sti clutch in 2.5 or 2.2 trans

[LSiTo5Revo]

well i have a 2000 legacy L. I'm swapping this one out as well. only this time im putting the 2.2/2.5 boxer mix up in it. i was doing some reading and ppl that have done this say the 2.2 or 2.5 stock clutch cant handle the torque from the build. so to ensure that i dont have slippage, i want to put an sti clutch in. would the clutch fit without any problems if i were to put it in either a 2.2 or 2.5 trans. 2.5 trans wld probably be a better match but if the 2.2 blows apart ill be huntin for a 2.5 trans.

[mike-tracy]

Um you'd need a turbo tranny for the STI clutch disc and the STI flywheel as well for it to work. Then you'd have to mark where the flywheel hits the ribs in the turbo tranny's bellhousing and grind those down. It's been done before, search on NASIOC.

[rougeben83]

sti clutch won't work anyway because your 5mt is a push type vs. pull type accutation. Only the WRX transmissions can use an sti clutch with modifications because it too is a pull type.

[jey]

Better to just get an Exedy Stage 1 or something - mine holds really well with the turbo setup.

[StatGSR]

Just get an aftermarket clutch for a N/A 2.5. There are plenty available.

[LSiTo5Revo]

well thats unfortunate, i guess ill be buying the stages now. Thanks.

[StatGSR]

are you talking about a high comp hybrid? cause i don't see that doing much destruction, nothing a stock 2.5 clutch couldn't handle....

[LSiTo5Revo]

well the 2.5 block with the 2.2 dual port heads. Getting the cams sent out for welding and lathing. supposed to be "nasty". Its supposed to have a fairly high compression ratio. every one that i found that did it, always gave a different result for the compression ratio. I think theres posts about it on here actually.

[StatGSR]

I know about the motor set up, i was going to build one at one time actually. but yea, the power from that would hardly be anything that a stock 2.5 clutch couldn't handle. but like i said, if you want a beefier clutch, just an aftermarket one for a 2.5.

my real question is why you would go from a EJ25 to an EJ25/22 hybrid. not worth the time or money IMO.

[rougeben83]

well the 2.5 block with the 2.2 dual port heads. Getting the cams sent out for welding and lathing. supposed to be "nasty". Its supposed to have a fairly high compression ratio. every one that i found that did it, always gave a different result for the compression ratio. I think theres posts about it on here actually.

My old Exedy Sport clutch (or stage 1 or whatever they call it nowadays) held up to 260ish hp at the wheels (that's around 350hp at the crank) just fine for almost 2 years, including a couple of SCCA events.

That clutch will be fine for your purposes.

[LSiTo5Revo]

Those who have done this build say they were extremely satisfied with the outcome. not sure where i found this one but one guy said he could dust wrx's all day. and for being n/a i am desperate for more power. Turbo is just too much up keep and is fairly exspensive. sry to sound cheap. Another thing that i found was an H6 swap. Iv found many svx's in my local bone yard. But i figured itd be easier to do the 2.5/2.2 build.

[StatGSR]

^ those guys are lying... seriously, if you have a 2.5 in your car, build that, its a better motor. Even most guys that have done the hybrid will tell you (high compression isn't everything). Its a great upgrade for those with a 2.2 in their car, you don't have any wiring to do or anything just "slip" in the new block and your done. But with if you have a 2.5 in your car, you will likely have to mess with the wiring so you can use the 2.2 heads and intake manifold. Have you read the huge thread about this motor on nasioc???? http://forums.nasioc.com/forums/showthread.php?t=631527

Seriously, build your 2.5 and keep your current heads. talk to delta and get some cams, get a thinner head gasket and bump up the compression. It should be better and it will be less of a hassle when compared to the 25/22 high comp franken motor.

[StatGSR]

A few notable quotes from one of the "pioneers" of the HCF setup...

http://forums.nasioc.com/forums/showpos ... tcount=112 (http://forums.nasioc.com/forums/showpost.php?p=8687581&postcount=112)

http://forums.nasioc.com/forums/showpos ... tcount=161 (http://forums.nasioc.com/forums/showpost.php?p=11244435&postcount=161)

http://forums.nasioc.com/forums/showpos ... tcount=238 (http://forums.nasioc.com/forums/showpost.php?p=26392284&postcount=238)

http://forums.nasioc.com/forums/showpos ... tcount=240 (http://forums.nasioc.com/forums/showpost.php?p=26565312&postcount=240)

http://forums.nasioc.com/forums/showpos ... tcount=303 (http://forums.nasioc.com/forums/showpost.php?p=32176687&postcount=303)

[LSiTo5Revo]

wev done two cases of putting a 2.2 in legacies that came factory with a 2.5. My 97 lsi and a 99 outback. and as far as i can remember we didnt really have to change or rout wires. Im lieing... the only thing we did have to change was the wires for the coil. even so i cld be wrong with the wiring as the gen go's up.

[StatGSR]

either way 2.5 heads > 2.2 heads any day of the week.

[rougeben83]

in terms of head flow, the 2.5l heads (especially the DOHC ones), flow more than what even a modified 2.5l shortblock would need, at least according to the people that have tested those heads on a bench...the main limitations are the cams with valves and springs after that.

[LSiTo5Revo]

i have some homework to do. as it was posted once before. just have to look up specs on parts. dual port would clearly have higher flow than single. could it be possible to ream out the exhaust ports for even higher flow? or does that just sound senseless..

[jey]

dual port would clearly have higher flow than single.

I thought this too but apparently that is not necessarily true - still can't find any numbers to support it either way.

[StatGSR]

i have some homework to do. as it was posted once before. just have to look up specs on parts. dual port would clearly have higher flow than single. could it be possible to ream out the exhaust ports for even higher flow? or does that just sound senseless..

Not sure what your getting at here but.....

2.2 dual or single port should have nearly identical flow.

2.5 SOHC or DOHC will have more. both the SOHC (EJ251) and DOHC 2.5 (EJ25D) are dual port.

Stick with your EJ251 and get a set of cams..... https://sl-i.net/FORUM/images/imported/2010/11/deadhorsefast2gif-1.jpg

[LSiTo5Revo]

now why would they go and change the design of the exhaust port? a dual 2.2 to a single 2.2. if i had a guess id say the purpose of that would be to lesson the exhaust flow. (PZEV). and they say earlier pzev's weren't exactly the most fuel efficient. as years went up id assume they found ways of being eco friendly and efficient with the fuel consumption at the same time. (thats my theory).

I got a bangin idea. someone with a dual port will take a giant balloon and put it around their tail pipe and time it til it pops. then someone with a single port will do the same. and then youll have it...a test result, compare times and then see which has more flow. :grin:

[rougeben83]

Or, you take one set of heads, put it on a flow tester, and see the max CFM its able to flow :).

[StatGSR]

this thread is literally starting to make me angry... maybe i need to take a break from helping people....