ZackwiththeEG

Whats happenin fellow Honda Tech members.. I have a question. More or less a "who's done it".

So a friend is boosting his LS. Stock internals, stock head. Couple bolt ons.. Intake manifold etc. To keep a long story short, he wants to use a S366. Granted its a huge turbo, and I would imagine overkill for a stock motor, but has anyone ever used one on a stock LS, LS/VTEC even? He is using a tubular top mount.. not sure on runner sizes but from the eye, they're nice sized. I personally havnt used a turbo quit that size, so I'm not sure on which direction to point him in. Granted, I imagine it would make good power, and also sound AMAZING.. But, no one wants to wait until Christmas to make any boost. Anyhow, everyone's opinions/facts are greatly appreciated.

Thanks!

boosted94gsr

S366 + top mount on stock ls = worst idea ever

You'll have the worst powerband ever.

TravisBiggie

short ram, or ramhorn, with a small turbine housing (.70ar) not the .88 or .91 ar that come with the ebay ones, might perform okay, but still will be laggy with a big 66mm wheel

jdm_h22

In short, yes it can be done. Will he like the results? Probably not.

Here's some rational advise. Determine the purpose for the car and then reasonable horsepower goals (keeping in mind the restraints of a stock motor).

THEN, pick a turbo that meets those needs.

ZackwiththeEG

Thats what I had assumed. I mentioned to him using a nice ramhorn or log manifold even, but hes hell bent on using that top mount. Granted I can't blame him, it's a nice top mount, and a pretty penny assured, but I agree with you.

boosted94gsr

Some people learn the hard way I guess lol.

ZackwiththeEG

Right, I did tell him I'd probably want to use a ramhorn or nice log manifold even, but hes hard headed, needless to say. I knew no matter what it would be laggy, I just couldn't give him a honest opinion, so I ran here😂

ZackwiththeEG

Oh absolutely it could be done.. But again, who wants a half pound of boost at like.. 9 million RPM lmao. I again made mention of using a nice 50 trim, or even a GT35..

2kdrift

sounds like he wants a racecar but doesent wanna swap the engine. top mounts were more designed for drag then anything else kinda pointless on a stock block and an LS at that (not the best combo for top end power) same thing with the turbo it would be much more well suited on a drag car

with that setup power band would be about 6k+ and rev limit on a stock LS is about 8k so yup pretty horrible power band and very hard to use on the street. Id take a log manifold with a much smaller turbo any day

ZackwiththeEG

Sadly lol, I took that route myself being hard headed and learning the hard way. Therefore I learned.. Don't be afraid to ask questions and take advice from veterans lmao. Ive worked on Hondas in general for years, but I havnt had the pleasure (truthfully headache..) to work on many many turbo cars.

ZackwiththeEG

I agree 100%. When the question first arose about boosting his car, he came to me with kinds of questions, concerns etc. Granted, he has the money to build a Bseries. So I made mention of doing something simple, yet nice. Pistons rods etc., little headwork with some cams and go make 400 hp no problem. But, he isn't concerned with making that or going through the "trouble", but wants to keep nice things. As I stated earlier, I really had felt like that S366 would be way to big, as you stated powerband wouldn't be but like.. Maybe 1500 RPM or so. Rod bolts for a stock LS will stretch after 7500, hence the 7200 Stock rev limit. I personally would want to go with a good 60-1 or so, and a nice ramhorn or log manifold.

Geis

Hussian vtec I believe had a 450ishwhp bone stock b20...and that's with b20 paper sleeves. Your friend might actually be able to squeeze 350-400 out of it and still have it last a somewhat decent amount of time.

I was going to suggest a 7.5 redline, but as prior stated he won't be hitting power until around 5-6k. Still more fun than stock lol

ZackwiththeEG

Oh wow.. I've litterally never seen a stock B20 bottom end handle that sort of power lol. I helped put together a B20 vtec that made 375(ish?) on 15 pounds, stock bottom end versus rod bolts of course, but that motor didn't last long at all (which of course we knew it would happen). Now, ive seen multiple stock LS' make inbetween 250-300 and run forever. My stock LS made 220.. Granted it was on 8 pounds with REALLY cheap stuff, so I was to tickled link lmao. But besides the point, he hasn't told me a power goal, but i believe 250, 275 is a very reasonable power goal with a stock LS. I'm sure I'll convince him to stray away from the S366 idea, ima lean him more forwards a GT35 or a good entry level precision. I feel like with his top mount he could still make good power..

