Chance EG

I'm being a bit indecisive on this. Engine is finally starting to see some machine work so the trans will need to follow suit soon, need to make a decision soon-ish.

The engine is a B16, will be spinning to 9500, estimated 370-400WHP. Car will be used for spirited backroad driving and autocross mostly, and a few passes down the 1320. Primary goal for the car is just responsiveness and fun. The car will still be street legal, and will still be driven occasionally around town (weekends, etc).

A B16 gearset will be used, and 205/50/15 M/T ET Street-R tires.

I am debating between the 4.4 final drive, or the Mfactory 4.71 final drive (so basically late model ITR spec).





Thoughts on this? On paper the 4.71 final drive looks absolutely perfect, but I'm somewhat concerned with 1st and 2nd gear on this platform from a practicality standpoint (spinning and how quickly I may hit the limiter). The car will spend most of it's time on the M/T Street-R tires, only exception may be the occasional use of 225/45/15 summer performance tires.

TheShodan

iTrader: (14)

IF you're doing backroad driving and "canyon running", 1st gear will be completely irrelevant for that kind of use. When you're saying you're using a B16 Gearset, I take it that you mean that you're using a B16 transmission as a base. If that is indeed the case, than simply changing to the 4.785 (that is the ITR) final drive would be a great idea. But the one thing you have not stated, is which turbocharger family you're using. that, along with the final drive, will determine what will be the best combination, in addition to the exhaust manifold, camshaft, etc.

Most of the people I worked with on B16 engines for HPDE, Circuit, or canyon running, didn't need to worry about going to 9500rpms. It's really unnecessary, and although I'm sure you're preparing for it, rather risky unless needed. These Canyon runners usually run anywhere from 44lbs/min-51lbs/min on that size engine, with a maximum usable rpm range of about 3300-7800rpms. The only reason they would go to about 8800, is if they are rev-matching a corner coming out of turn, and like to Heel-toe their way into the next turn. Going to 9500rpms is just doing so to say that you can. (which is your choice of course).

With all that said, I believe that even the 4.4 can work ok with the B16 because of its already compact gearing. But if you want a little longer movement in midrange power, then yes, the 4.785 FD would do well. Just remember to take into account everything else I just stated.

Chance EG

^The 4.7 was my initial thought, so I'm still leaning that way for the application. As you said, 1st is pretty irrelevant no matter what I'm doing. 3rd and 4th gear are where most of the differences will likely be, and I suppose at that point traction won't be as much of an issue.

I'm still planning on using the GTX2860R Gen 2 .63 turbo from Garrett. Just really curious to see how it reacts on this build. Should flow 43->44lb/min.

I'm not too dead-set on 9500, but I don't see any reason for this build why it shouldn't be (reasonably) easily attainable and the car should still be making plenty of power up there. I suppose if the engine ever popped it would just give me an excuse to go 2L and maybe a slightly larger turbo.

TheShodan

iTrader: (14)

That turbo WILL taper off about 7000-7500 with an OEM camshaft, and about 40lbs/min. Again, there is no reason to worry about power at that high is an rpm. You'll never use it then for that purpose.

Chance EG

Will be using the T1 cams and an aluminum sheet manifold with a 4 -> 4.2L plenum and 5.5 -> 6" runners, 74mm TB. Not sure where that will leave me on the torque/power curve. 3" free exhaust. The turbo will definitely be the first bottle neck as far as flow is concerned, but I want to see how it responds at it's upper limit in the 300 range. Also curious how the T1 cams will respond on such a small profile, as I haven't found anyone else using the T1's on anything smaller than a GT30.

Apologies to anyone on this forum that's tired of hearing me ramble about my money pit . I know you saw me debating on cam choices awhile back, but for this build I think I'm set on the T1's now. If the turbo ends up being too small, I'll address it then.

liam821

My old setup was a stock jdm b16a with CTR cams and JUN valve-train with a T3/Super60 .48AR and a b16a transmission with a clutch-type LSD and the stock 4.4 FD. It was a really small turbo, made like 240whp@12psi with boost dropped off a bit at redline down to maybe 10psi. It made power everywhere though and came on boost really quick. Honestly, the torque and midrange of the small turbo made my wanting of a larger final drive less important - it seemed to always be in the powerband anytime I put my foot down.

When my b16a was NA I was revin' it to like 9500 rpms or something but once it was turbocharged I lowered it to 8200 - half because the power band was soo broad I didn't really need it and the other half I wanted to keep the motor together. It also wasn't really making any more power up there. The T3/super60 flows like ~35lbs/min.

Would I of rather had a 4.7FD? Sure. Did I think it was really worth the effort to get it swapped? Naw.

This. You might see 9500s on the front straight maybe once or twice - but most of the on-track driving is somewhere in the middle. A broader powerband with power everywhere is gonna be faster than a shorter peakier redline. I'd take a smaller turbo with a 4.4FD over a larger turbo 4.7FD any day.

