Engine/Transmission (1994 - 1998) HTB2/62 boost limit?

[JGheen]

Just wondering if anyone has any opinions or facts as to how much boost my HTB2/62 can take? I put an adjustable boost elbow on the wastegate hose a while back and right now I am pushing it to about 47# with my new fueling mods and new o-ringed head. Should I keep it around 40-45 and no higher or could it take more and go to +/- around 50#?? Smoke levels are clearing up over 40 lbs, so maybe higher is not better. If I can't/shouldn't go any higher, should I consider upgrading it to the 64mm compressor or even turn it into a SP66??



Joe

 

[Got Smoke?]

Joe I can't get mine past 42 WOT and I've got more fuel than you



I think HTT says as long as its under 50PSI its good!

 

[JGheen]

I don't know, I recently had my EDMs machined out more to flow more than your 370s do. And with the 'ol #100 plate in there, it really gets it down the road now. I guess no more than 50# is a good limit to live by.



Joe

 

[Got Smoke?]

I don't know, I recently had my EDMs machined out more to flow more than your 370s do. And with the 'ol #100 plate in there, it really gets it down the road now. I guess no more than 50# is a good limit to live by.



Joe

I wouldn't push it past 50psi to be safe!



I've still got one on ya big boy..... I've got my laser cut ADP DV's. So I'd say we're neck and neck in the fuel amount! :-laf

 

[Cooker]

Although I'm sure you would not damaged the turbo at 50psi one thing to keep in mind is that boost does not equal HP.



I did not do much testing with my HTB2/12 when I had it so I cannot comment on where the sweet spot is, but I'd bet that it will produce the most HP somewhere between 38 and 42 psi of boost.

 

[JGheen]

Oh I know boost doesn't always equal HP, I was just wondering what is a good limit to live by with this particular turbo. I too was thinking that around 40-42 like you suggested is probably a good spot to hang with..... I will try opening up the boost elbow screw a bit and look for a difference.



Joe

 

[Cooker]

I would be curious to know where the sweet spot is for this turbo with a 12 housing?

 

[JGheen]

Yeah, mine has the 14 so I would be no help there but if I ever get some good dyno runs in, I will run a couple times at different levels for comparison.



Joe

 

[Cooker]

Sorry my mistake. I just assumed that most order the HTB2 with a 12.

 

[JO'Leary]

I don't want to hyjack your thread Joe but while were on the subject of HTB2's, is anyone towing heavy (10k or over) with a 62/12. I am moving up to DDP4's and was thinking 62/14 but am concerned about surge towing.



Thanks Joe

 

[Forrest Nearing]

a bigger turbine housing would reduce surge, not increase it

 

[pwerwagn]

How are the EGT's with that much fuel Joe?? Are you running 4. 10's with the 37's??



--Jeff

 

[JGheen]

I don't want to hyjack your thread Joe but while were on the subject of HTB2's, is anyone towing heavy (10k or over) with a 62/12. I am moving up to DDP4's and was thinking 62/14 but am concerned about surge towing.



Thanks Joe

No hijacking, it's all good. On the subject of surging, I actually get a huge surge with only the load of the truck accelerating onto the freeway for instance shifting from 3rd to 4th and even 4th to 5th at full boost. I don't know any other way of reducing it, so I just have been living with it or backing off on the go pedal before I shift when accelerating hard. Not to sure about how it would be towing a load behind.



Joe

 

[JGheen]

How are the EGT's with that much fuel Joe?? Are you running 4. 10's with the 37's??



--Jeff

I am running the stock 3. 54s with my 37s and will probably keep that ratio right where it is cuz I think 4. 10s would kill my freeway mileage with the increased revs.

EGTs are not outrageous at all, highest I see going through all the gears except 5th is about 1400-1500*. This is with full go pedal to the floor through 2nd, 3rd and 4th gears. I still need to do some tuning with this #100 plate but haven't had time. I should know some more exact numbers maybe this weekend as I will have time to test out different boost levels on a short road trip I will be taking. But overall, my smoke is kind of heavy scooting around town and until I build some boost then it gets a little clearer. Good amount of haze at idle as well. I even played with different injector washer thicknesses and not much change in smoke. Right now I am running the thinnest washers to get that tip as close as possible to the piston bowl.



Joe