[Mk2] [Turbo] Ct fitment hybrids?

[Ryan S]

Looking at a bolt on turbo whats available? S148 looks great but hearing conflicting info on how it spools. Basically I want the car to drive more or less like stock but with some extra oomph. On paper the s148 looks fantastic.

Any other options?

Feel free to air your thoughts and experience.

[SonicSW20]

Turbos like the S148 spool a little later than a stock CT20B, but are capable of more up top.

If the objective is to get both more up top, and a better power curve overall, then really the only way to do it is with a good aftermarket small frame turbo designed to do just that. GTX28 series for example.

Nixspeed in the US do a custom exhaust housing for a GTX28 that makes it direct bolt in fitment to a 3SGTE.



"Here is the dyno results from the CTX28 bolt up turbo upgrade. The solid line is the CTX28 and the dashed line is a billet ct20. They were both tested at 19psi. The ct20 did climb to 20psi at the end but fairly close.
Keep in mind this test is done at 5500ft of elevation which causes a lot of flow and hp issues but these are corrected numbers on the graph and both corrected and uncorrected in the other pic.
The instant spool and huge tq increase is definitely noticeable on the ball bearing CTX28. Unfortunately the gtx2867 gen2 is a higher pressure ratio wheel and needs to be above the 19psi to really come alive. This is at the very bottom of the compressor map as far as efficiency. This test was done on a bone stock 3rd gen with stock ecu and fuel. It was off the scale rich as soon as it got into boost. We are getting a different turbo that will fit the stock ecu and lower pressure ratios and will post those results. "

"cheapest" way to get that setup in the US is get the housing only and source a super core locally: https://www.nixspeedracing.com/shop-mki ... 28-housing

But whichever way you cut it, it won't be cheap! Probably 50USD or more in shipping to the UK, and 20-25% tax on top. Call it 500USD shipped for the unit so you're probably looking at around £470 to your door for the housing only, plus a grand or so for a GTX2867R Gen II Super Core, and you'll need an actuator.

[Ryan S]

Somebody on faceache showed me this, it's way to expensive. My goal is just drivability. Jaaaaaaaash on here says his GTX28 is a bit laggy. I gues the only way to have an mr2 actually drive like an mr2 is to have it stock with bolt ons

My goal really is drivability though. It's all well being able to keep up with a Ferrari but if I wanna overtake on the motorway it's not so much fun ha!

I have a wee audi TT as my winter car and it drives soooo nice, Instant spool and it pulls really well at low revs, No dropping gears etc. Foot down and it just goes. It feels like it's around 260-280BHP but I don't know what the power is, Whatever it is I thought it was gonna feel soooo slow compared to the mr2 and it just doesn't. So this has got me thinking about changing turbos. I reckon a GTX28 is the way to go as well.

[SonicSW20]

Which specific variant of the GTX28 did they have? There's loads of possible combinations which will give varying results!

[Ryan S]

Which specific variant of the GTX28 did they have? There's loads of possible combinations which will give varying results!

Not 100% sure to be honest. Spoke to midlands turbo who apparently do a faster spooling version of the s148. Based on a ct20. Can do over 400bhp too. Comes in at £800ish all in.

[SonicSW20]

I'll believe it when its on the car

I have thought about going standalone as I do have an S148, but I do wonder how well its going to last at the pressures / turbine speeds needed to get north of 350bhp. Its still CT bearings, shaft etc and they just don't seem to take that sort of punishment very well at all. GTX Gen2 will do it all day as long as you keep it oiled and watered, but thats one of the reasons it costs twice as much.

[Ryan S]

Good evening Ryan, we do offer repairs and upgrades on customer supplied CT20s yes, but we don't supply them outright.

The are fully rebuilt with steel exhaust turbine wheel, a larger 71mm billet compressor wheel, cutback exhaust turbine blades and uprated bearings and seals. Aswell as all the necessary machine work. We can also supply them with an uprated actuator if necessary. We don't any dyno printouts to hand but we will speak to previous customers and see if we can get one for you.

As for price if your turbocharger is in a good condition it'll be £455+V.A.T with the stock actuator fitted or £535+V.A.T if you wanted the stronger actuator fitting. Obviously if your turbocharger is in a poor condition to begin with then the price will increase dependant on what needs to be replaced.

Kind regards
Midland Turbo


Yeah it's of similar sizes to the S148 however that unit uses a really old T38 compressor wheel and they tend to suffer compressor surge whereas ours uses a much newer billet wheel design.


Kind regards
Midland Turbo

To be honest I just want some drivability again and if that means going down to 300bhp then so be it.

[Ryan S]

How's the spool with the s148?

[SonicSW20]

How's the spool with the s148?

Been over a year since I've driven it anything over actuator pressure / full throttle as a rod bearing shat itself last year and break in isn't done yet, so I can't really remember tbh

The S148 has a totally custom exhaust housing, it actually not a twin scroll housing anymore, and has a single larger wastegate port which gives more flow, so you should never run into that classic 3SGTE boost creep issue with it. I am not sure of the other specs of this housing, thats a question for them I think! Downside of that is you do lose some response right at the low end where that twin scroll really makes a difference. I know of a chap who was running one of these at ~380bhp. I know a dyno chart exists somewhere, but its been a few years. I'll see if I can find it.

With the Midland one, I can't see how a larger compressor and heavier steel turbine would see better low down response?

[SonicSW20]

This is it:



I believe he also had different cams etc so that will affect where it spools etc.

[Ryan S]

Very interesting. At least I have options I guess. 380bhp would be more than enough. I'm at 480bhp just now and it really is just too much ha!

[androo007]

Look @ the newer G25 range

[Ryan S]

Going 2GR turbo now man. Probably just use the turbo I have. A 3.5 litre will spool it extremely quick.

[androo007]

SURELY if you're going down the old school route you'd go semi-modern and twin turbo?

[Ryan S]

I would. But single is much less complicated plus I can get a turbo exhaust right off the shelf. I have it all planned out

Would be cool actually having a twin turbo mr2 mind you

I would say the 2gr is semi modern. It's coil on plug and VVTi. All alloy block (lighter than the 3sgte). Variants of the 2gr are still in use by lexus now. Also the 2gr is whats used in the exige and evora still.