Chance EG

Thanks very much for the feedback Small turbo with the 4.7 sounds like it's going to be awesome. I was never considering using a larger turbo with the 4.7, if anything I know the 4.7 would be an issue if I ever wanted more power (I doubt I will though for this build).

Thanks guys! I'm looking forward to seeing how this build comes together and behaves. Definitely going to be interesting.

TheShodan

iTrader: (14)

No. the 4.7 would not be an issue for more power. It's all in the purpose of the car with the turbo you're using. I use something that's over 58lbs/min on a 4.785 ITR FD and it is by no means a slow canyon runner. This isn't drag racing where you're limited by whether or not you can go to 5th gear or not (I never fully understood why that was bad, I guess. I'm not much of a drag racing fan, so I don't really care to know ). You're now in a more "customizable" setting.

Chance EG

True. Just a difference of what gear you're spending more time in.

And from a drag perspective I'm pretty sure the big goal with gearing is to try to make sure you're in the top of 4th at the end of the 1/4. As close to the limiter as possible without bouncing, so you can use 4th to 100% potential without having to use fifth for the last 1-200 feet. Better to use 4th to 100% of it's potential than have to shift into fifth for only the last second. Same thing as how sometimes on a course people will choose to float the limiter of 2nd or 3rd gear instead of shifting in/out of a higher gear between corners.

Not that you care

2x0

1/4 mile - 4.4

Twisties - 4.7

Balor_Gr

Id say it will depend if youll need to do a 2->1 downshift. If youll never need it it then you wont need a shorter 2nd aka wont need to spend on FD.But it allways depends on the "track"
Money spent on an LSD or independent adjustable bound/rebound suspension will be better spent money

Autoworks

Just wanted to quote that again for the sake of H-T in general...don't mind me.

TheShodan

iTrader: (14)

I love it!

Chance EG

With the build I have in mind I'm expecting to have a lot of juice between 4K -> 9K at a minimum. Should have plenty of window for staying in the powerband. I'll have to double check some of the other plots with similar setups but I think peak torque should be loosely ~4500RPM. Turbo will be the first choke point.

Autoworks

An interesting option I looked at first thing this morning during an email round...GTX2967R

TheShodan

iTrader: (14)

I would stay with GTX2867R over the GTX2967R. For the powerband he's looking for, he'll have a much better time integrating any turbine housings that he may use with the GTX28 series than the 29 series because of lack of availability. The difference in midrange power that this B16 is going to see wouldn't be negatively affected using the 54mm exhaust wheel vs, the larger 56.5mm exhaust wheel, which uses a completely different profile and is not compatible with either the GT(X)28 or GT(X)30 family series. It has it's own profile as it is a newer exhaust wheel/shaft combination. Plus, he'll have more turbine housing options.

If he's doing a bit more straight line acceleration with street use and want's a bit more peak power later, he can always just go with a Banshee or GTX3067R (which obviously uses the same compressor wheel as the GTX2867R, but stays with the GT30 family of 60mm exhaust wheels.) But I would only recommend that if ChanceEG were using a B18C or B20/VTEC.

TheShodan

iTrader: (14)

You'll want that sooner. for canyon running on a B16, a GSC T1 can easily make that torqueband about 3500rpms-8800rpms. That's ensuring you're using the correct spring seat pressure valvetrain.
I personally used the GSC T1s in our DC2 at only 1.8 litres and as able to acheive maximum torque at 4500rpms (over 320lbs-ft) and using a larger turbocharger than what we're suggesting for you.

GSC T1s, unlike Skunk2 Pro1s can work with smaller turbochargers like the ones Greg and I are suggesting. You can run 40-48lbs/min turbos with those camshafts. You'll actually gain better torque lower in the RPM range because of the valve timing events that these cams change it to. IF these camshafts were out back in the early 2000s, I'd have been on them in a second with my 41lb/smin 18G upgraded GReddy Turbo Kit. These cams make major changes in the engine's behavour. You'll find out for yourself soon enough.

I do recommend keeping the plenum size down and keep the throttle body below 74mm if at all possible. Those components are more for drag racing where maximum volume is needed, and as a negative, sacrifices responsiveness because of the amount of air that has to fill the plenum and transition to be combusted. What you would gain in peak power, you'd lose everywhere else. Not every part one gets can work in both worlds.

Chance EG

I've been bouncing around the idea of the 2867 for some time. Plans are still to start with the 2860, as I'll be happy with anything between 350->400WHP.

BMC quoted me a price for a custom mailbox style aluminum manifold, we're looking at constructing a 4 litre plenum with 6" runners.

The S90 70mm throttle body would be my other option, could bump the size down a little bit.

Edit: Yeah good point on the TB, I think the 70mm would be a better idea.

TheShodan

iTrader: (14)

You won't get that with a GTX2860RS, Again, ask me how I know, sir.


