Best CT26 upgrade trim?

[MyXsPtLk]

Hey there I have a friend in the states who's sending me a steel shaft from a usdm ct26, and a bigger compressor wheel, got a few questions.

Will the steel shaft fit directly into my current turbo? Or will I need him to send me the entire turbo?

Also, what will be a good trim for the new compressor wheel. I've heard 46, 50, 54 but my friend recommends a 60-1 trim which I think is huge, but he says he's tried a 46 trim and there wasn't that much improvement and a 54 trim had a lot of "flat spots" (I have no idea what he meant by that). He's not sure how a 50 trim would be like but he says he's had the best results with a 60-1 trim, a bit more lag but a whole lot more oomph. How much more lag do you think there will be? Also, will I be able to use this with my stock ecu?

I don't want anything too hardcore, I'm just gonna do the intake and exhaust. I want something that is better than normal, but not to the point where I have to start spending heaps on fueling and/or a new ecu. Will a fuel pressure regulator help? I don't plan on changing injectors or fuel pump, but I will if I have to.

So based on all that, what would be the best trim? And what are your thoughts on the 60-1 trim? A bit too much for me?

Oh yea how much would all this cost anyway? A rough estimate, since I'm supplying my own compressor, to rebuild the turbo, new bearings and seals and everything, fit the new compressor, machine the housing to suit and maybe port the wastegate (I only heard that's good, what's so good about it?)

Thanks all, any little bit of info is appreciated.

[Dell'Orto]

Trim depends where you measure it from I believe...but if they mean .60 trim in the usual usage of it, thats a big mofo compressor, and you'll need to backcut the impeller wheel to get it to make any power, it wont be able to push enough exhaust energy through it to get any high rpm action otherwise. It will be quite a bit laggier than the standard one, but thems the breaks.
I've been told there isnt much point porting the wastegates on CT26's, as the twin poppet wastegate is quite sufficient (even though mine was ported, I'm not 100% sure why they did it)
Yes the steel wheel will fit in your turbo, and depending where you get it done, it'd be between $550 and $900 to do...just had mine done by Steve Murch, and with him supplying the wheel it was $920+. Stock ECU shouldnt have a problem running it, though you will need a FCD to make use of it, and it you want to push the boost you'll want to get a FPR as well as upgrade the oilcooler, sorry interwarmer

[MrBob]

Trim depends where you measure it from I believe...but if they mean .60 trim in the usual usage of it, thats a big mofo compressor

he means 60mm trim as in the compressor wheel daimeter (largest diameter), not the a/r of the housing (ie, .6)

I have a 57mil wheel in mine with machined out housing. goes fine for what it is, but dont expect particulary staggering results.

[MrBob]

I've been told there isnt much point porting the wastegates on CT26's, as the twin poppet wastegate is quite sufficient (even though mine was ported, I'm not 100% sure why they did it)

just noticed this second point.. it would be a good idea to get the wastegate machined out...or just run a small external. The standard wastegate is NOT SUFFICIENT as is evident by the fairly etreme boost creep that occurs when you fit a decent unrestrictive exhaust (on an sw20) if its on a gt4 the creep is pretty minimal.

generally speaking, upgrading a ct26 is a fairly pointless exercise, and its money better spent elsewhere..

[Dell'Orto]

I've been told there isnt much point porting the wastegates on CT26's, as the twin poppet wastegate is quite sufficient (even though mine was ported, I'm not 100% sure why they did it)

just noticed this second point.. it would be a good idea to get the wastegate machined out...or just run a small external. The standard wastegate is NOT SUFFICIENT as is evident by the fairly etreme boost creep that occurs when you fit a decent unrestrictive exhaust (on an sw20) if its on a gt4 the creep is pretty minimal.

generally speaking, upgrading a ct26 is a fairly pointless exercise, and its money better spent elsewhere..

Hmm, its strange I got conflicting advice on this...the performance place that did my turbo said it needed doing as it was creeping badly (I do have a 3" exhaust off the cat, 2 mufflers) yet when I rang them a couple of years after it being done they said it wasnt necessary at all. Odd.

For the money it costs, I dont think there would be much better option, particularly when all the other bolt ons are done.

