what would be the best turbo to twin with the stock one. my friend has a silverbullet(dont know the size) off a cummins. would that be ok.

Too small.

You could use it as a top turbo though.

So what would be a good turbo to run with a stock turbo? Or is the stock turbo the problem?

In my humble opinion, the stocker is the problem. In a stocker single turbo the demand the engineers were trying to to fill the low end responsiveness as well as top end power.

Small turbos don't put out as much air volume as large turbos, and since it small ones move less air they spools quicker and are better for responsiveness (hit the throttle and go immediately). The problem is that small ones are not very good for putting out high hp at the top end as they just doesn't have the volume of air needed. The exact opposite scenario is true for big chargers, a lot of air means less responsiveness but higher top end.

What you end up with in the stocker are the design engineers trying to hit both marks, and you get a Jack of all trades/master of none design. You don't get the quick spool up of a small turbo and you don't get the high end hp of a large one.

Does that make sense?

yes after you explained it. i just thought i could save a buck and keep the stocker for now.

yes after you explained it. i just thought i could save a buck and keep the stocker for now.
You could.....Got Juice? had the MPI kit with stock LB7 IHI and the results speak for themself..

You could.....Got Juice? had the MPI kit with stock LB7 IHI and the results speak for themself..

Yup.
The MPI Kit for the LB7 Rocks.

11.9 capable on a stock CP3 with no lift pump, just tuning & Sleeves. Best I ran was 12.2 at 109.44 mph. EGT's were below 1150 at the stripe.

Towed some pretty big loads up very large grades. 27000GCVW up 7% 9000'ASL, Attitude said 65% throttle, cruise control on, 65 mph, 50 psig boost, EGT's were 1000F.

Ya can't beat those numbers with a single charger.

ok, besides going with MPI, what other turbo would go good with your stocker?

Joe

ok, besides going with MPI, what other turbo would go good with your stocker?

Joe


GT45

Gt47, ;-)

Yup.
The MPI Kit for the LB7 Rocks.

11.9 capable on a stock CP3 with no lift pump, just tuning & Sleeves. Best I ran was 12.2 at 109.44 mph. EGT's were below 1150 at the stripe.

Towed some pretty big loads up very large grades. 27000GCVW up 7% 9000'ASL, Attitude said 65% throttle, cruise control on, 65 mph, 50 psig boost, EGT's were 1000F.

Ya can't beat those numbers with a single charger.

sweet thats sounds good, but r runing 50 psi of boost on stock studs. cause i thought they were good to 45.

sweet thats sounds good, but r runing 50 psi of boost on stock studs. cause i thought they were good to 45.

Ran 68 for a while :)

But I believe 60 is the safe area with Twins.

Big Single 50 PSIG.

So what is comparible to a GT45 of GT47 in a Holset chargers?

Gt47, ;-)
GT45 on the LB7 turbo.. 47 is getting too big for the lb7/lly turbos


lbz/lmm it will work;)

twining a stock lb7 turbo...you are looking at a 2.8-3" turbo 70-80mm intake or min GT42/lb7 combo

So what is comparible to a GT45 of GT47 in a Holset chargers?
GT4508 runs a 80/108 comp with a 87m turbine

GT4708 80/108 92.7 turbine
GT4718 88/117.6 92.7 turbine

HX82-83 in hte holset size... and they are smaller than the GT4708 turbo

GT4508 runs a 80/108 comp with a 87m turbine



HX82-83 in hte holset size... and they are smaller than the GT4708 turbo


The HX82 Hoslet is a monster in size compared to the Garrett Equivalent.

The wheel size and lbs/min might be equivalent, but the physical size of the holset's make them hard to work around.

Maddog had an HX8X series in his truck and had to notch the framerail 3" to get it to fit.:eek:

The HX82 Hoslet is a monster in size compared to the Garrett Equivalent.

The wheel size and lbs/min might be equivalent, but the physical size of the holset's make them hard to work around.

