Turbo sizing for 4agze to 4agte conversion

[beeker]

I've made the call to Turbo the 4agze in the AE86. As its a Targa competition car, i'll probably buy a new turbo so its nice and reliable. Remember Targa has lots of on/off throttle and your guessing the whole time about whats comin up around the corner, thens bursts of speed and then on/off throttle again.

The wants:
> I want Lots of torque
> Quick to Spool, a must
> Minimal lag, a must
> Good throttle response

250hp is acceptabe

Someone has suggested a T25g. Along similar lines I'm thinking a mid to small garrett ball bearing, but i'm not really up with specifics here.

What would be recommended ? Also what about wastegates ? Internal/external, size ?

thx in advance.

[bluemaumau]

t25 sounds good but i thought they werent ball bearing?

(off a ca18)

[Stu-]

TD05h. Stupidly reliable and make really usable power.

[Steve123]

GT28R or RS 0.64A/R

[beeker]

GT28R or RS 0.64A/R

Somone told me that the T28 would be too laggy for an on/off throttle style of driving ?

[Steve123]

Should be ok as long as you keep the revs up. If you fit a smaller turbo you'll need more boost. GT2554R is next size down and is only rated at 240hp.

You could also try a VF24 or similar. PITA to fit though

[Caveman]

Tha Shz is using a GT25R. ball bearing garrett turbo, rated to 280HP (or 250HP, cant remember). Should be right up your alley. Ralatively cheap too.

td05 might be a little big for 4age and targa. So would vf22 STI turbos.

Im using a vf8, rated to 270HP but I imagine a little lagier than the GT25R. They use a pretty big ex housing (same as the STI turbos) but as a trade off have really good top end

[Caveman]

Should be ok as long as you keep the revs up. If you fit a smaller turbo you'll need more boost. GT2554R is next size down and is only rated at 240hp.

You could also try a VF24 or similar. PITA to fit though

Oh 240HP for the gt25r. There you go

[crnkin]

Did we pop round to your house and drop the gearbox off?

From what you were saying, about targa being alot of 2nd and 3rd gear, im thinking you are quite high in the revs.

When your racing, your always up in high revs, so the spool up time is not so much of an issue. Its like a drag racer saying "dur i wanna small turbo for wicked spool up" when your only spooling up for like .5 seconds (if not running antilag)

Two examples of turbos:

My 4agte runs a vf10. Hits 7psi (full boost) by 3400 ish on a bad day and then pulls VERY hard all the way to 8k.

My friends 4agte runs a m10 t25 (what your suggesting). Hits full boost by bout 2800ish, very fast spool before then, but reaaaaaaally runs out of juice in the higher revs, the spool is noticably quicker, but the car is noticably slower overall. (he does have poos gear ratios but still)

Now aiming for 250hp is sweet. You can get that kind of power very very easily on stock 4agze engine with a turbo. Your probably looking at 10psi boost on a BB t25 to hit 250hp. but can safely run 15, so id be up around there, at around about 280hp at the fly.

Remember there are lots of trims in the t25, and lots of varying qualities of them too, Some are rooted and some are like new.

If I were you id probly be looking at a BB t25, a vf8/10, or a t28 from s14/5 with the smaller ex wheel.

One thing I can tell you for sure is, your gonna love the 4agte, and NEVER turn back

[strx7]

a key thing to remember is that for an application like targa, when you can see stages of upto 40km, too smaller turbo will start to harm your engine due to it not being able to expell exhuast heat. If you're not affraid of spending the $$ for the right set up then ball bearing is the way to go

[matt dunn]

I have had a few turbo setup on my 20V turbo circuit car,

and after running a couple of T28's and Hybrids, and spending a lot of money, I wish i had just gone and bought a new BB Turbo.

Matt

[beeker]

a key thing to remember is that for an application like targa, when you can see stages of upto 40km, too smaller turbo will start to harm your engine due to it not being able to expell exhuast heat. If you're not affraid of spending the $$ for the right set up then ball bearing is the way to go

What model would you recommend ?

[beeker]

I have had a few turbo setup on my 20V turbo circuit car,

and after running a couple of T28's and Hybrids, and spending a lot of money, I wish i had just gone and bought a new BB Turbo.

Matt

bb = ball bearing ?

[beeker]

Did we pop round to your house and drop the gearbox off?

haha, small world.

So what about wastegates ? internal ? external ? size ?

[flygt4]

You could also try a VF24 or similar. PITA to fit though

i run a vf24 , i would use something else if i was doing it from scratch. makes decent power tho, 250hp is a breeze. boost is a bit slow to build tho , in the low to mid 4000's for full boost , but i also have a bit lower compression than standard.

id say get yourself a nice new internally gated ball bearing jobbie in approx t25 sized trim , maybe slightly larger.

[strx7]

I'd also look at running W.I especially on the longer stages, what EFI system are you running? are you running something that can trigger an auxilary feature based on intake temperature?

[matt dunn]

bb = ball bearing ?

Yes.

[Crucible]

I just finished building my GTE, has a .70 a/r exhaust and I dont see full boost till about 4-5k, boost gradually builds then Whammo , yah Gotta love the top end pull on the big T3/4's, but then again I built for topend power!

[crnkin]

If youve got the money, which i 'think' you do, id go straight to garret, maybe www.cheapturbo.com, and buy a gt28bb series turbo. Supposedly the GT2871RS bb turbo, by garret, provides the best possible a/r's for spool and power on a 4agze, theres a couple of people in the USA who recommended this turbo to me, and at 25psi its good for 400hp atw, with full boost before 4g. Only problem for me is i make 20 bucks a decade and the turbo is about 1700 dollars.

Internal wastegates are fine, externals sound cool and flow alot of gasses but most new bb turbos are up around the 35-38mm mark for their internals anyways, so no need for external.

Nice audi

[crnkin]

http://cheapturbo.stores.yahoo.net/gt2871r1.html

or

http://cheapturbo.stores.yahoo.net/gtdpo.html