi when I accelerated around a semi on several grades. It jumped from 65 to 73 mph quickly on those grades with the full load of firewood in the back. All I can say is at this point it was worth every minute I spent these last two years on the conversion.

In a previous post I complained about engine lugging but that turned out to be a driveline mis-alignment. I just needed to unbolt the trany and run it down the road to let it seek it's left to right center, then rebolt it down.

Still don't get the engine above 156 F. Wondering if the economy would get better if i blocked off some of the gasser radiator I used. I would like to switch to an electric fan later too.

 

[HoleshotHolset]

Weird how LAlessi's much heavier and taller tired/geared truck gets about the same mileage as this 2wd Ram...



Matt

 

[driverswanted]

I do have the fuel turned up to tow a load with. What did he do with his fuel settings? I know I'm not at the most economical settings possible. BTW it is a 4x4.

 

[HoleshotHolset]

OK... that makes sense.

I'm not sure what LAlessi did with his fuel settings... probably left them as-is, but I'm not sure.



I wonder what a 2wd light little pickup would get for mileage with tall gears and a lean tune...



Matt

 

[driverswanted]

I'm still getting plenty of smoke in pull away and mid range accelleration after turning the diaphram smoke screw back up to what was the original setting. I thought that was all you had to do to cut the smoke back after the full load screw was turned up. Maybe I just have to take it out even further?

You see that the rock crawlers are getting real light in their construction. I wonder when someone will take one of those tubular frames, like a beafed up dune buggy, put the 4BT in it and try for a new 4bt fuel mileage record. Should be able to get up to upper 30's pretty easy.

My brother saw one of the zero steering radius lawn mower manufacturers is putting in a 3 cylinder turbo charged diesel. He said the head is only about 10" across the three pistons. Sounds like someone should try this in a motorcycle. It put out something like 30 hp but I did'nt catch any torque numbers.

 

[Willys]

Everything I've heard from Lee so far is that he has not turned the pump up at all. I could be wrong though...



There is a guy on the yahoo 4bt list who has a Dakota 2wd, with a 4bt and TH400, with 2. 5:1 axle gears. I think he gets around 26 mpg, and the engine is at the stock power rating. I suspect it would get better mileage with a stick, overdrive and lower gears, but that is a lot more money to pour into a truck that is just a driving vehicle... He has 90k miles on the conversion, last I heard.



Drivers Wanted- that's a great project- I'm glad to see it complete. Did you have to spend much to get the hy35?



Some diesel motorcycle links(I must be a dieselhead to have these bookmarked, I'm not even into bikes... ):

http://www.f1engineering.com/diesel bike specs.html

http://www.peace65.freeserve.co.uk/Pictures/diesel.htm

 

[driverswanted]

Thanks Willys. I know the guy with the 2WD Dakota. That's Jonathon. He's given me most of the inspiration to do my conversion. I'm not an auto mechanic and he helped me through many e-mails over the last two years. He was on a road trip to the east coast area last year and he stopped by my house. He let me drive his Dakota. His main goal was to put in an engine that would last for several hundred thousand miles. He does not believe in turning up H. P. He does not even like to talk about it much. It goes against what he believes the diesel was made for;that being durability. The last thing we talked about was that the truck body was not going to last anywhere long enough. He'll have to transfer that engine to several trucks over it's lifetime probably. He also did up a Gamma Goat with I think a 4BT and he was also recently finishing up a Burb with a 6BTA.

Yes. I found the Hy35W cheap on eBay from someone who was changing over several trucks to I think banks turbos. They must have come from someone's truck who felt the HY35 was chocking down their potential boost. I think I ended up paying just under $200 for mine.

I'm going to disconnect the wastegate and see if that changes anything. I want to see if my intercooler is restricting my top end boost and forcing the wastegate open.

 

[Willys]

Thats the guy, I couldn't remember his name off the top of my head . We've emailed a few times, and I gave him the link to the yahoo list... A really knowledgeable, helpful guy Jonathon is. I vaguely remember hearing about the gamma goat. That's an interesting project. If I remember right(seems my memory has been failing me lately), the Burb is a perkins, don't know the model #.



That's a lot less for a hy35w than I expected. Do you think it is worth it in the amount of performance gained? Are you able to use a larger intercooler?



I'm planning a 4bt swap into a cj7/scramblerish jeep. I pull a landscape trailer fairly often, but it is usually in the 3-4k lb range- no more than your boat I'd say. The jeep will probably weigh the same or less than your truck. I think I'll use your engine as a template... .

