Should I put a B16 in my G2?

[Eviloliv3]

Are you guys talking about going turbocharged or sticking to N/A???

it doesnt matter, the shorter geared transmissions will always be faster, NA or Boosted.

that whole theory about LS trannies are better for boost cause you stay in boost longer is lame. Staying in boost longer is just Ricer talk for not accelerating.

if you put the same cars at the line, one with LS tranny and one with B16, and they both hook up, the B16 tranny car will own everytime.

 

[Chuckie Finster]

No, I'm gonna have to disagree with you on this one.

 

[Eviloliv3]

No, I'm gonna have to disagree with you on this one.

please explain why

 

[Chuckie Finster]

Even with a relatively large turbo for the street, a turbo powerband will still be decently broad, and after max boost is reached, you'll be living large. We'll say our 400 hp turbo B18 has a torque peak of 5500 rpm a slow steady drop in torque from there on--torque peak, the point at which you will feel the maximum acceleration. If we shifted, from 3-4, at 7500 rpm with the wide ratios of the LS tranny, gear 4 fall right next to torque peak at around 5600 rpm and almost 2000 rpm of forward thrust until the next shift (if our hearts desire to travel at 5000 rpm in 5th). Now if we had opted for the close ratio VTEC gearbox, the shift will still occur at 7500 rpm, but this time the revs drop to ~6000 rpm. 500 revs off of our torque peak, 1500 rpm of forward thrust. And to make matters worse, a turbo sized to flow 400 whp of air will exhibit a small amount of lag. Approx. .1 to .2 of a second at 6000 rpm on a 1.8L--very minimal, but in racing this is an eternity. The true definition of "turbo lag" meaning the amount of time you have to wait for max boost after your foot hits the floor. So with the close ratio, you never really touchdown at torque peak and you never really make full use of the broad powerband produced by the turbo when it's working.

In our other scenario, however, with a narrow powerband of of VTEC motor (yes I know exactly what VTEC is so don't mention anything that sounds self-contradictory about how VTEC gives you a broader powerband). Torque peak is very near redline on mildly built N/A motor. We'll use 6500 rpm as this is where a lot of VTEC motors like to live. Now if we had the same LS gearbox, and shifted at 7500 rpm, revs would drop to ~5600 rpm. Even though the VTEC cams are working hard and acceleration is good, we will still be waiting a long time for the torque peak and the majority of that 1900 revs is not making maximum use of acceleration. With the close-ratio tranny however, revs drop down to 6000 rpm. Right at the engine's "sweet spot" (actually, it'd be a whole lot sweeter if we raised shift point to 8400--then it shift would fall right into the engine's real sweet spot. But now we're stuck with 7500 rpm shift point for comparisons). And no wait to get into the torque band and the shift is accompanied with a surge of power.

Still not convinced? Ever noticed how turbo cars don't come with close ratio gears boxes and big displacement V8's have wide ratios as well? Close raitio transmissions are not the last word in hi-performance.

 

[Eviloliv3]

If we shifted, from 3-4, at 7500 rpm with the wide ratios of the LS tranny, gear 4 fall right next to torque peak at around 5600 rpm and almost 2000 rpm of forward thrust until the next shift....

Do you even drive an integra?!?!?

you realize that at most, our tranmissions drop about 1.5k rpms at most. in my LS tranny, from 3rd to 4th, it drops about 750 rpms. so if i shifted at 7500 in a 400hp turbo b18, i would drop into 6750. way past my peak torque...

your reasons have merit, but if you test out both of our theories, you might be suprised

Ever noticed how turbo cars don't come with close ratio gears boxes and big displacement V8's have wide ratios as well? Close raitio transmissions are not the last word in hi-performance.

thats cause manufacturers build their cars for the average driver, not the all out racer. even if they did make all out race cars, they wouldnt make them wild enough.

take as an example the Lotus Elise. its basically meant to be a turnkey racer, but it doesnt have any turbo system, its just got a slightly beefed up Celica GTS motor in a 1900 lb chassis. if they wanted to go all out, they would have made the car Turbo.

 

[Chuckie Finster]

Do you even drive an integra?!?!?

you realize that at most, our tranmissions drop about 1.5k rpms at most. in my LS tranny, from 3rd to 4th, it drops about 750 rpms. so if i shifted at 7500 in a 400hp turbo b18, i would drop into 6750. way past my peak torque...

