ej25/ej20tt hybrid

[ej25tt]

well, after the b4 conversion nightmare, i already have the wiring and everything complete, so thought id build a hybrid from the 2 motors.

ej25 block, bored 020 oversize, wiseco pistons, eagle h-beam rods, acl bearings and rings, ej20tt heads, custom exhaust manifol and turbo back exhaust, hyperflow tmic, port matched intake manifold (for now till i can get tomei quad throttle body), and ecutek tune.

chasing 225kw/300hp atw...

has anyone actually done this, or got 1st hand knowledge of such a hybrid. or similar...

[Jim]

To be honest, the TT turbos would pose a fair restriction on a 2.5L motor. The motor would be choking at high RPM, considering the exhaust turbine size on a TT turbo is a bees dick bigger than a 20c peice. Not to mention on primary turbo operation, i dont think it would be sufficient enough to supply the engine.

If i were you, stick with the 2.0 as its what the system is designed for. If your going to do a 2.5, single turbo it.

[jdm rsk]

twin turbo are rubbish. i owned JDM RSK and i am glad its long gone, also the 2.0l engine are a better and stronger engine then the 2.5l

if i was you i would keep as far away as you can from the sequential twin turbo engines...single turbo is the only way to go

[ej25tt]

i bought the front cut for my dads brumby. but his going the new turbo diesel. so i threw the ej20tt in my car until the turbo 6 is finished. and the bottom end was fucked when it started. so i thought i'd build this to see how it goes. has anyone actually had one or seen one. or are these opinions? i appreciate your input.

[Jim]

This is advice. If your going to stay TT, keep it a 2.0.

However, if you keep it TT i would'nt recommend it as your daily. You will spend alot of time and money keeping it operating. Im telling you this because i have done it. I loved my TT but spent way too much money and time on it and it got me nowhere. Theres just so much that goes wrong with them becuase they are simply getting too old and its such an intricate system. If your going to build a 2.5, single turbo it. I have already told you why a 2.5 wont work with TT.

[hawks123]

x2

As others have said don't bother with the TT.
I had problems with my B4 which i never really got to the bottom of.
The TT is very good in traffic, but if there's issues they are very hard
and can be expensive to fix, if you can fix them. All the many solonoids and
valves are getting very old now and are sure to fail at some stage.
A single turbo 2.5 is the way to go IMO.

[Robbks]

Apart from saying that single is the way to go.
the engine build itself sounds fine.

but if you're determined to keep it TT i'd gut the system and run it in parallel, full time
i.e rip off the secondary up-pipe and build one without the ECV junk in it
Try and get some VF26/27 turbo's as they are basically exactly the same size.
on a 2.5, it should have suficient exhaust flow to give reasonable boost response.

The intake will let it all down as it's a nightmare path for teh air to get friom teh AFM to the turbo's, but a custom alloy intake could be built to increase flow, i have a spare, cut up TT itnake pipe that i was going to use as a template to make a custom one for my TT.

you could then easily run a standard WRX ECU and get rid of the black box of death, and if the project fails just whack on a TD05-20G and stock Single turbo headers/ up-pipe/ exhaust

[sooobi]

go single!

[Dropz]

Single turbo engines, both 2.0 and 2.5 have alot more potential than twin turbos and have alot more readily available performance parts. Also easier to tune from what I have heard from some dyno guys.

[ej25tt]

Thank you all for your posts.

However, read as many of the forums here as you like, they are 99% single turbos. Which is tried and tested yes. But not individual or different.

I'm doing this as a project. Something different, and if the TT setup fails, I can just single turbo the engine, and I've got a good unit capable of 400hp. Like everyone else. But, noones done 200+ kw atw with a TT yet, so i am going to have a go.

Just keeping myself amused, while the H6TT is being all put together. (as that is being done meticulously.) this is just some fun, so im going with it. coz once its tuned (finally picked it up today with new engine), then i am going to try and develop a simpler sequential system for the turbos. which is not so dependent on solenoids etc...

might never work, but at least i can say i tried hey...

again, thanks for all the posts. will keep you updated.

[Jim]

Your not going to get even near 200kw without some mega mad scientist shit going on and big dollars.

My GTB was heavily modified

- Forged internals
- EJ20R
- B4 VF33/32 turbos
- Parallel fuel rails/SARD FPR
- 2.5" Dumps to 3" merge with Fujitsubo muffler
- Custom up-pipes
- Custom intake
- Bigger TMIC
- Removed solenoid operation of ECV
- Silicone TMIC hoses
- Manual Boost Controller (20-24psi)
- Bosch Fuel Pump
- Lightweight Crank Pulley
- Completely reco'd and serviced heads

The best i could get out of it was 165kw atw with a peak of 20psi. Would have been good for probably mid to late 13sec pass. Which was dissapointing considering the money and time i put into it. Eventually i got to a point where to get anymore power out of it, i would have had to spend big on aftermarket engine management and the rest of it. Not worth it for such minimal gain.

Its a challenge thats not rewarding.

If you were going to do it regardless, why ask for anyones opinions if your just going to go against the grain anyway?

