Towing with boost
The truck currently has a tricked out 4.2 turbo diesel. So I love the torque from driving on boost. It runs 20psi from about 1900rpm.
My question for you guys is what turbos should I use for a brutally torquey twin boosted LS truck motor??
Im not really phased by big HP numbers just really good streetable power for towing. I want to go twin turbo just because I can! And it brings the turbos down to a size thats really common here is Australia.
My initial thoughts were a pair of GT2860's, big fuel pump, bigger injectors and a tune. Ive fabbed manifolds and such before so thats not an issue. Even If I can have it making max 300whp REALLY early. Id be happy with that.
But as I said Im new to LS's so let me know what you think!
Luke
The truck currently has a tricked out 4.2 turbo diesel. So I love the torque from driving on boost. It runs 20psi from about 1900rpm.
My question for you guys is what turbos should I use for a brutally torquey twin boosted LS truck motor??
Im not really phased by big HP numbers just really good streetable power for towing. I want to go twin turbo just because I can! And it brings the turbos down to a size thats really common here is Australia.
My initial thoughts were a pair of GT2860's, big fuel pump, bigger injectors and a tune. Ive fabbed manifolds and such before so thats not an issue. Even If I can have it making max 300whp REALLY early. Id be happy with that.
But as I said Im new to LS's so let me know what you think!
Luke
TBH given how cheap BW's are, I see little reason to restrict your options, but a pair of 2860's would probably be a decent starting point.
Or a pair of VF34's or something from a Subaru.
But absolutely no reason why a well sized single turbo wouldnt get the job done, a bog standard single BW S366 might not be far off and they're very cheap, or something like this even better
http://www.agpturbo.com/borg-warner-...3-13009097047/
Id be looking at brand new 2860's or maybe good condition second handers. My goal is to move the power down the rev range as much as possible without choking the big motor with little snails hanging off of it. Ive never really dealt with turbos smaller than t28's. Could I go smaller?
Interestingly this popped up on UK forum recently before they got booted off for advertising. I doubt they are genuine Garrett turbos although they are using their naming schemes
http://www.goatperformance.com.au/
Not really too much different than the APS or GenTT stuff ? Or maybe AVO ?
Maybe if they had some graphs of their GT2871's it might help ?
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Or other small options are a lot of the 1.8t VW stuff, they're bound to be plentiful down there too ?
Will the 1 internal gate on each turbo be enough for this thing to stop creeping boost?
I'll run all the appropriate gauges as Im used to driving by the gauges on my diesel, but ideally i'd want a no fuss tune on this build..
It would make plumbing a lot easier and neater too.
depending on the shape etc, often most castings can be ported/smoothed a little which can dramatically help prevent any creep. Just depends how badly flowing the current wastegate path is at present. Some are ok, some are terrible.
Big issue with that turbo is if you use the gated elbo & the gay 2-bolt inlet horn. I hacked mine up & used a 3" pipe & retained the flapper. You could plate it & run an external. The horn just makes them a little harder to package.
TBH, I would use a different turbo for the reasons mentioned above. As an aside I ditched that system @ built a twin TO4B system with .69 A/R P-trims & it spooled the same & made more power. Ran the same ET on 10psi as the GN's did on 14. Pump gas vs race gas also
Last edited by gtfoxy; Nov 30, 2016 at 12:27 PM.
Could be a silly question, Blow off valves.. Are they needed with this kind of setup? Im only looking to run 9psi. I hate the sound of them, but if its gonna save my motor, Im sure i can muffle it somehow.
Or do as foxy and OEM do, just re-circ back into the inlet tract pre-turbo, post filter and it should be almost silent.
Part of what makes Diesels torque monsters is the short duration cam timing, which maximizes VE at a low rpm. (hoping to avoid a really long discussion within that statement. It's a way deeper subject than this generalization)
The smallest aftermarket cams available for an LS may not be small enough to really target your goal area. However, any smaller than what's available would really like a smaller intake port... and now we're talking money.
However, I would absolutely put a small aftermarket cam in. Many have shown strong (20+ lb/ft) improvements in bottom end torque over the stocker (N/A).
The correct diff gear ratio will likely help make up for any shortcomings in off idle torque.
Keep us posted on results. I'm curious myself.
I'll be running a built 4L60E through a 1:1 transfer case and into a 4.11 rear end. Keep in mind this is a 7000lb truck on 36" tires. Currently the 100km/h revs are about 2500rpm (through factory 5sp manual). Ideally I'd like to see this drop with some overdrive. So maybe stepping up the rear end to a 4.33 will get me that initial torque, but the poor thing will be singing at 110+km/h..
I've just ordered a pair of GT2871's to go on!! So we'll find out soon enough