Maddog had an HX8X series in his truck and had to notch the framerail 3" to get it to fit.:eek:
maybe so.. acording to the site the HX82 is only rated at ~1200hp and proble doesnt spool as nice as the garretts....
http://www.holset.co.uk/files/2_1_1_7-Holset%20HX82-83.php
HX82 is rated @ 1.5kg/s or 90KG per minute
GT6041
http://www.turbobygarrett.com/turbobygarrett/catelog/Turbochargers/GT60/GT6041_731377_1.htm
iirc 1 KG = 2.2lb and 90KG would be 198lb which flow wise is close the the GT6041 thats rates for ~2000hp... something isnt matching here........................

so an HX 60 wouldnt do a whole lot for me with my stock LB7?

so an HX 60 wouldnt do a whole lot for me with my stock LB7?
my understanding looking at the info the HX60 is rated for 360-600hp

basicly the same as GT4088, HTT, BD A4K turbos

So whats the best way to go, other than MPI... GT45? Will it give me performance worth my time and effort?

in a twin setup with stock LB7..

so an HX 60 wouldnt do a whole lot for me with my stock LB7?

HX60 is another huge bastard. Huge housing size for the performance. I would put Nathan's Sekrut Skwirl bottom turbo against it any day for ultimate performance.

Another thing, the Holset60 is bigger physically than MPI's bottom charger.

Bigger physical size does not necessarily translate into more flow, or better boost charecteristics for our engines.

The HX60 works awesome on a 15L ISL, but it has a wee bit of a displacement advantage and is only flowing air to 650 HP.

There are better options available to us. Holset chargers are nice because they are cheaper than Garrett or Nathan's turbos, but they are HUGE, hard to package, and have less than friendly boost charecteristics.

IMHO

So whats the best way to go, other than MPI... GT45? Will it give me performance worth my time and effort?
...for a stock LB7 turbo. i know it can light a 4202..
4508 with a 1.01 A/R turbine would be pretty darn close to max for the stocker.
when picking turbing houings the tigher the a/r number the quick/sooner the turbo will spool

you WILL need a waste gate to controll the big turbo as well

...for a stock LB7 turbo. i know it can light a 4202..
4508 with a 1.01 A/R turbine would be pretty darn close to max for the stocker.
when picking turbing houings the tigher the a/r number the quick/sooner the turbo will spool

you WILL need a waste gate to controll the big turbo as well

Is that word supposed to be "higher"? I still dont understand what the heck you all are talking about when you post a/r, wheel sizes, etc.....wish I did understand it.

Who in the world sells the piping necessary to connect a stock LB7 turbo to a GT45 anyways? That LB7 exhaust housing has that screwy outlet. Where would you get the pedestals?

Which one of those GT45's is the best one to run with a stock LB7?

Is that word supposed to be "higher"? I still dont understand what the heck you all are talking about when you post a/r, wheel sizes, etc.....wish I did understand it.

Who in the world sells the piping necessary to connect a stock LB7 turbo to a GT45 anyways? That LB7 exhaust housing has that screwy outlet. Where would you get the pedestals?

Which one of those GT45's is the best one to run with a stock LB7?

yeah same here. suppose i were to get a gt42 twin it with the stocker. what do i need for the plumming part of it. i could do it on a dodge but not on this duramax.

Is that word supposed to be "higher"? I still dont understand what the heck you all are talking about when you post a/r, wheel sizes, etc.....wish I did understand it.

Who in the world sells the piping necessary to connect a stock LB7 turbo to a GT45 anyways? That LB7 exhaust housing has that screwy outlet. Where would you get the pedestals?

Which one of those GT45's is the best one to run with a stock LB7?
tighter or smaller housing

right now only person that has piping close to that is MPI but you have to get the kit as well.

88/108 us the compresser wheel size. first number is the inducer/intrance of the wheel. second is hte exducer of the outer edge of the wheel.

