Lowering compression,,,

[R.O.R-2.0]

WHY do you need to lower the compression?

these engines are forgiving, even with 24:1 comp..

just remember, its not the BOOST that kills these engines, its the DRIVE PRESSURE..

if you can keep your drive pressure low, you can boost as much as you want..

[TUFFY]

Is drive pressure the pressure in the exhaust manifold before the turbo?

[8v-of-fury]

Yes sir.

Check this truck out, they took it from 170 whp, to 972 whp and like 55 psi of boost on compounds.

I have kept up with the article since they started back in 2007, and one of their huge issues was when they hit a certain spot of power they were having like 125psi manifold pressure!!!!!!!!!!!!!!

What they do is run a huge manifold blow off that is open when WOT so it bleeds some of the manifolds excess, and still allowing the turbos to sustain ~55psi..

Drive pressure killllsss, more than crack.

[TUFFY]

I was planning on a pressure gauge in the exhaust manifold. The problem is with a bunch of gauges I probably won't have time to look at them when pulling. Wish I had a engine dyno to dial it in on.

[TUFFY]

Hi, My 1.9 head gasket showed up today. Hopefully with this gasket and ARP studs I won't have any gasket problems. Should the block and head be real smooth with this gasket?

[TUFFY]

what turbo do you plan to use?at what pressure?

Going to start out with a T3/T4 and hope to be around 40 psi or more. Might end up with two turbos down the road. Don't know if a opened up stock pump with main spring shimmed will be enough fuel to get me there though.

[8v-of-fury]

A 9mm pump will push quite a bit of fuel

[TUFFY]

A 9mm pump will push quite a bit of fuel

That sounds promising

[dodger21]

Yes sir.

Check this truck out, they took it from 170 whp, to 972 whp and like 55 psi of boost on compounds.

I have kept up with the article since they started back in 2007, and one of their huge issues was when they hit a certain spot of power they were having like 125psi manifold pressure!!!!!!!!!!!!!!

What they do is run a huge manifold blow off that is open when WOT so it bleeds some of the manifolds excess, and still allowing the turbos to sustain ~55psi..

Drive pressure killllsss, more than crack.

Talking about the old Cummins? Project Rust Bucket?

[8v-of-fury]

Project Rust Bucket! yes, that was the one. An amazing build. Started with 170bhp, ended up with like 927?! And over 22mpg up from 16.

[Alcaid]

It is neither IMP or EMP that blows headgaskets, it is PCP. Boost, fuel amount and injection timing are the biggest contributors, not EMP as stated over here.

[dodger21]

Project Rust Bucket! yes, that was the one. An amazing build. Started with 170bhp, ended up with like 927?! And over 22mpg up from 16.

I know the build very well. Was on my main forum asking for opinions before he started.

The reason for the BOV nitrous. With the timing he needed, and the amount of N2O, the BOV blew pressure around the tiny (62mm is small for the Cummins, TINY for 972hp) turbo so it wouldn't explode in a spectacular fashion. No compounds on that truck.

Here are some specs off the top of my head.

Reg Cab Long Bed 1st Gen Dodge
47RH built OD trans
Gearvendors OD making for double OD
3.07 rear axle (was originally a 3 spd non OD auto truck)
5x.025 injectors
14mm H&R
VE Pumped
62/65/14cm turbo
32" rubber
25-27mpg running 65-75mph
Runs around, I believe, 1300rpm @ 55mph with both OD's.

[R.O.R-2.0]

It is neither IMP or EMP that blows headgaskets, it is PCP. Boost, fuel amount and injection timing are the biggest contributors, not EMP as stated over here.

high drive pressure helps cause high pcp...

[Alcaid]

It is neither IMP or EMP that blows headgaskets, it is PCP. Boost, fuel amount and injection timing are the biggest contributors, not EMP as stated over here.

high drive pressure helps cause high pcp...

You are just guessing, and you guessed wrong

For EMP to blow the head gasket EMP would need be in the order of 3000psi+, not going to happen!

[R.O.R-2.0]

It is neither IMP or EMP that blows headgaskets, it is PCP. Boost, fuel amount and injection timing are the biggest contributors, not EMP as stated over here.

high drive pressure helps cause high pcp...

You are just guessing, and you guessed wrong

For EMP to blow the head gasket EMP would need be in the order of 3000psi+, not going to happen!

so, your telling me that if the engine has 50psi drive pressure, its going to have the EXACT SAME PCP as a n/a with NO drive pressure?

i find that HARD to believe...