Alright, I have posted several questions about twin turbos to help me try to decide what I want to do. I think I have decided. The short block is pretty well set, there were no questions on that. It is a 355 with 7.75:1 CR, fully forged bottom end, file fit rings, etc. Cam Motion is who will grind my cam. I will be running vortec heads and either Accel DFI or blow thru carb, that is not decided yet. MSD 6BTM will be in charge of the ignition. I am going to make my own headers. My only question now is, will the turbos I have in mind be worth any kind of power. I am planning on running two TD05h turbos off of first gen DSMs such as eclipse, talon, and laser. I can not find the AR's on these nor the compressor maps. I have read "turbochargers" by Hughes Macinnes. It tought me alot, except I still do not know how to read a map, so if I found them, I still would not know. Any help would be greatly appreciated. Thanks

 

i could be way off but it seems like those turbo's would not be "big" enough. they're ment to be on a 2.0L and half of your motor is almost 3.0L. but like I said I could be way off Im new to turbos

 

That is what I was afraid of. I you do the easy math they seem to small. I have been loking into a couple Garret T3's. All I know is I want turbos with internal wastegtes and ones that can produse some nice numbers.

 

Yeah, TD05H turbos will be too small for your setup. With that low compression and forged internals, you're probably looking at running some high boost? Look into some T3/T4 hybrid turbos with ~.63AR turbines. 89JYturbo upgraded from twin T3's to the hybrids b/c of exhaust restriction in the upper rpm's.

 

I plan on pushing serious boost at the track. I would like the motor to see 20-22 lbs. of boost. I t will not see more the 10 on the street though. I ahve thought about the hybrids. Thanks

 

With the setup you described I’d be looking at something like a pair of even the bigger T04’s, some of the medium sized GT series or so… roughly 2-3x the size of those things you’re looking at. Of course, with parts like that you're also looking at a really serious bottom end... otherwise I don't see the point of running compression as low as 7.5:1

 

The bottom end is pretty stout. JE forged pistons, Eagle 5140 H-Beam rods with cap screws, Eagle forged crank, and moly file fit rings. I have thought of filling the block 1/4 of the way, but I may drive this on the street some so I am not sure yet. I am also going to run a vacuum pump of some sort.

 

compressor maps are easy to read once you get the hang of it... with the numbers i punched out for my motor, boost level, and RPM ranges

im looking @ a TT T-61 set up... which you max boost 10psi @ peak efficiency around 5500rpm and still have almost full efficiency at 3500Rpm for midrange power

 

just get the banks kit for 6000.00 complete. cant go wrong 61-1 turbos and log manifolds which last forever. and designed for third gens.

 

I have thought about buying a kit but where is the fun in that. I want to build my own. Anyone can but a kit and slap it on. I like the fabrication and research that goes into a project. I am not in a hurry to get it done, if I was I would buy a kit. I need to learn to read compressor maps thoug so I wont have to ask so many questions.

 

for reference i just got done selecting turbo maps... im going to run two precision T04e60 turbos....

 

im building a small turbo motor. with a t88, with custom wheel. should be about 1400 hp small block.

 

does any one have the sight for the banks kit????

 

To use the banks kit, is there any modding I'd need to do to my stock 350?

 

If You get a kit with manifolds, and a pair of turbos, there is still plenty of fabbing to do. I got the Innovative manifolds with a pair of t04s 60-1s...better than the Banks stuff, imo...but the s cover will not fit the stock hood...get at least 8.5:1 CR...

 

Banks Twin-Turbo | Banks Power: Twin-Turbo Engine Packages

 

Ok, I have decided to go with garrett t3s. I have one and I am getting ready to get the second. I am going to rebuild them myself and have a guy that builds turbos for cummins balance the shaft. What I want to know is can I buy a compressor housing and wheel for a t4 and buildmy own t3/t4 hybrid. The turbo I have is off of a turbo coupe. It has A/R .63 on it. I have nbeen told this will work great.If anyone knows if this work please let me know.

 

In my opinion you should be doing more research before buying anything. When I researched what I wanted to do I first defined my goal, what I wanted the end result to be. Then I focused on the motor, came up with what I thought was a good motor combo to support my goal. Once you've got the motor spec'd out you need to determine flow in CFM, RPM ranges, etc, etc. Then once you know all that, then you go find the turbo(s) that you think match up well by reading the compressor maps. At this point its possible you'll want to re-arrange parts of the combo to better suit your goal. Keep in contact with whoever will be making the cam, run it by them. Also keep fueling in mind, and how you plan to manage the tuning of the system.

So before buying stuff I think it might be worthwhile for you to make sure what you're considering will accomplish what you've set as your goal, and equally important its a good match for your specific motor. Because you don't want to go through all the trouble of building the system, and then possibly be let down if it does not perform to your expectations. Good luck!

 

I have been researching this for a year. I have the short block of the motor done. I have not had the cam ground yet just in case I change my setup. From all of my research I have determined that these will be the best turbos, but I wanted to know if i could put the t4 housing and wheel on it. This would allow me to lower boost and maintain the volume of air which will be safer on the motor and turbos.

 

I will give you a little info about my setup with twin 60 trim, .63 A/R turbine turbos (just like you have and may install).

Engine is a 355ci with ported 993 GM heads, LT1 intake, 216* @ .050", .454" lift both intake & exhaust, 8.6:1 CR, 7PSI of boost, converted stock TPI exhaust manifolds, rev to 6K RPM.

Theoretically, the turbos are at the right side 65% efficiency line of a turbo map. Using actual ALDL data, they are at about 68%-65% line. In general, they are on the small side. If I increase the boost they will stay right on the 65% or get worse. Increasing the boost will spin them faster and work them harder. I can't complain about the lag though because there isn't much, but I think that is more a function of the torque converter stall RPM.

Your engine is capable of much much more HP than mine and will flow a lot more air. I hope that helps you in choosing turbos for your setup.

 

So, are you saying they are to small on the turbine side or the compressor side. I think if i put the t4 housing and wheel on there that should bringthe efficiency up a little right.

 

im planning two innovative streetfire T4s... which is what i have listed above.... they are almost perfect for a "well" breathing bored 350.