T4 turbo questions.

[turbhoe]

i've been searching and reading and reading and reading. now i want to ask some questions. when i do my dmax swap i want to do twins. i have a tc78 by turbnetics. its a 78mm compressor and a 68mm exhaust inside a .96A/R t4 housing. if i gated it could i use this as my low press turbo? i want to use the stock one for the small turbo. i want to have at least as much hp (650ish whp) as i do now when i do the swap. thats of course on the big tune. i won't drive around using that much all the time.

i'm also trying to weed through all this and figure out if i need dual cp3's for this amoiunt or if i can get away with just bigger injectors and maybe a moded cp3. i don't plan on going over 700.

i'm still searching and reading.......:thumb:

 

[TrentNell]

i've been searching and reading and reading and reading. now i want to ask some questions. when i do my dmax swap i want to do twins. i have a tc78 by turbnetics. its a 78mm compressor and a 68mm exhaust inside a .96A/R t4 housing. if i gated it could i use this as my low press turbo? i want to use the stock one for the small turbo. i want to have at least as much hp (650ish whp) as i do now when i do the swap. thats of course on the big tune. i won't drive around using that much all the time.

i'm also trying to weed through all this and figure out if i need dual cp3's for this amoiunt or if i can get away with just bigger injectors and maybe a moded cp3. i don't plan on going over 700.

i'm still searching and reading.......:thumb:

I would not use it , the turbine wheel is too small as well as the housing and A/R , a gate may make it usable but thats alot of effort to build a setup based around a poor choice of turbo , not to mention a S475 is almost as cheap as the waste gate setup to make that combo work .

 

[turbhoe]

can you get away with no wastegate at all using the s475? or would a person need one before the stock turbo? LBZ is what i want to use on the sap.

 

[TrentNell]

can you get away with no wastegate at all using the s475? or would a person need one before the stock turbo? LBZ is what i want to use on the sap.

No waste gate is needed when using a T-6 S475 , and no need to gate the stock turbo .

 

[turbhoe]

ok that sounds good. the less parts the better. i would assume i could get buuy with a good single cp3 for my power needs. but what injectors to keep from having to use extreme pulse widths and timing?

 

[Bonestock]

How is your engine stock or built? Fueling it up on stock rods and pistons will most likely give up the goat if you pound on the truck awhile.

 

[turbhoe]

I'm planin on building the engine. But I'm still trying to figure out about pistons. Rods seem to be pretty cut and dry as far as what to get. But pistons are a whole other deal. If it was a gasser I'd throw some forged wiseco pistons in it and call it a day. But it seems forged in the diesel don't have a long life span. And I want to be able to drive it awhile with out worn about ring lands and all. It's not like I'll be running a 650hp tune all the time. I will have a economy tune for DD purposes. But I want the big tune for track days or for that stop light show down. Lol I was looking at cut and coated lly pistons but those seem to be up in the air if they are really the way to go or not also. Why can't they just make some steel pistons and get it over with. :angel:

 

[blk smoke lb7]

Im planning on being in the 650 700 h.p. range and i was told by alot of people just to stay with the lb7s cut and coat them so thats what i did,but i did go with the Corillos.

 

[turbhoe]

Yeah that seems to be the way to go. But you have the nah Sayers on here too. Maybe by the time I get ready something new will be out. My goal is to build after deployment. We shall see. It depends on where I go.

 

[Dirtymaxx03]

for your hp wants i'd run and s475 t6 under the stocker. as for fuel, add some 40% over nozzles and you should achieve your goal. the 40 overs will allow you to decrease your pulse width quite a bit

 

[turbhoe]

Good that's what I'm looking for is injectors that won't be uneficient but will allow pulse widths to be low. Am I correct in think around the 2000 mark is a good goal for PW at full boost? Is the "race" cover good to have on the s475? It's suppose to flow more.

Will a stock cp3 hold rail pressure or would it be a good idea to go ahead and get a good cp3. Maybe the striker cp3.