[Al]

go ct20b

the results speak for themselves

[Dell'Orto]

Find me a CT20B for less than $900, and I'll buy it

[MyXsPtLk]

hrrrmmmmm.... okay so a ct26 isn't worth doing. What if I decided to just throw in a t3/t4 turbo into it? Just a theoretical question!! I know it takes some custom work, probably need a new manifold, custom oil lines etc but lets say I have JUST enough money to get a t3/t4 fitted into my car properly (185 gt4), would it be safe to use on my stock ecu and fuel setup? I was thinking one of those stage 3 turbine, .63 a/r, 46 or 50 trim compressor, which one would you guys recommend out of these 2? mmmm... pretend money...

[Akane]

Upgrading the CT26 is not too bad if you want to keep it stock. But if you want to run with the big boys, you have to upgrade with a bolt on turbo. Don't go with that t3/t4 crap, the word "T3/T4" is over abused.

"Hey I have a phat turbo, it's called T3/T4, god knows how much power it really makes, but it's a T3/T4, it's ownage!"

:rolleyes:

If you want a bolt on turbo, the best kit is the Trust TD06SH-20G, great balance between lag and power, that'll let you run with the big boys.

Expect $3k for such a kit.

And the 54 trim is very popular amongst americans, also the 50 trim. but amazingly, 50 trim makes more power.

[MrBob]

Hmm, its strange I got conflicting advice on this...the performance place that did my turbo said it needed doing as it was creeping badly (I do have a 3" exhaust off the cat, 2 mufflers) yet when I rang them a couple of years after it being done they said it wasnt necessary at all. Odd.

I was speaking from experience, not advice. With a 3" straight through exhaust I got boostcreep up to 16psi from 5000 - 7000 rpm. My rebuild was around 850 with w/g machined... but that was a long time ago.

MyXsPtLK:

If you decide to run an aftermarket turbo, just get an adapter plate made for the standard manifold. Standard manifold has been prooven to be adequate to around 500hp.

[Lanius]

My st185 has a CT26 with TO4e compressor, and ported wastegate (or so I'm told by the person I bought the car from ), and it stonks along on between 12psi and 16psi quite happily (couple of other bits and pieces with it to keep it happy there as well). Apparently this set up is quite popular with CT26's?

Its pretty laggy (only comes on hard around the 4500rpm mark), and I'm pretty keen to get the kick a little bit lower, without losing the power at the top end.

Akane, is that $3k for the Trust TD06SH-20G purchased and installed, or just purchased?

[Twolitre]

Due to the strong NZ dollar you can purchase a Greddy TD06SH Turbo Upgrade Kit for just over NZ$2k but freight would probably be a couple hundred dollars from the US but apparently the build quality of some of the components in this kit is questionable.
An upgraded CT26 is capable of high 12's in an ST185 so if that's all you want then it will be your cheapest option but with a FMIC it will be a bit laggy that's why I have chosen to go water-air.
If you really want to get serious I'd reccomend a Garret Ballbearing turbo, have a look at the site in the link below, they have a good range and good prices.http://www.atpturbo.com/Merchant2/merchant.mvc?Screen=CTGY&Store_Code=tp&Category_Code=GRT

[Lanius]

High 12's on stock internals? I'm still pretty new to 3SGTE's ... what kind of punishment do their stock internals handle? Already got FPR, FCD and boost controller. I'm assuming 1.0 to 1.25 bar should be safe for a 1990 GTE?

And yeh ... I thought the fmic might be adding to the lag a fair bit.

Would it be worth considering a TD05 (WRX RA turbo if I'm not mistaken) for a GT Four? Assuming that it would spool a bit faster given its a smaller turbo?

[gtstarped]

I have a write up from a NZPC car mag which quotes the following flow:

T04E 46trim 50.8mm 375bhp 37IB/Hr
50trim 53.9mm 440bhp 44IB/hr
57trim 56.6mm 450bhp 45IB/hr

From this I would say that a 50trim would be the best due to the flow and the fact that it would spoil faster.