The amount of revs your engine falls during an upshift is not all linear throughout the rpm range. A 3-4 shift at around 3500 rpm will drop ~750. But try to do that same shift at 7000 rpm. You'll notice the revs drop out lot more than 750 rpm. Your LS hits fuel cut even before 7500, how do you know it'd drop down to 6750?

thats cause manufacturers build their cars for the average driver, not the all out racer. even if they did make all out race cars, they wouldnt make them wild enough.

take as an example the Lotus Elise. its basically meant to be a turnkey racer, but it doesnt have any turbo system, its just got a slightly beefed up Celica GTS motor in a 1900 lb chassis. if they wanted to go all out, they would have made the car Turbo.

So you're saying that the Lotus Elise is aimed at the average driver? From its rock hard suspension down to the flat underbody, the '05 Lotus Elise is aimed at the "average driver?" But I would assume the Integra Type R is aimed at a more enthusiastic class since it comes with a close-ratio gearbox and a limited slip differential, right? What about the likes of the MKIV Supra, or the 3rd generation RX-7, or even the legendary Skyline GTR. All Japanese supercars and the performance icons of their respective manufacturers. All turbo powered. None with close ratio gearboxes.

Oh and the reason Lotus chose the Yamaha inline-4 were for different reasons than making big changes to what was already there. Besides, its 190 hp already allowed it to hold its own against cars like the Lancer EVO and BMW M3 and then run circles around them in the road course.

Okay, lets use the RUF CTR-2 as an example if you don't think the Elise is race car technology for the street.

CTR-2:
0-60 3.6 seconds
Top Speed 200+
520 BHP @ 5800 RPM
505 lb-ft torque @ 4800 RPM
Twin-turbocharged Boxer-6
6 Speed manual
Curb weight of just over 3000 lbs
And 14.0" ventilated carbon-fiber disc brakes at all fours bringing the car from 60-0 in less than 110 ft.
In other words, if this isn't a race car for the street...I don't know what is.
Broad powerband and take a look into the Porsche six-speed and the gears are nice and widely spaced (relative to a close ratio box of course). Long time regarded as some of the finest hi-performance automobiles.

Hey, I ain't trying to argue with you. If you'd prefer to use a close-ratio gear box for your turbocharged car, more power to you. It's just conventional logic and in case a newb reads this, they'll know what they're getting into. I know which cogs I'm using.

 

[Eviloliv3]

first of all, i measured the rpm drop at redline

second of all, i was talking about the Lotus being a turnkey racer, not a daily driver. still the manufacturers make it daily driveable enough not to scare off customers

heres my point...

if youve got a car with some power and another one with more power, and they both have the same tranny, wont the more powered one be faster?

now add a shorter geared tranny to both... youll see they will both be faster, but the one with more power will still be faster.

just cause youve got a snail in your engine bay, doesnt mean that a taller geared tranny will be the best bet.

im done argueing, its time for you and i to grab a beer and say "Fuck It"

 

[Baldy201]

First off we need to get straight what kind of fast you are talking about. Acceleration? Top Speed? 1/4? What?

Second, The shorter gears will get you up to speed faster than a long gear ratios.

Here is a graph on torque on the 3 integras LS, GSR, Type R

Here is a pic of the Diffrent gear ratios side by side.

Here is a pic of the Torque after the gearing has been acounted for.

As you can see the shorter gears have higher torgues which is what you want when you race. Torque is what moves the car. Granted the pics are for NA engines. The same will apply to Turbo engines. The Shorter gears may be harder to keep traction but as you can see the Gears are practicly the same where it matters for traction. The Transmission Multiplys torque. So, the higher the number(aka shorter gears) multiply torque that much more then the lower numbers(aka longer gears)

If you want to read more about what I am talking about here is where I got my info from.
Team-Integra.net

 

[Chuckie Finster]

I drove a 1990 LS throughout HS--I cannot comfirm that there was only a 750 rpm drop shifting from 3-4 at 7000 rpm. But calculated, using the actual ratios of the S1 transmission, at 7000 rpm in third gear the vehicle with will be traveling at ~86 mph at the top of 3rd on 23" diameter wheels. On fourth gear at 86 mph, engine speed will be approximately 5300 rpm. That obviously is not a 750 rpm drop--out of place 'cause even that is an extremely "marginal" drop for even a close ratio gearbox. Don't believe me? Want me to show you the actual calculations?

Never mind 'bout the Elise thing. I think we're both missing each other's point on that. I'd still love to have one, however.

