Best CT26 upgrade trim?

[Akane]

You should take fivebob's upgrade path if you're looking for just a bit more wick.

ECU
Intercooler
Turbo.

In that order.

50 trim is what I recommend with those stock injectors.
and I've ran 13.477 with just end muffler, intake filter, and boost. Yes the CT26 is okay for a bit of fun but it won't put a grin on my face. Although it's got the best spool ever and the power is smooth, I liked how it can get the rear end out with just a blip of the thottle. TD06 = Upgraded CT26 with 50trim spool, but capable of 400hp+

[GTSMR2TURBO]

I've just bought a Ct26 with a 46 trim T04E wheel in it (havent put it in yet) I'm runnin a 3" Mandrel to a 4 1/2" tip on my SW20, have other people found that it run's more boost because it's so free flowing ??? sorry Im a bit of a noob at this !!! also are there any other bit's Im gonna find I need ??? (ie FCD)

[Al]

Depending on your year of car mate, you could have a gen2.5 which has a 16psi fuel cut, if its not, it will have the regular 12.5psi cut.

Theres three ways of removing it. Buy a FCD for stupid amounts of $$$$
Make your own for under $20 with parts from Dicky Smiths. Or what I have done and pulled the BPS hose out (I am the rangi mod king )

Turbosmart, HKS, GReddy all make fcds for the 3s, they are stupidly expensive though

This is the DIY fcd http://toymr2.tripod.com/fcd.html

And finally my special fcd.....well its actually more of a boost cut remover, cos you no longer have one after you pull the hose out. Look in the rear of the engine bay for the diagnostic box, its grey and says diagnostic on it, next to that is the boost pressure sensor, its a yellowy orange colour on top, pull the hose out of the bottom of it, put a screw or bolt in there to block it up and your done. No more boost cut

[anthonym]

Any info appreciated! (Where are Fivebob and Nemesis? )

Busy . And there's not a lot to add here anyway. To answer your question, presuming you've got a GT-4, an intercooler upgrade from what you've already done would be pointless for a CT-26, don't know about the GT-4 but the stock MR2 intercooler is adequate for the stock turbo. This CT-26 is good for about 250hp before it chokes at higher RPM, and upgrading other things will not fix that; you need a bigger turbo. You can upgrade the compressor side of the CT-26 but as others have pointed out this is a (large) compromise. As has already been said The CT20b is a good upgrade for an extra 50-75hp or so if you can find one and live with it's fragile nature. Otherwise you need to replace the whole turbo, to add to what Akane has said, the key to doing this successfully IMO is using the smallest a/r ratio housing and the smallest diameter turbine possible for a given hp goal (common sense which seems to get lost in the lust for Garrett GT turbos). Of these, my experience suggests that the a/r ratio is most critical and needs to be around .61 for good spool up. Without going into convoluted detail this is why the Trust kits spool so well and off the shelf Garrett GT turbos with a/r's >.61 do not.

[anthonym]

You should take fivebob's upgrade path if you're looking for just a bit more wick.

ECU
Intercooler
Turbo.

In that order.

I'm not sure that's fivebob's upgrade path, but for a gen II 3SGTE I would say ECU then turbo then intercooler, bearing in mind you need to do both the ECU and the turbo to get really worthwhile results.

[gtstarped]

[quote="Al"]Depending on your year of car mate, you could have a gen2.5 which has a 16psi fuel cut, if its not, it will have the regular 12.5psi cut.

This is the first I've ever heard about the 2.5. I had a 1993 GenII and couldn't work out why it was letting me boost without cutting me down in flames up a 1 bar. Guess this is why!

Does Toyota quote this anywhere or is it just a sneaky thing they did without mentioning it????

[GTSMR2TURBO]

Theres three ways of removing it. Buy a FCD for stupid amounts of $$$$
Make your own for under $20 with parts from Dicky Smiths. Or what I have done and pulled the BPS hose out (I am the rangi mod king )

The best bit here is that I work at "Dicky Smiths" so It won't cost that much at all cheers for that, My MR2 was assembled in OCT 93 (the last of the gen 2's) so does that mean it's a gen 2 or gen 2.5 ???

[Lanius]

presuming you've got a GT-4

You presume correctly 1990 ST185 (This I presume, means I have a gen 1 3SGTE?)

an intercooler upgrade from what you've already done would be pointless for a CT-26

Even a CT-26 with TO4e compressor? I'm sure you've realised by now I'm still new to the turbo thing. What is it that is referred to as a/r ratio? What are they referring to when talking about the "trim"?

This CT-26 is good for about 250hp before it chokes at higher RPM, and upgrading other things will not fix that; you need a bigger turbo. You can upgrade the compressor side of the CT-26 but as others have pointed out this is a (large) compromise.

The compromise I assume being lag vs higher boost?

As has already been said The CT20b is a good upgrade for an extra 50-75hp or so if you can find one and live with it's fragile nature.

Which cars did the CT20b come from? When you say "fragile nature", is that because they're a ceramic turbo?