 

[driverswanted]

I don't have a reference on what the H1C would do on teh 4BTA compared to the HY35W. I expected fast spoolup with the HY35W because of it's smaller exhaust impeller surface area. It is faster to spool up than my '91 one ton 6BTA but then I never turned that engine up so maybe it's not much of a comparison. I have not removed the Saab intercooler yet but plan on by-passing it ASAP to check the effects of that restriction. I have to cut some more 2 1/2" stainless elbows and straights for the by-pass and I think I can work it in between the fan and engine over the rails. A new clutch slave cylinder has to go in first though. It's not fun loosing your clutch disengagement while driving

 

[ezcurra]

It's not fun loosing your clutch disengagement while driving

My clutch linkage fell off one night while driving my 78 Cherokee (full size) and I spent the next couple of months driving with no clutch. I would start in 2nd gear (1st if facing a hill), shift gears with no clutch, and with a first gear of 6. 4:1, I could crawl towards red lights hoping they would turn green by the time I got there, so I wouldn't have to restart the engine. I could even parallel park with no clutch :-laf



Two months later, during a walk, I found my clutch linkage right where it fell off

 

[driverswanted]

Removed Saab Intercooler

I just finished a run beer run without the Saab intercooler. That intercooler was a significant restriction. With nornmal acceleration conditions the boost climbed from about 3 to 4 psi before in 2nd gear to about 6 to 9 psi after the Saab intercooler was removed.

Now the fun information.

With medium acceleration in 4th gear from about 40 mph I hit 10 to 13 psi boost easy. Under hard acceleration from 40 mph in 4th gear I got a peak recording of 17. 5 psi when I was near 65 mph on a level road. I could not generate that same peak boost in 5th gear because I had to watch my max speed ( i. e. below 70 mph) with the road conditions; meaning I was not on a long straight road.

I will perform the same test with a load (~2 tons) in about a week. That's when I expect the max boost numbers will climb over 20 psi.

 

[AKAMAC]

driverswanted,

What aftermarket LS front diff are you running? Are you using manual hubs? Mike

 

[driverswanted]

DONO what brand is in there. I'm the third owner and the first owner put the limited slip in there. The guy I bought it from lost contact with the person he bought it from and he didn't know what he put in.

The hubs are Warn manual lockouts. I hate automatic lockouts. I should say I hate GM electric 4x4 engagement. I had a GM with electric lockouts and I won't own another vehicle with their tin can motor and cheap encoder feedback electric lockouts again.

My apologies to Rbalcom. We were emailing each other about getting a pressure drop reading on the Saab intercooler and I could not find my 30" h20 DP guage to test it before I bypassed it. I had just enough time on Sunday to change the tubing to a non-intercooler configuration. The bottom line is that a single Saab intercooler was a substantial restriction.

Has anyone posted boost numbers for various types of acceleration for the stock version H1C on the 4BT?

I guess really this calls for a dyno test. Maybe someone with the stock H1C can scan and post their dyno run and I can do the same.

 

[driverswanted]

19 psi boost on 4BT

I made a wood hauling run and a boat towing run this weekend with the intercooler by-passed. I was able to get to 19 psi with egt's at 1052 F. This was with a full load of firewood one foot over the top of the sides. The boat was pulled up a 3/4 mile long and ~60-70% grade hill hitting 1250 F on egt. The boat run did not get near 19 psi. I had to run the hill in 4th gear to keep the boost and road speed up.

 

[Willys]

how has your mileage been lately?

 

[driverswanted]

4BT Fuel Mileage numbers

I just finished a 30 gallon tank. I did not haul any loads with this last tankful and I'm getting 25. 3 mpg. It takes several weeks to get this thing empty. I was trying to run this tank without much rapid pedal movements and adjusted the pedal when i saw a significant amount of smoke blowing out. The full load screw seems like it can be backed out somewhat now from the 3/4 turn-in point I have it at. In the interest of ecomomy It can stand to be backed off on the amount of acceleration I'm getting right now. It's still able to spin the tires from a standing start.

BTW, I put the 32" tires back on after I refilled the tank. I want to see if the fuel mileage can be improved with lower RPMs at highway speeds. I took them off originally because it felt like the engine was lugging at lower speeds. Since I pulle those tires off I had done another driveline alignment and glued alot of roof shingles (excellant noise reducer btw) on the cab floor for noise control. It runs just fine now with the bigger tires. I had 4th gear around 35-40 mph and it ran just fine. I can hit my 10 psi boost alarm limit easily from there with moderate pedal input and it accelerated nicely.

While the rear end was jacked up I also verified that I do have a 3. 23 rear.

 

[Willys]

That sounds pretty good



Just out of curiosity, was that tank highway, city or a mix? If you want some quick testing I'd be glad to drive it for a few weeks for ya... .

 

[driverswanted]

It was about 90% highway miles.