A/R is area to radius. bassic meaning is the smaller the number the faster the air moves or greater velosity. thus allowing the turbo to spool sooner.

here is some reading material in three steps... of basic turb termanologey
and theroy
http://www.turbobygarrett.com/turbobygarrett/tech_center/tech_center.html

Thanks Bu. Reading that makes me think back to calculus and the tough time I had with it. :lol:

Thanks Bu. Reading that makes me think back to calculus and the tough time I had with it. :lol:
that was calculus?? didnt know that... found it pretty easy on the formulas

officialy i have never taken anything high the pre-algebra:eek:

hell if I know what it was...it just brought my old Calc nightmares back....

hell if I know what it was...it just brought my old Calc nightmares back....
your welcome):h

I plan on tackling the piping myself. Cutting up an old downpipe to get the flange that bolts to the turbo, and going from there fitting everything to the passenger side. Pretty much mounting everything in the same locations as the MPI. Guranteed, it probably wolnt look as damn good as the MPI, but its not going to run me $4000 plus either. Thats IF i decide to do it. Just trying to get my ducks in a row right now. It would probably be next winters project if i decide to do it. I've thought about it before, but seeing as how the thread was already started, i figured i would get some questions answerd. Thank you very much Malibu and Juice for all your info.

Joe

Another question i had, Would you still run the factory wastegate on the stock turbo? I know i'm going to have to wastegate the big boy, but i was just wondering about the stock charger. Would the 30-32 psi i'm seeing right now be enough to feed the big charger. I know any more than that, your getting the stock charger out of its " safe zone". How will that workout?

Joe

I plan on tackling the piping myself. Cutting up an old downpipe to get the flange that bolts to the turbo, and going from there fitting everything to the passenger side. Pretty much mounting everything in the same locations as the MPI. Guranteed, it probably wolnt look as damn good as the MPI, but its not going to run me $4000 plus either. Thats IF i decide to do it. Just trying to get my ducks in a row right now. It would probably be next winters project if i decide to do it. I've thought about it before, but seeing as how the thread was already started, i figured i would get some questions answerd. Thank you very much Malibu and Juice for all your info.

Joe


Thanks for the kind words Joe, But most of my information on Twins has come from Nathan himself.:)
He's always been there for me, which is why i never feel bad spending money with him. :)

I would deffinitly LOVE to have a set of his twins, but i just cant swing the $4000+ right now. His kits are deffinitly top of the line. Very nice.

Joe

i plan on doing it myself to (well my some of my cummins buddys will help to). but i want to see if i have this right the bottom turbo (as u guys call it), is where the stocker is now correct? so if i left the stocker in place through the intercooler into a GT42, then to the engine. Now the exhaust would go through the stocker to the GT42 with an external wastegate, then out the A**. Now how is the cold air intake ran, i know to the stock one but how? just doesnt seem like there is enough room. thanks for any info

I would deffinitly LOVE to have a set of his twins, but i just cant swing the $4000+ right now. His kits are deffinitly top of the line. Very nice.

Joe


I would send him a PM for some guidance. Seriously, he is the one with the first hand knowledge. He set mine up, and then we tweaked it to perfection. Actually, he did most of the tweaking and explaining. I have a pretty good idea where it should be at, but I do not want to 'guess' and cost you a charger or two from overspeed.

Better to get that from Nathan directly.

I would deffinitly LOVE to have a set of his twins, but i just cant swing the $4000+ right now. His kits are deffinitly top of the line. Very nice.

Joe

Use VISA:D

they sponsor a lot of motorsports, now use them for your own brand of fun! :ro)

i plan on doing it myself to (well my some of my cummins buddys will help to). but i want to see if i have this right the bottom turbo (as u guys call it), is where the stocker is now correct? so if i left the stocker in place through the intercooler into a GT42, then to the engine. Now the exhaust would go through the stocker to the GT42 with an external wastegate, then out the A**. Now how is the cold air intake ran, i know to the stock one but how? just doesnt seem like there is enough room. thanks for any info

Here is the pathway: Intake filter into the GT42, into the Stock IHI charger through the intercooler into the engine. Exhaust from the manifolds into the stock IHI then into the GT42 ond on out the tail end.

LOL.. i try to stay away from using VISA for " the hell of it " kind of purchases!

LOL.. i try to stay away from using VISA for " the hell of it " kind of purchases!

He He.... MASTERCARD works great too.

For all those 'Priceless' Corvette Kills.