 

[Dirtymaxx03]

a modded cp3 wouldnt hurt. if you have the money the race cover is a good investment. as for pulse width....i'll let someone who is more efi savy then me answer that

 

[turbhoe]

My goal is to collect everyhing before I do the swap. That way I can build the motor and trans before it all goes in. I don't want to have to take it back out. I learned my lesson with trannies already. Point being, if I have to wait alittle longer to get a needed part then so be it. I just don't want to waste money on stuff I don't need. Like forged pistons if lb7's will do the trick.

Its not like I'm currently bored with my 12 second tahoe. I just want the diesel. If that makes since.

 

[blk smoke lb7]

What are your plans for front and rear dif?As the 1500s will be junk after the 1st 10 runs? Just wondering as i had a 99 yukon that we both loved very much.I had contimplated doing the swap but did not have the time nor space and if they came out with the diesel sub i would have 1 for sure.

 

[turbhoe]

i think i decide to go ahead and go 8 lug with dodge front hubs (bolt in) and run the 11.5 out back. i just have to put my suspension components on the 11.5. the way everything will sit in the tahoe i should be able to maintain the 52/48 weight distrubution. if this is true i won't need 4wd to launch. just some real sticky tires and it will squat like mad like it does now. i will swap to selectable 4wd (AWD now)but just for off road needs not for beating. i know the 8.6 won't handle the diesel because it doesn't handle the turbo 5.3 now. i swapped in a auto trac case that i modded to be 2wd only for awhile. i broke the left rear axle twice and my detroit locker. so i went back to the AWD.

my wife wants me to do a straight axle conversion but i'm not too sure yet cause i want to be able to get decent mileage with the swap. its hit and miss on looks for lifted tahoes.

 

[seth999]

get a race cover s475 with a t-6 1.32 a/r do 60% over injectors you can turn em down...do cut n coated lb7 pistons...they will hold up just fine...go for a bigger cp3 or 2xcp3's that will get you all the twins have to offer

 

[turbhoe]

at what point do injectors start loosing their effeciency? as in when do they stop spraying fuel and start pouring fuel (if that makes sense). if one GOOD cp3 will do the job that would be nice. would dual cp3's last longer than a single? do the built singles have a good life expectancy. can they go 100,000 miles? i will have a lift pump to feed the system, thats a no brainer.

 

[seth999]

you can turn the pulse width down...basically your getting the same fuel just faster so you can get more power and less timing...or more fuel at the same or lower timing...I've seen injectors go to 200 over at 25k+ psi they always spray

dual cp3's would last longer IMO

 

[turbhoe]

how does a person go about figuring out what size injectors are needed for their power needs? like in the gas world there is a pretty simple math equation to figure it up. i understand 60's will do the job for me. i just like to know stuff.

 

[blk smoke lb7]

i think i decide to go ahead and go 8 lug with dodge front hubs (bolt in) and run the 11.5 out back. i just have to put my suspension components on the 11.5. the way everything will sit in the tahoe i should be able to maintain the 52/48 weight distrubution. if this is true i won't need 4wd to launch. just some real sticky tires and it will squat like mad like it does now. i will swap to selectable 4wd (AWD now)but just for off road needs not for beating. i know the 8.6 won't handle the diesel because it doesn't handle the turbo 5.3 now. i swapped in a auto trac case that i modded to be 2wd only for awhile. i broke the left rear axle twice and my detroit locker. so i went back to the AWD.

my wife wants me to do a straight axle conversion but i'm not too sure yet cause i want to be able to get decent mileage with the swap. its hit and miss on looks for lifted tahoes.

For going quick and trying to keep the best mpg i like stock height or just a little lowered,i think your gonna need the 4x4 option to get good hook or the torque will just spin em if your going to twins,and i dont like the straight axel you can get the front to help out and go to an e locker if need be.Just my 2 cents,i cant wait to see the swap i will be sub'd for sure.:thumb: