Stock 4AGE Smallport Turbo Choice please

[rick q]

I’m currently running a Silvertop / mild cams / Haltech in my clubman [127hp ATW] but am toying with going for a mild turbo alternative just for shits and giggles. I’m not looking for anything huge as far as power goes, but it must be a controllable and linear power delivery, as the clubbie sees a lot of track days.

I currently have a spare Smallport [genuine 80K, stock and in very good nick] which I’d like to use – leaving it totally stock [standard pistons, compression, cams, rods etc] for a budget build. The engine will be freshened up, but the only change I’m anticipating is ARP rod bolts.

I’m imagining a maximum of 7-8lbs boost with a rev peak of around 7500 to suit the current gearing.

I already have a TD04 in good condition, but a couple of my sons are saying I’d be better with a Garret T25.

As an oldie, I have no idea, but seek the combined wisdom of those on the forum who know.

Thanks in advance ………..

[trdee]

You can run 7-8psi fairly easily without much trouble as long as it has a good tune. However if you are going to pull the engine apart to install rod bolts, a set of factory forged GZE pistons are like $57 each (or something equally stupidly cheap like that) and will cope with whatever you throw at it. Food for thought.

[feral4mr2]

indeed, chucking a set of 8.9:1 4agze slugs in will be cheap insurance in case you decide to turn up the wick later on. like above, tuning can help you boost nearly any engine and c/r. you could always use a TRD 0.5mm or 0.8mm headgasket to raise the c/r a smidge if you went with the gze pistons.

I'm a Garret fan, the little GT2554r is a mint turbo on these engines for lower boost applications.

[JustenGT8]

This thread is relevant to my needs

[jondee86]

I already have a TD04 in good condition, but a couple of my sons are saying I’d be better with a Garret T25.

Yes... I researched this quite extensively when considering putting a turbo on a 16V smallport, and the general concensus from those who know is that the TD04 is not a good choice. Before I changed tack and decided to go with a supercharger, I was looking at either the GT2554R or GT2854R.

Cheers... jondee86

[knightrous]

Yes... I researched this quite extensively when considering putting a turbo on a 16V smallport, and the general concensus from those who know is that the TD04 is not a good choice.

Any evidentual reasoning behind that?
I ask because I'm looking to drop a TD04 on my 4AGZE AW11 (to replace the relic SC12) and all the research I have done shows good results (140-160RWKW) with when used on 1.5-1.6L motors.

[maj]

TD04's are fine for small engines. Sure you can get better turbos, but the TD04 price vs performance, you aren't going to find anything better for cheap. $50 finds you an ex WRX turbo with still a lot of life left in it. I've personally owned a twinscroll TD04 that plugged along for 280,000km untouched and never gave me any hint of issue. Was factory installed.

TD04's usually start to boogie about 10psi, anything below that is still fine, just look at getting one with smaller housings so you can make best use of your spool time.

I also agree with the consensus that if you are pulling apart the engine to refresh it, you might as well drop in GZE slugs and wind up the boost on a TD04 to 15psi. An untouched smallport 4AG should be fine if you limit boost to around 8psi.

[old_mr2]

I am running a 2560r with great results.

7-8 PSI would be great in a clubman, but I do worry that you will want more boost after only a short while.

[trdee]

This thread is relevant to my needs

Since when did you have a turbo 4A???? If you want specific info on stuff feel free to PM me. I have quite a bit of experience in this field now

performance wise - i would pick a TD04 over a T25 any day. They are newer, cheaper, more commonplace (nowadays), spool better, and are generally much better suited to a low boost 4A application. Most used T25s are flogged out pieces of shit, and they are based on 30 year old turbo tech.

If you have dollars to spend - then one of the new range ball bearing billet wheel jobbies from garrett/borgwarner etc would be ideal, but realistically they don't provide significant benefits unless you are chasing decent boost.

[maj]

Since when did you have a turbo 4A???? If you want specific info on stuff feel free to PM me. I have quite a bit of experience in this field now

I don't recall the Zulu having an engine, I guess the cats out of the bag now?

[trdee]

Just checked, ZZR1100 engine

[maj]

Oh, then the KE10/15/20 he has? I have no idea.

[rick q]

Great information and advice so far - thankyou.

The reason I was keen to stay with the standard higher compression was to increase response for track use, even at the expense of peak power. I've seen a few clubbies with big power turbos and they seem to have a lot of strife in the transition between "I'm just a low compression 1600" to "I've got full boost now" - mostly spinning off in the process. At my age, I have neither the skills or reactions to deal with that

..... and if it does grenade, I can just go back to the Silvertop.

I apprecite that the ZE pistons are cheap - it may be worth going that route but bumping the compression up to maybe high 9's to keep the response sharper


Keep the advice coming, fellas.

[trdee]

The AE101 GZE pistons are 8.9:1 comp. Combine them along with a TRD head gasket and you will easily get into the 9s.

With a TD04 or similar sized turbo, you will be making usable power from 2000rpm. You will need to change your driving style to suit the response of the turbo, that is simply a fact of life, but it shouldn't be difficult to drive in any way.

[jondee86]

Any evidentual reasoning behind that?
I ask because I'm looking to drop a TD04 on my 4AGZE AW11 (to replace the relic SC12) and all the research I have done shows good results (140-160RWKW) with when used on 1.5-1.6L motors.

I was looking for something that would spool up early and make 6-8psi with a reasonably flat torque curve. A new genuine Garrett GT2554R is a quality water and oil cooled ball bearing turbo with an internal wastegate, and the indications were that it would do a good job for what I wanted.

If I was looking to have a big top end with 15-20psi on a GZE, then I would be looking for a larger turbo, and a TD04 would be in the reckoning. Just a question of trying to find the best turbo match for the end result you have in mind

Cheers... jondee86