Otherwise you need to replace the whole turbo, to add to what Akane has said, the key to doing this successfully IMO is using the smallest a/r ratio housing and the smallest diameter turbine possible for a given hp goal (common sense which seems to get lost in the lust for Garrett GT turbos). Of these, my experience suggests that the a/r ratio is most critical and needs to be around .61 for good spool up

And would you agree with his choice of TD06SH-20G? What kind if hp are those turbo's capable of producing given adequate fueling?

I'm still not 100% clear on why a stand alone ecu would be better than the standard ecu running with the Apexi Super AVCR + SFC Hyper R. As long as the other two computers/controllers are there, wouldn't they be sufficient to provide the fuel maps, boost levels, monitoring etc for an engine to run at peak performance? Is it simply a case of which ecu handles the most inputs etc? More sensors? More flexibility in fuel maps? All of the above?

Thanks heaps for any info you can give ..

[MyXsPtLk]

This I presume, means I have a gen 1 3SGTE?

Gen 2, gen 1 came in the 165, with the smaller wta intercooler

[anthonym]

Even a CT-26 with TO4e compressor?

I'd say so yes

I'm sure you've realised by now I'm still new to the turbo thing. What is it that is referred to as a/r ratio? What are they referring to when talking about the "trim"?

a/r ratio is a measure of the size of the housing, basically a smaller a/r gives less overall flow but better spool up. Trim refers to the relative size of the minor (the size of the inlet) and major diameters of the compessor wheel.

The compromise I assume being lag vs higher boost?

No, from what I can tell the CT-26 turbine housing a/r is too small to support the upgrade and the exhaust side chokes.

Which cars did the CT20b come from? When you say "fragile nature", is that because they're a ceramic turbo?

ST205 and SW20 version 3 4 and 5 (93-10 on). They are fragile because they have a very thin shaft and use a small ceramic turbine and (relatively) large compressor (increasing the stress on the shaft). For some reason they tend to feed ceramic shards into the engine when they break, which is very expensive.

And would you agree with his choice of TD06SH-20G? What kind if hp are those turbo's capable of producing given adequate fueling?

Yep, with an 8cm2 turbine housing, it's a fantastic turbo. And I agree, you can't beat the Trust kit on value for money at current exchange rates, never underestimate the value of a well engineered bolt on solution . Max hp is about 400, realistically 320-350.

I'm still not 100% clear on why a stand alone ecu would be better than the standard ecu running with the Apexi Super AVCR + SFC Hyper R. As long as the other two computers/controllers are there, wouldn't they be sufficient to provide the fuel maps, boost levels, monitoring etc for an engine to run at peak performance? Is it simply a case of which ecu handles the most inputs etc? More sensors? More flexibility in fuel maps? All of the above?

Fuel isn't really the issue, properly programmed ignition timing to match the torque curve of the turbo is the key, especially for the Gt-4 which seem to load up (and pop) the engine more than the MR2. A replacement ECU also gets rid of the AFM, which IMO is one of the most common (electronic) problem areas on the early engine.

[Akane]

They are fragile because they have a very thin shaft and use a small ceramic turbine and (relatively) large compressor (increasing the stress on the shaft). For some reason they tend to feed ceramic shards into the engine when they break, which is very expensive.

[Lanius]

Awesome stuff Nemesis, thank you very much for the info!

This is all starting to make a lot more sense now. Correct me if I'm wrong, but does this mean that having a larger trim leads to higher boost, with more lag? (I think I understand the A/R ratio now ... more flow = more power to spin the compressor, yes?)

How easy would it be to modify a CT20b with a steel shaft and turbine? Would the gains be worth paying the money to get this done? I gather its quite hard to find a CT20b in good condition these days ... ? I would prefer to keep as much ceramics out of my engine as possible

Regarding the AFM ... I was recently told (in another overseas forum), that the 3SGTE has an AFM, and a MAP sensor? At the time I thought this was complete bollocks, but the person who mentioned it seemed to know a lot about the engine etc.

I haven't put that much serious thought into an ECU for the car yet (having just owned it for over a month), and I'm not keen to spend more than another 3 or 4k on the car in the next couple of years (other than maintenance). I'm guessing the intelligent thing to do would be ECU first, and THEN consider a turbo upgrade? ECU wise, the only thing I ever hear is Link, Link Plus, or Motec.

Is the Motec really that much superior to the Link series to warrant the extra cost? As I'm not planning on using the car as a track or drag car (daily driver), would it even be worth getting the Motec? I've been told there aren't exactly a surplus of people in NZ qualified to tune a Motec properly anyway ... ?

Cheers guys

[Twolitre]

Awesome stuff Nemesis, thank you very much for the info!

This is all starting to make a lot more sense now. Correct me if I'm wrong, but does this mean that having a larger trim leads to higher boost, with more lag? (I think I understand the A/R ratio now ... more flow = more power to spin the compressor, yes?)

How easy would it be to modify a CT20b with a steel shaft and turbine? Would the gains be worth paying the money to get this done? I gather its quite hard to find a CT20b in good condition these days ... ? I would prefer to keep as much ceramics out of my engine as possible

Regarding the AFM ... I was recently told (in another overseas forum), that the 3SGTE has an AFM, and a MAP sensor? At the time I thought this was complete bollocks, but the person who mentioned it seemed to know a lot about the engine etc.

I haven't put that much serious thought into an ECU for the car yet (having just owned it for over a month), and I'm not keen to spend more than another 3 or 4k on the car in the next couple of years (other than maintenance). I'm guessing the intelligent thing to do would be ECU first, and THEN consider a turbo upgrade? ECU wise, the only thing I ever hear is Link, Link Plus, or Motec.

Is the Motec really that much superior to the Link series to warrant the extra cost? As I'm not planning on using the car as a track or drag car (daily driver), would it even be worth getting the Motec? I've been told there aren't exactly a surplus of people in NZ qualified to tune a Motec properly anyway ... ?

Cheers guys

Yes ST185's do have an AFM and a Map sensor, the Map sensor is there mainly for the stock boost gauge which is useless and to initiate the boost cut, look for it on the firewall near the ignitor.
You cannot rebuild ceramic CT20b's due to the fact there is no after market parts available for them unlike the CT26's so you would either have to find a low K's ceramic model, leave it as it is and not put too much boost through it or pray that you could find a steel one off a GroupA ST205, I found one a year ago for a good price but then again the cost of the CT20b plus any rebuild/upgrade costs would not warrent buying one over what you have already got, considering you sound quite happy with it from a previous post in this thread.
Your budget will not leave you with enough money for an aftermarket ecu as well as maintenance but have you already got as much out of your current setup as possible? Do you have an aftermarket downpipe or just a stock gutted cat? A mild camshaft upgrade might be something well worth looking into as well. There is a lot more on a car to think about spending money on besides the engine such as brakes, suspension, a good alarm system and even looks etc that you should also consider.
As far as the aspect ratio of a turbochargers turbine housing goes, the larger the number the more power the turbocharger will produce but this figure is usually determined by the engines capacity in regards to turbo selection because if you put a turbo onto your 3SGTE with an A/R of 1.01 it is going to come onto boost much slower than a turbo with an a/r of 0.63 or 0.42 in the CT26's case. In regards to your question you're not quite right, a larger a/r creates less back pressure in the exhaust housing enabling the turbine to work more efficiently and hence create more power.

[Lanius]

Excellent, thanks for clearing that up dude
If anyone had tried to tell me they had AFM as well as a MAP sensor I would have called them a liar You learn something every day!
Would I be correct in assuming that the MAP sensor cannot be used to replace the AFM if the stock boost gauge isn't being used?

Yep, I'm pretty happy with what I've got for now, as I'm still "learning the car". I've been driving quick (not fast ;P) fwd's for about 4 or 5 years now, and this is the first decently powered car I've owned (not to mention 4WD). Once I've learnt the car and how it reacts etc, then I'll consider getting into the power upgrades. First thing I'm definitely spending cash on is the suspension (been eyeing up a "whiteline" package). Brakes are already done

I've been thinking about other things that can be done for mild improvements at a manageable cost, as (like I said) I'm not after a monster traffic light grand prix machine or anything

Can anyone give me an idea as to what kind of results cam grinding would produce on this kind of set up? All I know with cam grinding in a turbo system, as that you can't run as aggressive a profile on a turbo'd engine as you can on either NA or supercharged.

In the mean time, I'm still looking for an improvement in intercooler. Once the intercoolers been sorted I'll look at putting some dollars aside for an ECU. I think I've got all the main parts I need for now, so will look to get something that will hold it all together nicely

Thanks again for your help

[Twolitre]

Would I be correct in assuming that the MAP sensor cannot be used to replace the AFM if the stock boost gauge isn't being used?

The only way you'd be able to ditch the AFM is to replace the ecu with an aftermarket item or rewire an ST205 ecu with ST205 injectors and sensors.
The whiteline kit is quite pricey, mainly because of the Konis, try what i'll be doing and source local shocks and springs but purchase the whiteline rear swaybar which apparently makes a huge difference and replace the suspension bushes with urethane.
As for information about camshaft upgrades, have a look at the link below and then click on the "latest dyno results" at the bottom of the page for a relative guide between engine mods.
http://member.newsguy.com/~gtfour/

[Lanius]

Yeh, I've heard the same about the Whiteline's (shocks and springs too soft), but I'm not sure if you can get the parts individually in NZ? If so, do you know which retailer / wholesaler would stock them?

I've already got urethane bushes all round (including rear diff mounts), so it'll just be the sway bars I wanna get done. Also looking at replacing the strut braces (which I think the whiteline package also provides).

[Twolitre]

https://www.whiteline.com.au/store/

Just enter '"st185" under keywords and it brings up all their products and apparently you can order online over the website but they also list SAS as a NZ distributor so it might be worth poping in to see them, let me know if you're keen as I'll be ordering a rear swaybar too.

SAS Auckland (was Shock Absorbers Services)
611 Great South Road
Manukau City
Auckland NZ
Ph: 64 9 2623684
Fax: 64 9 2623683

[Lanius]

Awesome! Thats exactly what I was after!! Thanks heaps Twolitre
Have to wait a couple of paydays, but I'll definitely let ya know when I'm planning on going ahead with the purchase