k29 k31 compounds?

S

Str8jacket

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I am looking to build a work/street truck. Ve pumped. Not looking for all out but would like to get all I can while staying streetable, usual dream. Fully loaded the old girl is good for 10000lbs.
I have picked up 2 turbos coincidence has put them here as a k29 and a k31. Both bought from the other side of the country sight unseen so its a bit weird.

Ive pulled them a part and measured them up as follows


k29
turbine 82mm 69mm12 blade.
12cm t4wg housing divided.
compressor 61mm 88.5mm 7 blade.

K31
turbine 85mm 75mm*11 blade
t4 20cm divided housing
compressor 71mm 94mm*7 blade

I have done all the math on the compressor sides and off an excel calculator I found here I think, matching them together appears they should easily reach my soft goal of 500hp at the engine. And be in apretty efficient range for the comp wheels. The engine they come off are similarly matched in flow rate 60lbs min to reach 500hp, its the exhaust side I dont think will work.

Is a 12cm t4 housing too big for a secondary? And is a 20cm divided t4 too small for a primary?

I have though of externally waste gating both to keep good boost response? If not would a better housing be available?
 
Eh... its not necessarily a properly sized set of compounds but they will reach your goals.
 
DDually said:
Eh... its not necessarily a properly sized set of compounds but they will reach your goals.
Click to expand...

Thanks for the reply, would you be able to explain a bit more on what issues you can see with the sizing?

I have trouble identifying differences in sizing as 62/65/12 over 475 could be any number of combinations :doh: t3 t4 footprint? A/R? exducer? which is the majority of references I have found to what people are using.

In regards to needing big injectors, I was looking at something in the 5x13 range? Is this the size required for the HP target or due to the dimensions of the turbos used?

Cheers Ben
 
I would go a bit bigger on injector....something like 5x16s.

edit: Also, in all honesty, the k29 would probably work well just by itself, if you don't want to do twins.
 
Last edited:
JQmile said:
I would go a bit bigger on injector....something like 5x16s.

edit: Also, in all honesty, the k29 would probably work well just by itself, if you don't want to do twins.
Click to expand...

Are 5x16's going to be smokey when normally driven? And I had sort of come to the same conclusion as far as running the k29 as a single, it came off a high 400hp motor and in comparison to any maps I can find with similar size frame and wheel it is possible.

It's just that the thought of twins gets me a bit wet at the fork! :cheer:

Plus out of four turbo shops I talked to not one said compounds work or are just for tractor pulls. All of them wanted to sell me a ball bearing garrett worth more than my whole project so far, which here in Australia is 2x more than what you guys pay. It would be good to get it going as I have out laid a grand total of $200 for turbos ones good to go and one needs a reseal.

Back to turbine housings, I have compared against some 475's which are bigger compressors but similar sized turbines, but higher flow all round.

With the k31 the housing is t4 20cm the turbine diameter is 85mm would this larger than normal wheel affectively make it act like a higher a/r due to the reduced over flow the turbo can put out. Sort of like instead of small turbine large housing, the smaller wheel helps spool but the big housing reduces back pressure, the set up on the k31 is using the larger wheel in a smaller housing to still allow a reasonable level of back pressure.

It did come off a 500hp 13litre engine so one would have to assume there has been a balance reached during the design phase? I could be talking out my ass though!
 
Nothing is really smoky with tuning, other than idle. I ran 6x16s and they smoked at idle....5x25's REALLY smoke, but they're actually clean once the rpm is up....

This is at 55mph in 3rd, no smoke.

[ame="http://www.youtube.com/watch?v=j_LRovijq7E"]Rust Bucket pulling a grade - YouTube[/ame]

So, if you're willing to live with idle haze or smoke at startup, you can basically run anything.

Fuel pressure oddly seems to have something to do with it. I'm pretty confident 5x16s wouldn't smoke at idle, especially if you raised the pop pressure and lowered fuel pressure.

If you're set on twins and towing, they rock. A small single might be able to tow at 250-300hp, twins can tow at 400rwhp or more.
 
5x12 are stock for non intercooled, so much much of an upgrade
 
Imo, you'll want a smaller secondary to take advantage of the ve's low end. He341/351 over the k31 would be my choice.

Sent from my DROID RAZR HD using Tapatalk 4
 
you can grind yer factory fuel pin and adjsut the afc spring to keep low rpm/boost smoke down, but put the fuel too it when ya want it. i ran 7x.015's and now run 5x.017's and it only has a haze until you hammer down. i got my afc spring set to where the pin starts moving around 10 to 15 psi of boost.
 
chevota84 said:
Imo, you'll want a smaller secondary to take advantage of the ve's low end. He341/351 over the k31 would be my choice.
Click to expand...

This is also what my maths is telling me. Thanks. Not many he351 available in the land of oz, I can get second hand gt3582 easily second hand but nearly at the price of a new s2/300. I not sure on the open turbine housing on these t3 gt turbos. Would it be worth the extra couple hundred to buy the t4 borg warner new?

Had thought about putting the comp wheel off the k31 onto the k29 as a big single,:badidea: oh the lure of hp, not a dd then.
 
I plan on running a s360/68 as my secondary in my next setup. I have 3 s300s all have the same 68mm turbine, just different compressor housings and turbine housing.
I have one that was in a tractor fire that was a 62/68-.82AR t4 gated. And I was going to have it rebuilt to run as my secondary at one time. If you have it on hand it will probably work well. A lot of people said I couldn't run the charger I am now, and drive/make power. Well they were partially right, it is a little smoky at 1/3 throttle, but damn does it haul a$$. I've come to the conclusion that one can fudge a little in ether direction when it comes to choosing turbos. Will you make less hp than the other guy?? Who knows, every truck is different. Could your truck perform better with a different setup?? Who knows, fine tuning and end result are different to every truck owners liking, and to every truck tuners feel.

I do know ve pump trucks like t3 secondary housing a bit more than the t4s. But I'm sure it won't be all that noticeable when it's all said an done. I just forked out some $$$ for a gated housing, if it's worth it to you go for it. But building a good running truck on a budget, beats building a expensive truck that mildly performs.
 
341 works great at the horsepower you are looking for. Drill the wastegate out and do a spring gate.
 
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