If i had time and money to modify a TT i would ditch the primary turbo for a supercharger and run a setup very similar to the VW 1.4 TSI. Now that would be a interesting challenge with a 2.5L.

[ej25tt]

If i had time and money to modify a TT i would ditch the primary turbo for a supercharger and run a setup very similar to the VW 1.4 TSI. Now that would be a interesting challenge with a 2.5L.

Now thats an interesting thought. Don't mind if I take advantage of your ingenious? Seriously, I love that idea. And, for everyone. I wasn't intending to 'go against the grain' as such. i was looking for feedback, so as i would have an idea on power figures, so as i didnt spend $20k on something 5-10kw better than a $5k engine. I am tampering with a TT because the engine won't go to waste when the 6TT goes in. It will be put into something lying around the workshop here somewhere. But Jim, thats some inspiration. anything untried is individual. I love it. I didnt go single turbo, because if thats what i wanted, there are thousands of WRX's modified out there for sale. I would of just bougt one of them. i enjoy the unknown. Thats why im also about to build a custom Kenworht SAR with a 12V71 with quad turbos and twin superchargers.Because its different. But thank you all for giving me information regarding what to look for, what to look out for, and what to expect. that is why i asked for the opinions!

VW 1.4TSi, sounds like an early GM type set-up. Does it work similarly? (turbo fed blower?) im aware it wouldnt be scavange fed, but ultimately similar set-up right?

[Jim]

Heres some info!

"The mechanical supercharger compressor, driven at 1.5 times the speed of the crankshaft, mainly operates at low engine speeds from tick-over up to 2,400 revolutions per minute (rpm) to increase low-end torque. At engine speeds just above idle, the belt-driven supercharger provides a boost pressure of 1.2 bars (17.4 psi)**. The turbocharger assumes full effectiveness at middle revs, and the engine map disengages the clutch-controlled supercharger at a maximum upper limit of 3,500 rpm; the supercharger will then be bypassed once the turbocharger spools up and reaches sufficient speed to provide adequate boost in the upper rev-ranges"

** 17.4 PSI!!!!

http://www.youtube.com/watch?v=20qqavckWdw

[ej25tt]

Your not going to get even near 200kw without some mega mad scientist shit going on and big dollars.

My GTB was heavily modified

- Forged internals
- EJ20R
- B4 VF33/32 turbos
- Parallel fuel rails/SARD FPR
- 2.5" Dumps to 3" merge with Fujitsubo muffler
- Custom up-pipes
- Custom intake
- Bigger TMIC
- Removed solenoid operation of ECV
- Silicone TMIC hoses
- Manual Boost Controller (20-24psi)
- Bosch Fuel Pump
- Lightweight Crank Pulley
- Completely reco'd and serviced heads

The best i could get out of it was 165kw atw with a peak of 20psi. Would have been good for probably mid to late 13sec pass. Which was dissapointing considering the money and time i put into it. Eventually i got to a point where to get anymore power out of it, i would have had to spend big on aftermarket engine management and the rest of it. Not worth it for such minimal gain.

Its a challenge thats not rewarding.

If you were going to do it regardless, why ask for anyones opinions if your just going to go against the grain anyway?

If i had time and money to modify a TT i would ditch the primary turbo for a supercharger and run a setup very similar to the VW 1.4 TSI. Now that would be a interesting challenge with a 2.5L.

Went up for the Dyno-Tune on Monday...With standard exhaust (being the factory dump pipes into the rx liberty cat back system), tmic, wastegates etc etc, the car made 233.5 hp or 171.74kw atw, @ 14.5psi.
With an aftermarket Intercooler, 3" dump pipes into 3-3.5" Single exhaust, after market wastegate/bov and boost controller, we are certain the 225kw atw mark will be achieved. However the AFM was faulty, and a new one was needed, and fuel pump failed. Also found the fuel pressure regulator was not working.

We now have a new '99 STI AFM, 500hp Walbro pump, Replaced the fuel pressure regulator, the Intercooler is on its way, and a new exhaust to be done bby end of next week. Dual stage boost controller and plum back wastegate to be purchased tomorrow, and hopefully in 2 weeks we will know whether or not it is "IMPOSSIBLE" to make 225kw atw with the sequential twin turbo set-up.

Will keep you all posted.

cheers

[ej25tt]

Heres some info!

"The mechanical supercharger compressor, driven at 1.5 times the speed of the crankshaft, mainly operates at low engine speeds from tick-over up to 2,400 revolutions per minute (rpm) to increase low-end torque. At engine speeds just above idle, the belt-driven supercharger provides a boost pressure of 1.2 bars (17.4 psi)**. The turbocharger assumes full effectiveness at middle revs, and the engine map disengages the clutch-controlled supercharger at a maximum upper limit of 3,500 rpm; the supercharger will then be bypassed once the turbocharger spools up and reaches sufficient speed to provide adequate boost in the upper rev-ranges"

** 17.4 PSI!!!!

http://www.youtube.com/watch?v=20qqavckWdw

By the way jim, this is a sick idea. Would love to try this with the diesel boxer...