ZackwiththeEG

2kdrift

GT35 is still a bit large I would say more like a GT30 for stock block, hmm still runnning stock pistons yea a GT35 is way to large 50 trim would be overkill really, even a 45 trim or gt28 would be more the size on stock pistons

ZackwiththeEG

That is true, I just would have recommended that for my friend, because another friend, same guy that had the B20V set up I mentioned earlier, used a GT35 on his stock LS and it did really good considering it didn't make full boost until 4, 4500, if I remember that correctly. But yes a GT30 would work perfect as well.

2kdrift

theres "good" and theres better.........Gt30 is more for a built block, stock pistons anything past 300hp is pushing your luck rods would be the lowest failure point. I would be looking at something smaller even then a gt30, gt30's are capable of well over 400hp

ZackwiththeEG

Well of course.. I stated earlier about 250-300 is good for a stock LS. I wouldn't want to shoot for more, and I sure hope my buddy had enough sense not to try that either lol. But yea, from what I've seen and understand, ringlands will break, rod bolts will stretch, it'll crack a sleeve etc., or really kick the bucket and throw a Turkey leg. Either way, he'll understand thoroughly what would and wouldn't be good, facts and opinions. Its obvious this is first turbo application and doesn't have much knowledge about it, But with my help and you guys help he'll check out alright. The guy Thats gonna tune his care is an excellent tuner here in NC, so again I believe hell be alright. But off topic.. A GT30 would probably be a little big on paper.. But I'd use it personally. I believe itd spool at a decent RPM, make nice power and besides, later if he decided to make more power, he'll have the turbo for it.

2kdrift

agreed you have seem to have a very good understanding, my point is I would personally rather have a faster spooling turbo given the power goals.

as far as "more power later" you are removing the block so turbo will need to come off anyway, spending a bunch of money on building the block so you could easily sell the old turbo and upgrade to something bigger at that point.

just my .02

ZackwiththeEG

I'll match your 2 cents lol. Very good point made.. There definently isnt an argument that would be valid, because your right, head would have to come off for work, turbo removed yaddayadda, so I reckon he could turn around and sell it.. Or keep it, Or order a bigger one, hell I don't know lol. To each is there own after all!

Schister66

Full boost by 6k, redline at 7200 and no matter what, its limited to 3-350whp at most before that stock LS will give up on life. Get a smaller turbo and ditch the topmount

jdm_h22

I don't think anyone here is big fan of the "run a bigger turbo than you need so you have room for growth when the block is built" mentality. I can understand this logic to a degree. But like most things it can be taken too far.

Definitely use a turbo that you can put in it's "efficiency range". I believe thats the term.

I'm currently running a gt30 on an lsvtec motor. It performs incredibly well. Boost comes on at 3,500 and doesn't stop until 8,300. I made 405hp / 330tq this year.

If that gives you an idea of where a gt30 can easily put you in terms of power... In fact, I feel like out could go even further.

Schister66

An S256 would be another good choice. Its small enough to be fun on stock but has the legs to make upwards of 500whp. Check the first link below - anything laggier than that wouldn't be any fun on a street car, especially if you're capped at 350whp on the top end anyway

B16 with S256 - 398whp/258tq @18psi

GSR with 57 trim - 440/310 @18psi

GSR with 57 trim - 368/228 @11psi

GSR with STC Hunter - 380/260 @10psi

B16 with 57trim - 390/250 @18psi


and since 300whp is more or less the cap, here's how i'd achieve it

GSR with GT28 Journal Bearing - 300/222 @10psi

Schister66

Just to throw one more on the pile, here's my old build LS/VTEC with an S256. This graph was only at ~16psi

ZackwiththeEG

I myself try to have that mentality, but not enough to over shoot it. I believe in having good enough parts you may not technically need, but later on when you go bigger you already have the potential set up. And oh of course.. Talking to a few friends who have used GT30s and GT35s are all happy with them.