4BTA final adjustment

[TKingsbury]

I don't know about anyone else, but I'd like to see a pic of the whole truck. Is that possible? Thanks

Travis. .

 

[driverswanted]

Here's the truck photo. This is the photo from the seller I bought it from. The only difference is that it now has the Ram's head on the hood.

 

[TKingsbury]

Nice lookin truck.

Travis. .

 

[driverswanted]

Thanks travis,

I had some 235/75-15 tires on it for a short time. Sure was ugly with the lift springs and the small tire. I could not send any pics when they were on. Even had co-workers laughing :-laf about the small tires. Only problem now is that I have one bent rim on one of the 32" tires and the tire noise caused by the bend rim Oo. is driving me nuts. Hardly any engine noise at this point since I used upside down roof shingles on the floor.

 

[driverswanted]

Kinda cool driving the Prospector around. Hardly any shortbed Ram Prospectors around this area of the country. I now have the Chromed Cummins Diesel badges below the POWER RAM badges and people are really interested when I tell them about the fuel economy.

 

[TKingsbury]

I know what you mean about small tires. Last week I put stock 235/85r16s with center hubcaps back on my truck so I can make a trip towing in the mountains this week. It looks cool, like a stock high boy, but it is a tad odd being so tall.

Travis. .

 

[driverswanted]

I hear you Travis. I had better pull with the small tires because the rpms in 5th and 65 mph were right where the turbo would spool up rapidly. The fuel economy is going to suffer too with the bigger tires because when slowpokes in front have to do 55-60 mph I have to keep it in 4th gear and on the downhill side of the torque and economy curve. It sucks having the 3. 23 gears. I'd like to have 3. 54's or 4. 11's front and rear. I just don't have time, knowledge and the tools to make that change right now.

 

[TKingsbury]

You are probably in the same place I am with mine. With the 35s you can't use 5th until 65 or so without it working kinda hard. In California it is a no-no to be going over 65 while towing . I also had very poor power in the mountains. I'm liking the small tires, the truck feels really peppy and isn't working nearly as hard now. My empty cruise EGTs are down nealy 200 deg! I'm hoping for a large improvement in the hills, 3rd gear @ 45mph sucks.

Travis. .

 

[driverswanted]

What's your rear ratio? With my 32" tires it's not quite as bad as that. With the 3. 23 I can run at 60 mph in 5th without too much complaining from the engine unless I hit a hill. At that speed there really is not much acceleration; have to be patient or drop to 4th and take the pedal to about 3/4 throttle for the turbo to spool up.

I like the smaller tire performance also. I get nice spool up from about 55 mph in 5th gear. Towing with the small tires is good also. Fuel mileage is slightly better too because I don't have to run in 4th behind granny or grampy who do 55 mph or less.

 

[TKingsbury]

My gear is 3. 54, but I am dealing with bigger tires. I run 35s (34"tall) normally, and now I am running 235/85r16s (31" tall). If your tires are 32s (advertised), they are probably like 30-31" tall. If this is the case, I think you'd like 3. 54s. I am really liking my current set-up. Just filled my truck today, first full tank with stockers, and my mileage was 18. 7. I have cooler EGTs, better giddy-up, better mileage, and the cool bone-stock look (lots of older guys stare now), so I am half tempted to keep it this way for a while .

Travis. .

 

[Willys]

Any updates?

 

[driverswanted]

Geeeeze the fuel prices! I backed off my full load fuel setting from 3/4 in to 1/4 turn in. I think it's running better than 25 mpg but I did it in the middle of a tank run. Just filled up yesterday. I'll let you know after I run most of this tank out.

Any fuel economy enhancement tricks that anyone else tried on first generation engines?

 

[MicroOutlawRacer]

Timing and bigger injectors helped the economy in my 92. Almost 1. 5mpg hand calculated with both of them. The injectors I have are F1 EDM's but I don't know if he will make anymore. Hope this helps.

David

 

[Willys]

Veggie oil conversion? Nice to see you getting the efficiency back up there, I love seeing successful conversions like this.



You can't say much about your mileage being low, my CTD is in the 15-20 range, probably on the lower side of that with all the stop and go driving I do.

 

[driverswanted]

Yes. I've been thinking about running SVO. Looks like the hardware will be about $500. The tank would have to use up the storage space behind my seat. I never did find good information on the injector efficiency of the different brands. Every piece of information seemed to be how to get more power and smoke. I bought the Bosch 190's not knowing if they were really more efficient than the 4BT standard ones. Also went with an advanced timing that Pastor Bob recommended and figured I could not do better than his expert knowledge on those injectors.

 

[dieselcruiserhead]

Interesting reading this thread... I have been tweaking my 4BT fuel pump and at near settings to yours I have been hitting 13 psi to 15, even 17 very occationally with just my little H1C so something must have been off with your intercooler, even the Saab 900 one. And even stock injectors. . My guess is that honestly maybe you still had an air leak somewhere?? Even with the restriction I still think you should have had higher boost pressures but perhaps I am wrong... I only say this because my Volvo 740 intercooler is much larger and should have more restriction but I have been able to hit these numbers easily. I can't imagine how the intercooler could have reduced those number that much unless there was some drastic restriction but i can't imagine how??



