LOL @ some turbo cars....
LOL @ some turbo cars for making alot of power, but only at the last bit of their rpm range. If ya'll had just bought the right sized turbo, you'd make less hp, but in a more usable rpm range. I've been watching youtube and streetfire all morning and I find this phenomenom funny. That is all.
K series 626. That's right. It's got a K in it.
Were they Hondas?
yep. A couple of supras. Mostly hondas.
K series 626. That's right. It's got a K in it.
Those are the same dudes who are quick to claim their sh!t is quick. Dyno queens are only quick when the turbo kicks in. For those 2k rpm, their power rains supreme. Anytime before that, USELESS
K series 626. That's right. It's got a K in it.
DAMN you might be on to something. wonder why nobody has thought of this before you
I'm laughing at you. Remember that.
K series 626. That's right. It's got a K in it.
No need for that, my setup spools at very low rpm. thanks though
How low? and what's your rev limit?
K series 626. That's right. It's got a K in it.
we were discussing this last night as well.
Depends on what it is really and the setup. If its a 1200whp supra, there is no such thing as powerband. A 3.0l or 3.5L can only spool so much, rev so far.
Same with the EVOs , same with Hondas, etc.
There was a guy on HT with a SOHC D series that was making like 430whp on a built motor with a 30R. His power band was useless. He was revving to 8500 and i think he hit full boost at 7000rpms. He didnt make over 200whp until 6800rpms. so his car only made peak power for maybe 1 second.
What was worse was his gearing. If he shifted he fell out of boost by like 2000rpms.
But everyone on HT (all the noobs) were like "OMG THATS CRAZY IM DOING THAT TO MY D SERIES!!!!".
Little did they know that the same car making 250whp with a T25 would smoke that car from stoplight to stoplight.
Same goes for guys that buy those Ebay turbo kits with the t3/t4s on them. Unless you have an h22 or F motor, those turbos are too big for stock motors. Power is too peaky, too laggy , etc.
Most people want a street car, and a street car is better served by a proper spooling turbocharger. Not max HP.
If you are into highway pulls, then it doesnt matter as much. Because the "area under the curve" doesnt mean as much to guys who are going to be high in the revs anyway.
Go look at the 700whp EVO we just tuned, his powerband is really laggy. But he doesnt care, he does highway pulls from 6500-10,000 rpms. An thats where he makes the most power.
Now if he was on a road course, a stock evo would wax him.
What you are mentioning is simply AREA UNDER THE CURVE, the question is, how big is that curve and what is the car being used for.
Even gearing would take a huge account when it comes to making that far in the rpm band. If you gonna run a turbo for the purpose of max speed, why do it with very short gearing? With longer gearing (particularly the final drive), whenever that turbo decided to spool, you'd definately have more time in between shifts to have some decent acceleration. Let's say for example that someone was running a B18C1 fully built and decided that for their turbo set up they wanted to run a type R trans with that really short 2nd,3rd,4th and 5th gears mated to an even shorter 4.40 final drive. There's no way in hell they're gonna do any decent acceleration numbers for the fact that the turbo still haven't had a chance to spool. But if there was a possiblity to gut a VX or a DX trans and swap it into that same GS-R or Type R case with an LSD then there's possible okay acceleration is possible, but only for straight line purposes. That particular turbo set up would be slaughtered in an autoX event and even still from stop light to stop light.Originally Posted by Batlground
The thing is that most the high hp cars that has been built up for the street has a power band not suitable for the street. but for a really long stretch of road. Unless you have a spotter a mile ahead and a really long stretch of road, that powerful car is useless, flat out.
K series 626. That's right. It's got a K in it.
Actually a shorter gear ratio would be better for a car with a narrow powerband. If the shifts are too long the car would spend too much time trying to get back into its narrow powerband and have even more lag.
But thats what you get when you try to make 500 hp on 2L or less. I love having an easy 350 hp out of 2L but its hard to compete with displacement.
exactly.
this is why a ITR trans on an LS engine makes it so much faster without even adding horsepower.
My ideal street car (honda) would be a 300whp GT2871R .86 with a ITR trans and LS fifth gear (for cruising)
Short gears is a MUST for NA cars (faster into the powerband, and when you shift, you fall back into the meat of your powerband aka rev drop) and most sub 300whp cars the short gearing is great. It makes the car feel so much more responsive.
It used to be that people thought the LS tranny was supreme for turbo setups, but now, everyone universally agrees the GSR is the best all around tranny. The LS tranny was just too long geared, and too much rpm drop in between shifts, and just too tall.
Heavier cars will want a shorter geared tranny, lighter cars can get away with longer gears.
It really all comes down to shift points, powerband, setup, displacement and rev limiter.
You can have a long geared trans if you rev to the moon.
So you are saying that a short geared transmission means the turbo wont spool as fast?Let's say for example that someone was running a B18C1 fully built and decided that for their turbo set up they wanted to run a type R trans with that really short 2nd,3rd,4th and 5th gears mated to an even shorter 4.40 final drive. There's no way in hell they're gonna do any decent acceleration numbers for the fact that the turbo still haven't had a chance to spool.
You have too many holes in your example, we would need to know what turbo, what power level, what Rev limiter, what chassis, etc.
A short geared trans is ok in a Integra body under 300whp. A short geared trans in a 500whp Integra is going to top out too fast, and will cause traction issues.
Now flip it, a CRX could get away with a longer geared trans because of its weight being so much less.
but there comes a point in horsepower level where the gearing gets closer and closer to the same.
What you really need to do is get a dyno, weigh the car, dtermine your rev limit, and plot shift points that are relative to your tranny setup
With my last setup it would spool 9psi pretty easily by 2900-3000 rpm, my new setup should be similar but have better top end. I'm revving to 7300 rpm. I also run short gearing and so I don't lose much power during shifts.
FYI you are using the term acceleration wrong.
Acceleration is an objects change in velocity over a certain distance/time
a = Dv / Dt
on the mx3 i had with the t3/t4 setup it didnt spool until almost 3500-4k, and the redline was 7k max on the bp. It was useable power just not what i really liked, and i couldnt enjoy the pull. But with the old setup with the vj11 it would run out of breath at 5k. My next setup on my gt, im gonna use a vj20, maybe 23 if i can get my hands on one. But its all about knowing what your working with. it seems to be a trend nowadays to just throw the biggest turbo on a motor and some injectors, and afc and go... its so retarded if u look at the mod list of some peoples boosted cars.
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