Forget Rustangs... once you move up to Twins, you get to 'Kill' the guys who think they are the top of the foodchain :ro)

what kind of power would MPI twins make using the LB7 IHI with good tuning? Head studs are needed correct? And I'm assuming that rods sould be safe periodicaly.

what kind of power would MPI twins make using the LB7 IHI with good tuning? Head studs are needed correct? And I'm assuming that rods sould be safe periodicaly.

I had no problem making ''''550''' with them. Mind you, a 12.2 at 109mph indicates higher than the dyno number would suggest.

I was running the Edge Juice, PPE ET Hot Twinflash, 4" Banks Exhaust, AFE airfilter (included in the twins setup) and that's it.:)

No drugs, no drama, just pure unadulterated #2 POWER :ro)

Guys with lift pumps were seeing 35-60HP more than I was (and they were running better tuning via EFI Live)

Head studs are not needed with the Twins so long as you keep things 60 PSIG and below.

Nice cool charge from twins exerts less cylinder pressure than a large single will at the same pressure with greater oxygen density.

Rods on anything become suspect over 480-500 RWHP IMHO

what kind of power would MPI twins make using the LB7 IHI with good tuning? Head studs are needed correct? And I'm assuming that rods sould be safe periodicaly.
iirs bobo truck is stock ihi and big turbo wiht a built engine under it

http://youtube.com/watch?v=bLOtnMSOCMI

I think Bob's truck is the full-on MPI twins setup. Dont think the stocker was used.

I do kinda like the idea of a GT45/stocker combo, though.

Nice cool charge from twins exerts less cylinder pressure than a large single will at the same pressure with greater oxygen density.




Hey Juice, I don't mean to call you out, but I was curious if you have any info you can offer to support the lowering of peak (I assume you mean peak) cylinder pressure idea?

It seems like what you're getting at is that the twins are nicer to the pistons. I agree with that, but it seems like it's the lowering of EGT's, not neccessarily peak cylinder pressure that is to thank.

If I'm off base here, it wouldn't be the first time :) ,

Nick

Hey Juice, I don't mean to call you out, but I was curious if you have any info you can offer to support the lowering of peak (I assume you mean peak) cylinder pressure idea?

It seems like what you're getting at is that the twins are nicer to the pistons. I agree with that, but it seems like it's the lowering of EGT's, not neccessarily peak cylinder pressure that is to thank.

If I'm off base here, it wouldn't be the first time :) ,

Nick

Nick, I'm basing that on the adiabatic efficiency of the charger itself. How much is a single superheating the air in it's map and beyond in the cases of the 3.5:1+ PR ratios of a 50PSIG Aurora K31, and the drive pressures excerted on the small exhaust housing to get the compressor section into it's sweet spot.

In Twins, typically you are heating the air less prior to the CAC than a single as both chargers are working well within their peak efficiency maps.

For every 100F drop in intake temps roughly equates to 5-7% increase in HP on a turbo diesel. Much of that is due to more oxygen.
Also, since we are dealing with a CI engine, the cooler the temps in the combustion chamber, the less chance of preignition on the compression stroke, and therefore safer to run slightly higher boost ranges without suffering from headgasket loss.

I don't know a single Twinned truck running 55PSIG-68PSIG or more that has blown a headgasket.

In the Case of a GT47 or an Aurora, run them past 55 on stock fasteners.... and there are headgasket issues.

Thanks Juice,

Pretty much boils down to a detonation issue is what it sounds like.

I know you've credited the higher temp intake charge on the single, it seems like the exhaust valve and piston could also play a big role in contributing to the detonation considering their surface temps' correlation to EGTs.

... good info, it's going to be interesting to compare this idea to the chamber pressure monitor data and see at what exhaust gas temp the detonation starts to cause big trouble.

Thanks again,

Nick

Thanks Juice.

Thanks Juice.


x2

I plan on tackling the piping myself. Cutting up an old downpipe to get the flange that bolts to the turbo, and going from there fitting everything to the passenger side. Pretty much mounting everything in the same locations as the MPI. Guranteed, it probably wolnt look as damn good as the MPI, but its not going to run me $4000 plus either. Thats IF i decide to do it. Just trying to get my ducks in a row right now. It would probably be next winters project if i decide to do it. I've thought about it before, but seeing as how the thread was already started, i figured i would get some questions answerd. Thank you very much Malibu and Juice for all your info.

