818 now with turbo and pics.

I would not have reduced the pipe diameter on the exhaust. There is a reason for it to be that size. Otherwise they would have used a smaller diameter to begin with...

More Pics... I am getting withdraw and I need a pic fix..

goldneagle said:

I would not have reduced the pipe diameter on the exhaust. There is a reason for it to be that size. Otherwise they would have used a smaller diameter to begin with...

Click to expand...

that is true but I'm not going for max power that this turbo can produce, if I were I'd do a 5" stack and start saving for a new motor.

put a few hundred miles on the truck this week towing around my 19.5k lb M270A1 and man she pulls so nice now even with the big tires. I can hold my speed on any hill and EGT's pre turbo are under 1200 and boost is about 10psi.

Jwaller if you would please let me know what you had to do for the swap, I can turn wrenches but I never done this kind of swap so I'm a little worried. I have a couple of bone yards around me so I can check with them on parts.

Thanks Vinny

Can we get pics of the intake?

jwaller said:

that is true but I'm not going for max power that this turbo can produce, if I were I'd do a 5" stack and start saving for a new motor.

put a few hundred miles on the truck this week towing around my 19.5k lb M270A1 and man she pulls so nice now even with the big tires. I can hold my speed on any hill and EGT's pre turbo are under 1200 and boost is about 10psi.

Click to expand...

the larger exhaust would lower the exhaust temps and possibly increase the boost. just my $.02

How does the engine fit in the engine bay?
Did you have to make new engine mounts?
Does the flywheel and trans bolt directly?

jwaller where's his turbo..? c'mon you have to mount one on his walker..then he can have one to .....a little t34 would work..!!!

hulk31st said:

How does the engine fit in the engine bay?
Did you have to make new engine mounts?
Does the flywheel and trans bolt directly?

Click to expand...

? hua?

I misread the first post. I thought it said you were installing a NHC 450 engine and turbo, but I see now--you're installing only the turbo from a 450. Duh.

?any more news on your mod jwaller, this is a interesting post as im about to by a 290 engine and want to swap over the turbo parts . ive spoken to a cummins man who says the turbo will drop egt,s so am i right in thinking that if one of the biggest problems the 250 suffers from is high egt,s if tweaked and worked hard resulting in piston probs then does the fitment of the turbo possibly reduce this risk if used sensibly with only minor fueling??.also in the cummins tm it says the 250 has a compression ratio of 15.8 to 1 which to me seems low for a diesel as the deuce 1c is something like 22 to 1 and most diesels are around 20 to 1.? is there any reason for the low ish comp ratio on the 250 or is it the norm for a big diesel motor? so consequently are the risks lowered when you turbo a lower compressioned diesel than they would be by turboing a higher comp one. ? any thoughts on this please?

martinsaunders06 - that is an interesting question. I would like to know the answer too.

I have not touched the fueling on the motor and it does seem to be running a much lower egt now than it did stock. I think these motors originally had lower compression to meet the hp/tq requirement that the gov wanted.

uncle same doesn't want the truck to have enough power to break the driveline. therefore the comp is low. I would imagine that with a lower comp is gave longer engine life. look at the longevity issues the multi has and how high the egt's and rpms are with that engine. there again comparing the two engines are like apples and oranges but you get the idea.

I would bet that in longevity testing, the turbo 250 would indeed last longer than a stock 250 bc the egt's are lower and thereby less stress on the heads, valves, and pistons all the while giving more power.

Ok, I have a new found interest in finishing this on my 816.. I did not plan to turn up the fuel either. I just need more air in the cylinders... (I live at 10,000 feet.) But now you tell me that the egts are lower as long as you leave the fuel alone, then ... I will do it soon.

Great job so far jwaller!

Any pics of the inlet plumbing?

thanks jwaller, that does make good sense so it is possible that this turbo mod used sensibly may not cause any problems. if the 250 was at say 20:1 compression to start with and turboed then it could be under some stress?. madsam this might interest you for in my cummins book they say that a non turbo looses 3% power for each 1000ft above sea level and 1% power loss for each 10 deg F (5.56 deg.C) rise in air temp ( rated HP taken at sealevel and 60 deg F (15.5 deg C) and a turbo only begins to loose 4% per 1000ft above "12000 ft".

that means it should be back at sea level with a turbo running here.

picked up the 290 turbo motor last saturday and will swap turbo bits soon but did notice it also didnt have any external fixings in lower block for the piston cooler nozzles just the same as the 250, you could see where they would be but the block was not cast for them.. this leads me to think if this 290 turbo dont have them then the lack of them in the nhc 250 is not the whole reason for the high EGT"S if tweaked . i once had a customer with a 1800cc/16valve vw engine which when driven/revved would run very hot and cause the exh manifold to glow cherry red hot= i found that someone had fitted a 1600cc crank which had shorter throw and the stroke was shorter which lowered the compression ratio causing the high EGT"S!. so if the tm is correct and the military 250 has a low compression ratio of only 15.8 to 1 then this low compression has to be a major contributor to the high EGT"S ? any one know what normal cummins civilian truck compressions are??

update?