t3/t4 turbo sizing on a 3400

[Froggx]

Does anybody have knowledge of what size t3/t4 hybrid is the best fit for a 3400. T3's all seem to be too small to support these engines, and going to a t04 requires an external wastegate which adds a good amount of cost and piping complexity so the hybrid seems to be my best choice. I was thinking one with a 57 trim t04e compressor wheel and an A/R of .63 on the turbine side would be about optimal. For my application I'm looking to run about 7 psi non intercooled or 10 psi intercooled and I'm aiming for between 250-300 hp at the wheels. I'd like full boost to be able to be held until 6000 rpm and I'd like it to be generating boost by 2500 rpm. Would that turbocharger meet these requirements or would I have to change the compressor or exhaust size. Would an exhaust A/R of .82 be a better fit?

[dbtk2]

A proper sized T3 actually wouldn't be too bad for a mild setup like yours. My TGP has a T25 (T2 based) and it spools instantly (well under 2k...I can break torque and hold 10psi) and is supposed to be good for about 280hp. So using a T3 would give you quick spools and you would be able to make the amount of power you want. That would be about all the turbo would be good for, but if you want fast spooling then you want a turbo that is almost too small for your setup.

Shawn

[Froggx]

Fast spooling isn't necesarily as important as being able to hold full boost to redline in this case. Looking at compressor maps, I didn't see anything t3 that could hold the 3400 to 6000 rpm. 3400 would need more cfm's than the 3.1 due to the larger displacement and better flowing heads as well, right? From my understanding the tgp's had almost too small turbos and injectors stock. By any chance do you know where a compressor map for the stock tgp turbo could be found?

Here is where I charted a 3400 on a 57 trim t04e compressor at 7 and 10 psi at 4000 and 6000 rpm assuming 80% volumetric efficiency.

[Froggx]

Also, here is a map of a super 60 t3 on the same scale.



It looks like it would have much better low end response as you said, but I don't see boost holding nicely up to 6000 rpm.

[dbtk2]

Fast spooling isn't necesarily as important as being able to hold full boost to redline in this case. Looking at compressor maps, I didn't see anything t3 that could hold the 3400 to 6000 rpm. 3400 would need more cfm's than the 3.1 due to the larger displacement and better flowing heads as well, right? From my understanding the tgp's had almost too small turbos and injectors stock. By any chance do you know where a compressor map for the stock tgp turbo could be found?

I have no idea where you can find a compressor map for the stock TGP turbo. The TGP turbos and injectors were sized great IMO for what the car was meant for stock. GM only wanted them to put out 205hp, and the turbo is supposed to be good for 280, and the injectors about 250hp...so GM gave themselves a window there. GM also sized the turbo to "virtually eliminate turbo lag." With a chip the injectors are basically at their limits and the turbo is close, but thats basically all most TGP owners ever do, so the small turbo is fine because it spools very quick and holds full boost to redline. On my STE I can hold full boost (10psi) all the way to my 6200rpm limiter, and on my dads TGP it holds full boost (11psi) at least until it shifts at 5800. (haven't held that to the limiter so I'm not sure, but I think it would) So basically, in my current setup, the turbo is about the exact size I feel I need. It spools quick and holds full boost until redline. Now after I finish the engine, I'm sure I will need a bigger turbo, but I plan on that by the end of this year/beginning of next. Obviously the difference in the size of the engine will make a difference in turbo size, but the point I'm trying to make is that the very small T2 based turbo on my car can put out AT LEAST 250hp, spool instantly, and hold full boost to redline, so why wouldn't a decent sized T3 put out over 300 on yours, spool quickly, and hold full boost until redline?

I will admit that I am not the most knowledgable person when it comes to turbo's, but I really can't see any reason why you would need more than a big T3 for your setup.

Shawn

[Froggx]

I admit I don't know much about turbo sizing either, your input is greatly helpful though as it makes me think I might be aiming too large for my setup now.

[FieroGT87]

Interesting read, I'm learning as well. I have a IHI RHB6 turbo that max's out at 592 CFM just over 300 HP and 290 Torque. But I don't understand the charts to well, or sizing and limitations. Like Froggx stated any input is helpful.

Thanks,

[Froggx]

If you have a compressor map, post it up and I might be able to help you, I'm a lot better at analyzing them than I was a year ago.

[timg]

57 and 60 trim aren't that different. I would suggest plotting a 60 trim compressor map- they're very efficient and will give you a bit better high end. For the turbine, a 0.63 a/r is way too small for a 3400. Consider a .82 a/r turbine housing. This turbo should spool quite quickly while still giving you a good top end.

Tim

[imported_germ]

i am using a 57 trim, .50 AR compressor side (cold), .84 AR exhaust side (hot)


it starts spooling at around 1800 rpm's at WOT and at 5psi i am full boost by 2700 rpm, and at 10 psi im hitting that at around 3200 rpms, and 12+ psi is just around 3500.

the launch and engine management will play a role (slightly) in when you spool up (i.e. timing levels and fuel maps)

and in all honesty, i feel that the turbo i choose is slightly to big. i will be ordering a 57 trim, .50 ar cold, and .70 ar hot in the near future.



on a side note, use an external wastegate. you will most like NOT find a larger turbo for the 3400 with an internal wastegate.

[imported_germ]

FYI, what works for the 3.1 turbo setup will most likely not be very efficiant with the 3400.

the T25 is almost to small for the 3.1, let alone the 3400.


the ONLY T3 turbo i would even think about using is a Super T60 or Super T70.

but even then, they will be slightly to small, but they would be a LOT of fun to drive

[FieroGT87]

Heres the web page on the IHI turbo with the map and other info.

http://www.ihi-turbo.com/turbo_RHE-RHF.htm

The RHB6 is the same as the RHF6.

I have not been able to find any info on trim or the AR.

Any thoughts?

Thanks

[mr_merkur]

I know I'm new, but I have a big collection of compressor maps if someone wants to host it hit me up and I'll send them to you for the hosting. As for our setup were gonna run a hybrid turbo for now, and if we wanna go bigger I'll just make a new crossover, cause I got skillz :P haha.

[gboogie99]

now thats funny. I have a 3100 and i charted the turbo for my engine as a t25 w/ a/r .83 to put out 290hp at 10psi. Only thing is it wasnt a "t25" but a "gt25" that actually offers more cfm. That means the boost stays low and I get theoretically should get over 125 hp over stock...anybody wanna to check on turbosizing should try doing a search for turbo calculator. Its what i used and is actually in a post on the site somewhere...

[Guest]

now thats funny. I have a 3100 and i charted the turbo for my engine as a t25 w/ a/r .83 to put out 290hp at 10psi. Only thing is it wasnt a "t25" but a "gt25" that actually offers more cfm. That means the boost stays low and I get theoretically should get over 125 hp over stock...anybody wanna to check on turbosizing should try doing a search for turbo calculator. Its what i used and is actually in a post on the site somewhere...

There is a HUGE difference between a T25 and GT25, I wish more people would realize this.

The GT series, while undersized for thier total HP supporting capabilities, are much different design than a conventional turbo, that would go by family designations like T25, T3, T04, etc, which BTW are all Garret family names, but people will still try and adapt the same family names to other companies. :-?