Joe


Nathan spent considerable time figuring out what works best. I watched him do the install and there's a quite a bit involved. His kits have a lot of fabricated pieces and far more goes them than people would imagine. Just making those pipes from sections and bends requires more than a little skill. One of them takes 5 hrs on a jig and lots of tricky welding to get it right. And that piece has to fit perfectly. After doing one of these twin setups and going through everything involved to get it right including screwups and mistakes, that $4000+ price will look very reasonable.

Nathan spent considerable time figuring out what works best. I watched him do the install and there's a quite a bit involved. His kits have a lot of fabricated pieces and far more goes them than people would imagine. Just making those pipes from sections and bends requires more than a little skill. One of them takes 5 hrs on a jig and lots of tricky welding to get it right. And that piece has to fit perfectly. After doing one of these twin setups and going through everything involved to get it right including screwups and mistakes, that $4000+ price will look very reasonable.

I agree 100%.

It's worth every penny, and then some. MPI's kit is actually going to work out better than a home built one... and your rig is down less time.

When you factor that it, it is kinda silly to try the DIY route.

I agree 100%.

It's worth every penny, and then some. MPI's kit is actually going to work out better than a home built one... and your rig is down less time.

When you factor that it, it is kinda silly to try the DIY route.
thats kinda a slap in this guys face john.....................

http://www.dieselplace.com/forum/showthread.php?t=188894&highlight=4718

if the guy has the know how and will too let him do it.. this DIYer project aint a week end project... if he want to spend the time to make it more power to him:D I LOVE the DIYer:D

for most people MPI is the way to go...... but for the rest of the guys it I wanna do it myself!

and it sounds like these guy are doing the alot of foot work to get 2+2 to equal 4 ;)

thats kinda a slap in this guys face john.....................

http://www.dieselplace.com/forum/showthread.php?t=188894&highlight=4718

if the guy has the know how and will too let him do it.. this DIYer project aint a week end project... if he want to spend the time to make it more power to him:D I LOVE the DIYer:D

for most people MPI is the way to go...... but for the rest of the guys it I wanna do it myself!

and it sounds like these guy are doing the alot of foot work to get 2+2 to equal 4 ;)


OK, well it's not to be taken as a slap. :) Just one of those things. If you have the time and a second vehicle and the will to do it, go for it! The results can be phenomenal. My own needs from my personal truck are different, and downtime is not much of an option, so spending the green makes more sence to me.... especially if y'all saw me attempt to weld:D

just want to make sure:)

I agree 100%.

It's worth every penny, and then some. MPI's kit is actually going to work out better than a home built one... and your rig is down less time.

When you factor that it, it is kinda silly to try the DIY route.

Were can you buy parts for these MPI kits?? Looking for a wastegate for stock turbo.

Were can you buy parts for these MPI kits?? Looking for a wastegate for stock turbo.
various parts stores....

here is one of them http://www.atpturbo.com/

Were can you buy parts for these MPI kits?? Looking for a wastegate for stock turbo.


If I can locate my old wastegate do you want it?
And if I do.....


Pay for shipping and a 5.00 donation to the ALS foundation garantees it to you.:)

Yes I would like the wastegate!!!

Here's somethin to think about
70mm Cheetah + Turbo Brake + Aurora= BIG POWER!
Or you guys can come up with somethin along those lines, I'm not up on all my turbo's but I know with the control of the VVT would help to make boost quick and also have enough to light a good size secondary turbo

Here's somethin to think about
70mm Cheetah + Turbo Brake + Aurora= BIG POWER!
Or you guys can come up with somethin along those lines, I'm not up on all my turbo's but I know with the control of the VVT would help to make boost quick and also have enough to light a good size secondary turbo
A5K is IMO too small for the large charger now a A6 or A7 could be a diff store when the get the specs out:cool:

Think bigger :D twin love begins @ 76mm and up :D

Think bigger :D twin love begins @ 76mm and up :D
i ats had spec on said 6000 and 7000 turbo i might have said differently

a5k is 71.41mm
4202 is 74.70mm
cheatah 70mm
yeah you could twin with a withg all three.. limit would be about 700-800hp