jonathan13

i plan i boosting a stock d6y7 to around 7 pounds and i know the y7 tranny is way too long for any type of good acceleration on a NA motor but would it be good with boost since it has such long gears and it will stay in boost longer? thanks for the help. please no flamming. if you dont have anything to say that will be useful then keep it to yourself

TooManyTickets

if your talking about that automatic tranny then your quickly going to end up with a pile of scrap metal.

patrickd_21

im boosted right now at 270 whp on a y8 with a y7 tranny...and let me tell you that the y7 tranny is pure ****!....i fall out of boost like crazy all the time cause the gears are so long.....get a y8

jonathan13

why in the world would i be talkin about an auto tranny lol. no its a manual. i have a z6 tranny layin around but it has a grind. could you explain a little more? im a noob to boosting and this will be my first boost project. what do you mean it falls out of boost? thanks for the help

klungemonger

That would depend on how you set up your turbo kit, nobody can make a cover-all statement that "you will fall out of boost with a Y7 tranny". First of all there are more than 1 version of the Y7 tranny. Hatchbacks had a 3.76 final drive, coupes came with a 4.06 f/d. So one is better than the other. But what he was saying is because of the longer gears, when shifting the RPM will drop farther and on his car it drops him below where he spools up.
The bottom line is that shorter gearing ALWAYS gives you faster acceleration regardless of boost or N/A. But it will make you shift sooner and possibly make you shift more times in the 1/4-mile which can affect your times, and of course reduces your top speed in each gear. there's always a trade-off.

03akkord5spd

the y7 gears are too long for boost. when you shift into the next gear, your rpms drop so much, that you loose boost -"fall out of boost"- which is why the y7 tranny is bad for boost. get an ex/si z6/y8 tranny...

big-cat

you know i would think a y7 would be good when you get to the upper levels on a d-series......say like 300, maybe 350+.
but i guess it all depends on what your motor's head can rev to and the turbo size.

patrickd_21

ok well my setup is fully custom, i have a gt2861rs and a fully built y8....so essentially when you boost a honda you don't make much power before 5500 rpm for example...so when i shift for example from 2nd to third i got to 7500rpm and then shift into 3rd but then my revs drop to like 5000rpm for example cause the gear is so long....so then i have to wait until i hit power again at 5500 rpm...whereas if i had a y8 tranny when i shift from 2nd to 3rd i might fall to 5800rpm so ill be in the spot where i still make ALOT of power

klungemonger

Well yeah a 2861 on a D16 is going to need the revs...if he does something milder like a T25 series it might be fine for him. Less peak but more in the midrange will let him have the option of either tranny. I still agree though that the Y8 is a funner trans to have for typical street use.

jonathan13

i purchased a used kit that has a garret t3. i know that is very vague but thats the only info i have at the moment.

klungemonger

You should be able to read the A/R ratios on the hot/cold housings. You'd have to remove the housings I guess and measure the diameters of the inducers & exducers to get the trim.

big-cat

with my egay t3(42 on the hot side and 48 on cold) my peak TQ is right around 4500, though i guess you all are right because my peak hp is around 6000ish. and when i shift from 1 to 2 (keep in mind my redline is 6800, damn y7's) i drop to about 4000.

so i guess, essentially a y8 is better in just about every aspect(unless it was a t25 turbo but, that would be for going slow or more DD)

klungemonger

Peak hp is right around where you should be shifting at, and in the best case peak torque or close to it is where you want to end up after shifting.

PS big cat- in your sig it says the CX is the longest tranny ever...not so! Check out the old VX tranny with a 3.25 final drive that in 5th was only at 2000 rpms at 60mph! Capable of 180mph at redline!

jonathan13

well thanks everyone for the info. i guess ill be putting syncros in the z6 tranny i have

big-cat

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by klungemonger &raquo;</TD></TR><TR><TD CLASS="quote">Peak hp is right around where you should be shifting at, and in the best case peak torque or close to it is where you want to end up after shifting.

PS big cat- in your sig it says the CX is the longest tranny ever...not so! Check out the old VX tranny with a 3.25 final drive that in 5th was only at 2000 rpms at 60mph! Capable of 180mph at redline! </TD></TR></TABLE>

i have that same final drive i am 90% sure. but if you are correct i remember useing a d-series tranny calc and it said i could hit either 180 or 170 idk, either or they both suck.

klungemonger

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by big-cat &raquo;</TD></TR><TR><TD CLASS="quote">

i have that same final drive i am 90% sure. but if you are correct i remember useing a d-series tranny calc and it said i could hit either 180 or 170 idk, either or they both suck.</TD></TR></TABLE>

No the lamest of the Y7 trannies had a 3.76 final gear, but because you can get up to 7K redline then you can theoretically hit the same top speed in 5th, although you'd never make enough power to get the car up to that with that kind of gearing, you'd get owned by physics!

muletester

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by klungemonger &raquo;</TD></TR><TR><TD CLASS="quote">No the lamest of the Y7 trannies had a 3.76 final gear, but </TD></TR></TABLE>

It's actually 3.72222, which comes in the 96-00 cx

hx trans has the same gears as the cx trans, except it has a y8 case.


Get a 4.25 final drive or get an ex trans. It will make a BIG difference.

blk92_d16

Yep, my VX tranny owns me! People have said (current turbo'd D owners) that the simple long-gear to short-gear swap to increase your 1/4 mile times by at least a half second...

muletester

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by blk92_d16 &raquo;</TD></TR><TR><TD CLASS="quote">Yep, my VX tranny owns me! People have said (current turbo'd D owners) that the simple long-gear to short-gear swap to increase your 1/4 mile times by at least a half second...</TD></TR></TABLE>

it will make more of a difference if you have a cx/vx trans.