Ok. Way over the top for this purpose, and will cause a loss of lower end torque, but, sure, it'll be different.

Hmmmmm, indeed

Chance EG

Not going to lie, the manifold is 50% for aesthetic purposes in the bay. Not a fan of either the Skunk2 Pro or Ultra series manifolds either.

The one BMC should be making will still be smaller and have longer runners than any of the OTS manifolds offered by companies like Golden Eagle or Magnus. Like you said, over the top and will shift the curve north along the RPM, but I don't think it should be too terrible(?)

You don't think the 2860 can do at least 350->370? I seem to see them in the high 300s very often on Focus ST's and SR20 engines.

Edit: Also just going to throw this in here, but the head is being disassembled now and I'm going to be sending it to 4P for port/polish in February or March... Once again, very overkill for these power goals, but I like the idea of a cleaner induction/exhaust path, less carbon buildup, maybe slightly less heat... Figure it'll help the T1 cams and top end as well.

TheShodan

iTrader: (14)

Only time, tuning and actually running on the course/roads will answer that question for you. Just remember, there's more in place than just air ingestion, there's the conversion of the turbocharger to take into account.

Nope. And I own a Focus ST. What you're forgetting is that even on these "Big Turbo" upgrades (yes, Focus ST owners look at these as big upgrades compared to the K03) trying to get over 350whp is taking over 20-22psi of boost pressure with high-knock resistant fuel (usually 93 + WMI) just to get even close to those numbers. The average GTX2867R takes about 21-23psi to reach 334whp on an ST, and if you recall these Ecoboost cylinder heads are way below even the 20+ year old flow capabilities of a basic B16 cylinder head..

SR20DET engines (both Red and Black top) make more TORQUE than anything else, and that was what the drift crowd loved. Because of their lower compression and turbo-designed stock camshaft, they could make 330-350whp because they're were running it at the top of their range even with 93+ octane. They had to. That was the only way the car could really make any peak power was to run the **** out of the turbine wheel, because they didn't want to use anything larger for fear of lag when drifting (That and they were notoriously known for being super cheap assess on average), so a GT2860RS is about as "baller" as they would get. *snicker*..

Even the standard cast wheel GT2860RS is going to make about 320whp at its maximum efficiency of over 23psi of boost pressure. (with the GTX2860R at a close 350whp at similar boost pressure) This is why we're saying to go with at least the GTX2867R. I've already gotten fantastic results with guys using that for the very purpose you're looking to do.

Nope. Again, not when it comes to forced induction. I've had many people port/polish their engines for FI like they did NA, and on average they only made about 20-60cfm more than if they didn't. For FORCED Induction, port/polish really doesn't help. Get the right valvetrain, clean up the ports (to make sure they have some rough textured surface to them to create exhaust turbulence you don't want them smooth), open up the cylinder chambers put the camshafts in, and go. There's no need to spend over $2000 just "''Cuz 4Piston", unless you're doing it for support of the company and bragging rights. (which is a perfectly acceptable reason to do it). But it won't help you for what you're doing.

As someone stated in another thread earlier (I love this term), you're skipping over dollars to pick up dimes. This doesn't need to be nearly as expensive and complicated as though this were a drag race car (be it NA or FI) where EVERY SINGLE CFM Matters. That's because you're not using the amount of exhaust energy for your 4P upgrades to take effect. They help in PEAK power, not in lower end torque and midrange power.

I was one of the 1st people in Honda world to run the T1s (both the 6 series and 7 series) and really, unless you're trying to get what Myles (GringoTegra) is doing, you're throwing your money in the wrong spots.

Autoworks

What exhaust manifold do you plan on using?

liam821

A 4-liter intake manifold is massive! A bit overkill and it will hurt power and throttle response. The Skunk2 Ultra Street (1.8L) is gonna work great for your use - and they're like $299. Heck even a stock ITR manifold with a port to match the throttle body is probably a better option than a 4-liter monster.

This. I've had crazy race heads before and unless you're aiming for massive power you're just throwing your money away.

Chance EG

Your RR manifold. Tial Vband .63 housing, 3" exhaust.

I'll try looking into it more, or see if BMC would bump down the plenum design some. I really just don't like how rough the casting is from Skunk2 on their Ultra series manifolds. I'll consider it though, I already have some other scattered S2 products on the car.

Big thanks to everyone in this thread for the input, and thank you Shodan. I'll take your advice and save the $1500 I was going to put into the P&P and invest it in other parts that I actually need to get the car running.

Edit: Oh, am also heavily considering the 2867 now. Will most likely go that route. I guess the one benefit to being single and broke in a big city is I have plenty of time for discussions like this to modify my plans before committing on the purchases, lol.

Autoworks

I'd suggest not over killing on the intake/head porting side of things to yield minimal results in the area you want to be in.

For the sake of small /high flowing talk...

54mm/76 trim turbine... 48lb/min (things sitting on my desk, Wednesday episode)