Yes, the more powerful one will be quicker and faster. I'm not doubting you on that--did I ever about that? And yes, the shorter geared tranny will also accelerate quicker, all else being equal. It will keep also your revs higher where some engines make best torque. That's also its downfall. It doesn't make use of the powerband available with the "snail" engine and to keep in the powerband there are a lot of shifts involved. Even with a pretty relatively large street turbo under the hood the powerband of a turbo engine is still pretty broad--broad powerband where you can be accelerating. Shift the LS at hi-rpm and it will drop down close to ideal torque and you can continue to accelerate until redline. While doing the same thing with the close ratio will drop you above ideal torque and to hit the spot you'll have to risk short shifting. In drag racing, shifting too much also hurts your time.

And then that brings us back, full circle to my technical post. 8) Yep, we're gonna get stuck in this wormhole pretty soon; I gotta find planet earth. Hey, have fun with your car. :beer:

 

[Chuckie Finster]

Agreed. We aren't denying that the shorter gears will accelerate quicker. We're debating whether to use taller or shorter gearing for a turbocharged engine--and the debates proved to be...*all becomes silent*....inconclusive. Hell, we even got stuck in a space time continuum trying to find out.

 

[Baldy201]

We are talking about two totally diffrent things. Honestly, I have no idea what you are talking about, and Eviloliv and I are saything that the shorter gears are better, no matter the engine, for acceleration. Granted that landing point will have a little to with acceleration, compared to the gain that you get with the shorter gears.

 

[Eviloliv3]

I would love to have an Elise as well. id give my left nut for one.

if you shift at redline everytime you can drop out of your power band. but sometimes you dont have to take it to redline.

case in point:

this graph shows my engines performance before and after some head work.

the 124 graph you can see falls off around 6k rpm. now when i was drag racing, i would go to redline in 1st, 6500 in 2nd, 6250 in 3rd and that would get me the best times. if i redlined every gear, i would be slower by .1-.2 or so. thats because im spending too much time out of my powerband.

if you know where your powerband is, and shift apporiately, then you can get away with shifting well before your redline.

btw, my 750 rpm drom came at my 6600 redline, though it might have been 2-3 now that i think about it

also, i just put in a B16 LSD tranny over the weekend, and let me tell you... the differences are amazing in 2nd, 3rd, 4th and 5th. i no longer "bog" in 3rd and 4th now. just smooth acceleration

Times with LS tranny : 15.8 @ 88
Times with B16 LSD tranny: coming this saturday

:twisted:

 

[hyper98gsr]

first off i agree with the FACT that the shorter geared tranny will have a quicker acceleration. but...to put chuckie's words in laymans(assumed spelling ) terms. the longer gears are better for turbo because it basically needs time to spool. on a short tranny, by the time the turbo kicks in it'll be time to change gears.

if you ever watch a turbo'd car do the 1320 you can see. the car accelerates, then there is a pause, and then the turbo kicks in. with,say a b16 tranny, the car would barely be in gear long enough to reap the benefits of a turbo. now, on the other hand, with a longer geared gsr(preferably) or even ls tranny, the car will spend much longer in boost. therefore giving you more of that power you need.

n/a and forced induction are two completely different things when it comes to gearing.

 

[Eviloliv3]

first off i agree with the FACT that the shorter geared tranny will have a quicker acceleration. but...to put chuckie's words in laymans(assumed spelling ) terms. the longer gears are better for turbo because it basically needs time to spool. on a short tranny, by the time the turbo kicks in it'll be time to change gears.

if you ever watch a turbo'd car do the 1320 you can see. the car accelerates, then there is a pause, and then the turbo kicks in. with,say a b16 tranny, the car would barely be in gear long enough to reap the benefits of a turbo. now, on the other hand, with a longer geared gsr(preferably) or even ls tranny, the car will spend much longer in boost. therefore giving you more of that power you need.

n/a and forced induction are two completely different things when it comes to gearing.

thats assuming the person got a turbo that wasnt the right size for their combination, and you guys forget one thing...

the B16 tranny will let you accelerate quicker, meaning faster in RPMs, well the higher in RPMs you go, the more exhaust gases are being thrown out. therefore spooling the turbo. it theoretically should spool faster becuase you are putting more gases to it quicker than a LS tranny.

the only way to prove this would be to get somebody with a turbo car and let them hit the track with a LS tranny, and then a VTEC tranny (GSR TYPE R B16, doesnt matter)

til then, we should drop it

 

[gettingthere]

these are some good write ups. i didnt know to much about trannys but i'm not confused about turbos now. but reading what you guys are saying (superchargering mine anyway) i want the shorter ratio right. any help would be nice. no i'm not trying to start the arguement again. just trying to learn more to better suit my car. peace.