We have a 50trim which wasn't my first choice but I'm sold on it now. Goes alright but you don't get much advantage till you get over 16psi as the T04E is for high boost compressor where a T04B is for low boost.

We are running 17-18psi and we are detonating. Had to get a FPR, just need to get it tuned now.

[Al]

High 12's on stock internals?

With a massive 1 bar boost on my ct20b i trap 108-109mph (174-175km/h) Thats well into high 12s territory, I'll be back on a prepped track this time with a bit more experience and hit 12s. Stock internals, stock fuel, stock intercooler....

[MyXsPtLk]

T04E is for high boost compressor where a T04B is for low boost.

So does that mean that a T04B 50 trim would suit my car better? I haven't bought the wheel yet because I can't decide what is better.

[gtstarped]

Don't quote me on that as thats what the NZPC says, I've heard that the B version is a really old compressor and is quiet primative. But then so is the E.

I would ring Alltech on Wairau Rd, Glenfield and find out what would be best suited to your application. Tell them what you want out of it and how much boost you will run.

In all the American and UK turbo upgrade they only really go up to 46 or 50trim. Fensport for example go to 48mm in all of there 4 upgrades whether you want to spend $1500 and $2200. Have a look at there upgrades here:

http://www.fensport.co.uk/products.htm

Heres some more info on the CT26. Excellent write up.

http://www.mrcontrols.com/primers/turbo.htm

From what I have heard, the CT26's problem is the flow out of the turbine not the airflow through the compressor. For every size upgrade you can get 46,48,50,52,57,60 the gains are probably less with each size bigger.

If you are going on run up to 1 bar on a standard ATA intercooler I would probably just go for either a ceramic CT20B which is 47mm which has quiet an aggressive compressor shape and will pull you back hard from lower down or a 50trim T04E. Might want to keep the boost down in hot conditions with either though with the shit ATA.

[Akane]

Lanius, installation ain't all that hard, since it's a kit and everything will bolt right on, a tad under $3k is about right since the NZ dollar is crazy strong now. back in the days $3k will get you just the kit.

I have used both Trust TD06SH-20G, and now using the Garrett GT ballistic concepts GT2540R, sorry but the TD06SH gives the same amount of power, and nearly 1000rpm faster spool (0.85bar).

This is due to the design of TD06SH-20G.

[Lanius]

Sweet. Well, I'm not looking at trying to break any records with my car at this stage, so I'll stick with the CT26 I've got and see what I can do with it.

Will probably just look at improving what its currently running (more efficient intercooler, better boost controller, possibly upgrade fuel pump and injectors).

Now on the point of intercoolers ... I've currently got a VR4 intercooler front mounted. Having had a look at the front of the car, theres a bit of room left to work with, so I'm keen to get something to replace it. I don't want a wopping-giant-chromed-stick-out-of-the-bonnet-and-blind-low-flying-aircraft intercooler, just something more efficient than what I have atm.

Would I be correct in assuming that an intercooler with the same dimensions but with a thicker core, will straight away be more efficient? Does a thicker core mean more lag when coming on boost? (I would assume so as there is more air to move through the system).

I don't really want to go custom, as I'm not rolling in disposable income (yet ), so can anyone recommend a reliable ata intercooler with good heat transfer, roughly the same dimensions as a VR4 intercooler (197mm x 415mm x 65mm)?

How easy is it to get a wta set up going with a front mount?
Any info appreciated! (Where are Fivebob and Nemesis? )

PS: Sorry for hijacking your thread MyXsPtLk!

[gtstarped]

Theres plenty of power to be found in a ST185 CT26 40mm compressor, I did a 13.9 in my old thin body ST185 with just a standard ceramic CT26, 1.1 bar, 2.75 inch exhaust from the cat and a cat replacement pipe but with standard elbow.

The standard steel twin entry CT26 has a a 43-44mm compressor but has no bottom end torque compared to the 40mm due to the shape of the blades. The 40mm gives up much faster though, around about 6000rpm-6500rpm. Kind of like the difference between driving a GSR and EVO.

GSR's & the 40mm compressor GT4's are much better as a daily drivers cause you always have the torque.

RC's and other GT4's with the steel turbines build power and never really give you a good kick up the arse.