I am in the middle of building a WH1C turbo non wastegated 12 cm housing and I already have the 190 injectors. It ran just great but due to lack of a preheater I am pretty sure I blew or altered the head gasket this winter using ether. . You guys have probably read all about this on the 4BT yahoo group (I am "Andre"). Anywhoo, first I thought it was injectors and bought those. I now think my stock ones were probably fine because they changed very little. eventually - even though I never did do a compression test (which may be inevetable... I dunno) I determined it was a head gasket... I did do one small wheeling trip immediately after getting the head gasket in and it seemed to do great. But I noticed a weird whine/noise from the trubo. I also noticed some oil in the air tubes and pulled the turbo apart today actually and noticed oil in both the exhaust and intake so seals were blown. So since then I haven't driven it and have been waiting for the right parts to arrive to get the WH1C in (should arrive tomorrow or Weds at the latest - I can't wait!). And we'll see. When I had the head off I also "bumped" up the timing a little bit too. I seemed to notice that I cannot get as much boost with the timing advanced but perhaps I am wrong, too early to tell. I am very excited to be on TDR. . We have something like 200 people on the 4BT list, I can't believe it... I have wanted there to be another (free?) board with good 4BT info but good advice is rarely free as they say Anywhoo... Congrats on your higher boost pressures, it should be a rocket ship! I hope I get similar, I really want to wake this giant back up, I feel like it's been asleep since winter (when I believe I first affected the head gasket)... . Sorry for the long winded message here...

 

[driverswanted]

Dieselcruiserhead,



I here you on the boost numbers. I was up to 19 psi at one time but backed off the full fuel recently. I did a compression test early on and uncovered one leak. The only thing I still want to check is whether my waste gate is fully shut. I took off the boost feed to it because I was not in any eminant danger of hurting anything at 19 psi. It's hard to get to my mounting bracket for the diaphragm unit that opens it. I may be loosing some boost there and don't know it yet.

I also suspect my boost numbers are a tad low because I'm not generating good rpm's with the 3. 21 gears. I have been testing some leaner settings recently.

This weekend I change to 3. 55 gears, replace a howling pinion bearing and a bent axle shaft. I think the previous owner was doing some cliff diving or something and bent the axle. I would also like to try some LT245/75-16 (31. 5") tires along with the 28" tires. The 28's should give me simular rpm vs speed numbers as Steve Graham's Scout.

The other thing I'm going to try is move back to the stock injectors for a short period to test for fuel economy on those vs. the Bosch 190's. I know the Bosch 190's need more retarding I think it was and I've noticed some excess unburnt fuel (white) out the back on some hilly runs.

Have you done any testing to compare the Bosch 190's against the stock injectors for fuel economy differences?

 

[dieselcruiserhead]

I havn't done much testing with the Bosch 190's because I replaced them before I figured out the head gasket was blown. The mileage should be pretty similar I think though... Not sure, maybe a hair worse. When I get everything back together I'll start to check for mileage. I noticed as you are aware that the larger the load, the higher the boost numbers... I do think that gearing affects this but I'm not sure it's such a big idea. I run my 35's with 4. 10s and it's probably a similar overall feeling to what you have with smaller stock tires but I haven't given it much thought and the ratios are about right. But the larger "load" of the bigger tires might increase boost pressures, I dunno... Sometimes I wish I could go a little faster but 85 mph is actually pretty good Since I started checking my mileage this spring it's been much worse than anyone elses, but again I think I've had some poor compression issues for most of the last year even though I have thousands of miles like this. If feels much better already though but in only the quick little trip I took this weekend with the head gasket replaced. Anywhoo, I am hoping to be back in the mid 20's which I was when the truck was completely stock and a 3' 3" diameter straight pipe as my only exhaust. Even though I have a 3" mandrel bent, it restricted the exhaust quite a bit and I lost mileage and power versus the straight pipe I ran for several months. . The exhaust suprizingly did not quiet it much either. I should have forked down for 4" but the difference was about $800 for custom 4" or $175 with a flowmaster for 3". . So I went with the 3"... Hopefully this new turbo will make up for the lost pressure I got from the exhaust. Bone stock it would power my truck up the grades in 5th with that exhaust setup and everything in good working order... Hopefully this new turbo can make up for some of this loss. My mileage was in the 20's easily back then, probablyh more like 25 actually with this set up... But for most of the last year its been in the high teens and I simply thought it was the injectors going bad (and is why I replaced them with the 190's), not that I actually had a mechanical issue. I'll definetely post mileage, EGT, and boost info when I get everything back together... I have (I can't believe it) lost my original piece of paper with my original fuel settings so I have no idea what is stock any more, just a guestimate... I am currently over smoking and need to increase the pin. Star wheel is two full turns away from being completely engaged. Full power screw is about 2 full turns from all the wayh in. Bummer about this one because it seemed to make a big difference, even a 1/2 turn was a big deal if I remember correctly...



Andre

 

[driverswanted]

Are you at about 1700-1800 rpm at 65 mph? Not sure if you mean you have a true 35" tire but the calculator shows shows the above numbers with 4. 10 gears after the nv4500. I'm close to 1600rpm @65 with my 3. 21 gears. That's why I'm going to 3. 55's this weekend.

 

[dieselcruiserhead]

One thing I figured out and I am *absolutely positive of this* is that the actual diameter of tire that is posted is the actual diameter of the tire. It reads small with a tape measure because of the weight of the truck and that's all, but the diameter of the actual tire is still the same when the vehicle is spinning. I learned this because I kept putting out calculator numbers with the "small" size then the actual posted size and the posted size (34. 8" or something like that, for a goodyear MTR), is right on the money with the speedo and my calculations. For years there has been this misnomer aobut "true" and not true tires but most of it is BS...