more boost?

[prototech]

I have a 16cm housing on the stock H1C turbo and after some pump adjusting I still only get about 20psi of boost, I read all the time of you guys getting 30psi and better, any ideas on what I can do to get more boost? I have an auto trans and I was wondering if any one else with an auto trans is getting over 20 psi? thanks,

Proto

 

[JLEONARD]

Are you sure that there are no leaks in your intercooler or plumbing?

Sometimes it pays to check out the basics.

Jay

 

[dpuckett]

Proto,

If you still have stock injectors, 20-24 psi is about all you can expect without lots of smoke, high EGTs, etc. Most of the high boosters run either stock nonIC injectors, or aftermarket injectors. The stockers in mine and JLEONARD's et al, flow more than the PWs, or at least equal to them. Takes fuel to make enough exhaust to move the turbine blades. BUT... ... boost doesnt necessarily equal power. I was making 40+ psi with a 12, but I seem to have more power and set me back in the seatability with the ported 18, but peak out about 34-36psi.



Daniel

 

[sparks57]

Yep, 25 or so PSI is the most you can get with stock injectors and a stock h1c.



I get 30+psi, but I have a ported/balanced/hybrid turbo.

 

[phillips5]

I have a 93 ext dually auto stock inj. and get 27 psi. I know it would be more if it was a stick. our torqconverters don't put much load on the engine so it can reach governed speed with out much fuel. So the next trick is to raise goverened speed to 3000 Than you will see the engine be locked to the wheels a little better and the boost will be higher,the truck will be faster,lauder,and more fun

 

[sparks57]

Yep, high idle helps a lot, but best when combined with a governer spring.



Remember, it's not good to go down more than a turn and a half on the full fuel screw with stock injectors. That's assuming IC.

 

[J.R. Adkins]

I see 27 psi @ wot with the 93 with stock injectors. I only put 1. 5 turns on the fuel screw. Should this be this the limit with the stock trans?



J. R.

 

[prototech]

I just put a used intercooler in a little while ago to replace my leaky one, I pressure tested it before I put it in but I have'nt tested the whole system. The thing that is weird is that I was getting about 15-18 psi before with the leaky IC so It hasn't gone up much. the truck runs out pretty good, I just wonder if it would be that much better if I was getting 5-10psi more?

Proto

 

[Stomp]

I don't know if this may be your problem, but I had my psi go down to about 20 one time with my stock h1c16 housing and I replaced my lift pump and it was back to 30-32 psi. I then changed the housing to a 12 and saw my boost go up to 34 at 4000ft above sea level to about 40 running on the coast. Thats before I was told that I was putting bad boost into my pickup, I believe that my mechanic said anything over 32-34 for a stock h1c wasn't doing any good. I ran 340/790 on the dyno,but that was with the propane on. It was only good for about 17hp and 50ftlbs of torque. I have since upgraded to a Piers Hx40/16 housing and I have it wastegated to 45psi I don't like to go that far because of a stock head gasket, but if someone wants to race I will hit the propane and take it up that far.



Stomp

 

[dpuckett]

Remember, it takes fuel to make boost. The lower you can run your CRUISE boost, the better off you'll be; less restriction, fuel usage, etc. But it is nice to see the 40psi gauge put to good use now and then. And since we're on the topic of restriction, boost is nothing more than resistance to flow. Hence CB Parker's (and eventually, my) desire to port and polish his head, manifold, turbo, and whatever else he can get ahold of. The more air you can flow with less restriction, the more efficient the engine becomes.

 

[Stomp]

Rodger that I need to do a little of that my self (Port and polish. )



Stomp

 

[sparks57]

Everything but the head is gonna be ported this month... as soon as I work off that damn "excessive smoke and lack of required exhaust components" ticket I got last week.



Porting and polishing is not something you should dive into, it takes patience and skill. Check out the sticky on porting.

 

[dpuckett]

You hotrodding again, making the ricer boys cry, CB? That sux about getting a ticket- fortunately, mine has a muffler, sort of. LOOKS like a muffler, anyway.



Daniel

 

[prototech]

Hey, so how do I check my lift pump pressure? and are there any aftermarket upgrades? If I end up replacing it I would rather spend a little more and get something better, faster, or more reliable!

Proto

 

[dpuckett]

lift pump

There is a fitting above the fuel filter housing. 10mm head, 1/8NPT fitting will fit into it, I believe. Tap into that and the other end to a fuel pressure gauge. Not sure of specs, hafta look around for that one.



The LP I got from Cummins last summer had the same Carter number on it as AutoZone, O'Reilleys, et al. The lift pumps on the mechanical engines dont have the reputation of the newer electronic ones, though the diaphragm can raupture and leak down the side of the block, and occasionally, into the crankcase.



Daniel

PS- will an oil pressure gauge work for fuel pressure? It is a liquid, though a slightly different consistency.

 

[jbolt]

53+ psi and an auto transmission... . oh wait you said H1C... . never mind