MPI Twin Owners, Come in!

[ZR1160]

I have one of the 10 first sets built for the LLY (LLY twins came before the Lb7 twins). So mine are the Gen I non-wastegated version, BOBO did my tuning, I also had 29% sticks, and headstuds, I drove and towed with a "hot street"tune for over 80K miles. This past fall, I think I blew and head gasket and hurt a piston, motor hasn't been apart yet...getting my spare built with Carrillo rods, 16:1 LLY pistons and studs.

My twins maxed out at 45psi I am adding a 68mm Cheetah and LBZ CP3 with a modded regulator to the new motor, the Cheetah should keep the quick spool but allow more boost with out a waste gate and less backpressure...

The non-wastegated LB7 twin made 60psi with the wastegated LB7 stock turbo...IIRC

 

[duratothemax]

this is something that hasn't been tested yet as far as I know, but I cant imagine it being worthless , maybe expensive would be a better word for it. I plan on trying this setup someday, i'll post up the results

LBZ492 tested it and says it wasnt worth it when he compared it to Bobo's stock LBZ charger/twins

ben

 

[TrentNell]

Agh, bummer. Hmmm. Phone call is needed tomorrow I guess.

i am sure nathan could adapt one of his big twin kits he is building for the lb7's to fit. the small charger in that kit is based around the s300 so most of the piping would have all of the correct flanges to work with the htt, and the kit with the base charger it will support 800-900 hp and with a upgrade to the big charger it will support more. i talked to him last week and he should be driving around that kit this week to see if if anything rubs , so the r&d is all finished .

 

[IdahoRob]

There are a few MPI twin trucks out there running a Cheetah and one running the new garrett VVT(still ironing this one out) that I'm tuning.

I feel either run the stock top charger, proven good for 800HP on a built engine, or go with Nathan's big set which should be in the 800-1000HP range with supporting mods.

 

[SmokeShow]

forget going with the cheetah-type chargers??? it's either use the stock charger in the twins or go balls beep?!?!

 

[ZR1160]

There are a few MPI twin trucks out there running a Cheetah and one running the new garrett VVT(still ironing this one out) that I'm tuning.

I feel either run the stock top charger, proven good for 800HP on a built engine, or go with Nathan's big set which should be in the 800-1000HP range with supporting mods.

I'm hoping on the non-wastegated twins that the cheetah will help, or maybe should get the newer wastegated one????

 

[juddski88]

i agree with ben, and for what you pay for a cheetah you really don't get the customization you'd get with a cheaper S-series or Holsett or any other custom chargers that are built for twinning together. IMHO the cheaper you can buy chargers, the better. as for the supporting mods, if I was going to build a motor, I'd build it as cost effectively as possible and do a lot more customizing of the air supply plumbing and fuel supply plumbing because those I think are the little restrictions that many don't budget.

 

[racinmike77]

The standard kit comes with a 42R correct. Would it be possible to order the kit without the turbo or with a journal bearing GT42 or does nathan have any plans on a kit with a S400. Id like to try twins but cant see shelling out $5000.

 

[ChevyDieselLLY]

yea i talked to Mike L the other night and if the twins are good enough for him i think they will be more then good enough for me. i will most likely go with the BIG kit just to have it. no reason to buy 2 kits when you can just do it right the first time

 

[SIKDMAX]

Anyone know if I can do the MPI kit with the HTT Promax McRat Turbo as the stock location turbo?

 

[TrentNell]

Anyone know if I can do the MPI kit with the HTT Promax McRat Turbo as the stock location turbo?

see post #23 and talk to nathan on any other details .

 

[Righteyeblind]

The standard kit comes with a 42R correct. Would it be possible to order the kit without the turbo or with a journal bearing GT42 or does nathan have any plans on a kit with a S400. Id like to try twins but cant see shelling out $5000.

No they come with a borg warner turbo I think. Definitly not a Garrett

 

[malibu795]

Anyone know if I can do the MPI kit with the HTT Promax McRat Turbo as the stock location turbo?

a 66mm turbo will easily light a 80-95mm turbo thats 4718/5533 size
looking are over 1300hp worth of air...

if 900 is your goal get a s475/4708 equivalant charger and be done with it.

 

[TrentNell]

a 66mm turbo will easily light a 80-95mm turbo thats 4718/5533 size
looking are over 1300hp worth of air...

if 900 is your goal get a s475/4708 equivalant charger and be done with it.

if you will never tow and dont drive your truck everyday i would have to say he's right a large single will net the hp and is alot cheaper, but if your in a spot like i am and have to tow /race/haul the family around and still want enough air for 800-1000 hp then twins are the only way to go , i guess the real question is want you want out of driveability and want you'll pay to get it.

 

[SIKDMAX]

Moneys not as much of an issue - I want twins and I tow and want it to be daily drivable.... its not going to be a DAILY driver but I will drive it several times a week, and not hesitate to jump in it and tow 7-10k pounds 4 hours.

Looks like the HTT in stock location with a ___________ (not sure what turbos the regular or big MPI kit comes with for the big boy) would work well then.

 

[05_LLY]

I have one of the 10 first sets built for the LLY (LLY twins came before the Lb7 twins). So mine are the Gen I non-wastegated version, BOBO did my tuning, I also had 29% sticks, and headstuds, I drove and towed with a "hot street"tune for over 80K miles. This past fall, I think I blew and head gasket and hurt a piston, motor hasn't been apart yet...getting my spare built with Carrillo rods, 16:1 LLY pistons and studs.

My twins maxed out at 45psi I am adding a 68mm Cheetah and LBZ CP3 with a modded regulator to the new motor, the Cheetah should keep the quick spool but allow more boost with out a waste gate and less backpressure...

The non-wastegated LB7 twin made 60psi with the wastegated LB7 stock turbo...IIRC

Just wandering why youd want to put a 68mm inducer turbo over another 68mm inducer turbo?, You wont be able to get any more air out of the big one than you all ready are? More psi can be had out of the current setup with tuning not sure if its worth it or not though as egts seem to start coming up the harder you push the boost?

 

[SIKDMAX]

Would I be right in assuming the big charger in the MPI kit with a HTT would be a S400 or S480?

 

[durallymax]

Om the big kit the HTT or BD Supermax is used in the stock location. At least thats what nathan said when I talked to him a couple months back.

The Big turbo in that kit is well BIG. I know it wont fit into a 3.0 twin class like my organization, however I still plan to run them as I can run a bushing.

The small twins can be run on a stock motor. Just dont add twin CP3s.

They may seem pricey but its hard to build a kit yourself much cheaper. And nathans are bolt on and already have the R&D so why not just buy what he hastested.

I may try something different though as I like to be different, but most likely will end up with the big kit.

 

[malibu795]

if you will never tow and dont drive your truck everyday i would have to say he's right a large single will net the hp and is alot cheaper, but if your in a spot like i am and have to tow /race/haul the family around and still want enough air for 800-1000 hp then twins are the only way to go , i guess the real question is want you want out of driveability and want you'll pay to get it.

that was ment as twin setup

a 66mm turbo is fairly towable pending how it is setup

 

[SIKDMAX]

Durally thats what I plan on doing... just going to pick up Pats HTT he has for sale more than likely and put on in stock location and run as a single for a few months while my checking acct recovers from the built motor, then add dual cp3 and nathans twin kit using the HTT as the small guy in stock location.