Max power on 3sgte Rev1 /Rev2

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Max power on 3sgte Rev1 /Rev2

Post by Voivod »

What's the maximum power anyone achieved on Rev1 Rev2 3sgte? Stock engine,stock ECU..slightly bigger injectors,hybrid or aftermarket turbo or turbo from other vehicle? Any UK records for that?

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Re: Max power on 3sgte Rev1 /Rev2

Post by MR2DI4 »

You cannot run bigger injectors with the stock ECU. The CT26 is the problem it only makes 10psi at the redline. Sensibly modified with supporting mods on a Dyno that's accurate 250Hp at the wheels.
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Re: Max power on 3sgte Rev1 /Rev2

Post by Voivod »

MR2DI4 wrote: 04/03/21 9:16 You cannot run bigger injectors with the stock ECU. The CT26 is the problem it only makes 10psi at the redline. Sensibly modified with supporting mods on a Dyno that's accurate 250Hp at the wheels.
Why not? Stock injectors are 440cc so if I choose say 480cc just to eliminate running lean at higher boost and I think that stock ECU will coupe with that no problem. I've not mentioned CT26 at all.However it can run more then double what you suggest and according to many data on internet. But I said hybrid or aftermarket turbo or turbo from other vehicle.Sensibly modified with supporting mods it's a grey area until you explain what that mean :laughing

p.s Taking in consideration that I'll be using the most aggressive cam from 3sge :laughing
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Re: Max power on 3sgte Rev1 /Rev2

Post by MR2DI4 »

Do some research there is plenty of information available now as the MR2 is old. I went down the whole path of modifying mine myself back in 2008. The stock ECU doesn't "Cope" with the modifications very well because you cannot tune it properly, arguably you cannot tune it at all. Adding external boxes to it doesn't really count, your just fiddling with it. Essentially your flying pretty blind outside the factory boost parameters. The stock engine runs very rich under boost, that allows you to up the boost to the 15 to 17psi area and then the stock safety is gone. Essentially you start using fuel pressure to control the mixture. If you want decent gains with reliability you move to the later gen engine or do a complete engine rebuild and go aftermarket ECU so you can actually tune the car.

Just doing what I did to mine was a lot of fun but the gains are not huge. I got like 225Hp at the wheels in the end. If I wanted more the top end of the engine would need a rebuild with some port work and the stock exhaust would have to go but its simply not worth the time and effort for me these days, its a law of diminishing returns vs exponential increase in dollars. The big change was putting a CT20b compressor wheel into the CT26 and porting the exhaust manifold. That got me from 9.6psi at the redline to 17psi at the redline. The turbo then quickly outflowed the fuel supply so I boosted the Voltage to the stock fuel pump to 17.5V with an isolated output 5V DC-DC converter sitting on top of the stock 14.6V supply from the alternator. A tidier solution would be just to direct connect the 3.3V version. All great fun but on reflection I was pretty lucky it didn't go bang. All the mods didn't happen all at once and there was a track day in the middle of it in which the car got thrashed.

In the end you also need loads of gauges as well so you can watch everything from AFR to fuel pressure to oil pressure and you need a rebuilt alternator thats putting out a rock solid 14.6 Volts even at idle. There remains not much wiggle room for things to suddenly go outside spec, everything "Factory Fitted" gets maxed out.

Fixed cams are a total compromise regardless. The big gains have come from variable valve exhaust timing and I notice some manufacturers don't even bother with variable inlets, you just run huge boost pressures over 20psi which you have to be running anyway to get the power out of a smaller engine.

If you can do all the work yourself you will never regret the experience, if I had to pay someone else to do all the work I would never have bothered, just buy a different car. These days I'm just looking for something that rolls out of the factory that meets what I want, its an age thing.
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Re: Max power on 3sgte Rev1 /Rev2

Post by Voivod »

MR2DI4 wrote: 05/03/21 17:04 Do some research there is plenty of information available now as the MR2 is old. I went down the whole path of modifying mine myself back in 2008. The stock ECU doesn't "Cope" with the modifications very well because you cannot tune it properly, arguably you cannot tune it at all. Adding external boxes to it doesn't really count, your just fiddling with it. Essentially your flying pretty blind outside the factory boost parameters. The stock engine runs very rich under boost, that allows you to up the boost to the 15 to 17psi area and then the stock safety is gone. Essentially you start using fuel pressure to control the mixture. If you want decent gains with reliability you move to the later gen engine or do a complete engine rebuild and go aftermarket ECU so you can actually tune the car.

Just doing what I did to mine was a lot of fun but the gains are not huge. I got like 225Hp at the wheels in the end. If I wanted more the top end of the engine would need a rebuild with some port work and the stock exhaust would have to go but its simply not worth the time and effort for me these days, its a law of diminishing returns vs exponential increase in dollars. The big change was putting a CT20b compressor wheel into the CT26 and porting the exhaust manifold. That got me from 9.6psi at the redline to 17psi at the redline. The turbo then quickly outflowed the fuel supply so I boosted the Voltage to the stock fuel pump to 17.5V with an isolated output 5V DC-DC converter sitting on top of the stock 14.6V supply from the alternator. A tidier solution would be just to direct connect the 3.3V version. All great fun but on reflection I was pretty lucky it didn't go bang. All the mods didn't happen all at once and there was a track day in the middle of it in which the car got thrashed.

In the end you also need loads of gauges as well so you can watch everything from AFR to fuel pressure to oil pressure and you need a rebuilt alternator thats putting out a rock solid 14.6 Volts even at idle. There remains not much wiggle room for things to suddenly go outside spec, everything "Factory Fitted" gets maxed out.

Fixed cams are a total compromise regardless. The big gains have come from variable valve exhaust timing and I notice some manufacturers don't even bother with variable inlets, you just run huge boost pressures over 20psi which you have to be running anyway to get the power out of a smaller engine.

If you can do all the work yourself you will never regret the experience, if I had to pay someone else to do all the work I would never have bothered, just buy a different car. These days I'm just looking for something that rolls out of the factory that meets what I want, its an age thing.
Yeah I did :laughing However there are too much conflicting information out there..lot's of arguments without proof and to that degree that some folks will Foam at the mouth.

Regarding: porting the exhaust manifold? I wouldn't bother because is not the problem even for 20psi. The main differences between CT26 and CT20 it's not just compressor wheel but exhaust elbow,on Rev1 or Rev2 they are the same,but on Rev3 is better flowing and significantly bigger. Now the problem is..even if you ported your exhaust manifold and replaced CT26 compressor wheel with CT20b compressor wheel then you still stuck with the restriction on the other end. And if you wanted to swap the elbow(logically)..then you can't because the oil filter will be on the way and it's impossible to use it on Rev1 or Rev2 engine.

Exhaust manifold it will be my last worry on any generation of 3sgte..what you need to worrying about it's Inlet manifold,fuel rail and injectors design. Cams will make good improvement too..and I don't think there is a room for variable valve exhaust timing in this case. True pioneers were Honda with VTEC one cam but worked as 3.

p.s My mods so far..bone stock engine in good health,hybrid turbo,and 15psi boost pressure and altered ignition dwell angle. I don't know what power figures it producing but Ford Focus St was blocking my way in 4th gear,Ford Focus RS just can pull away from me,and a few others lol

Thanks for sharing you experience :th:
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Re: Max power on 3sgte Rev1 /Rev2

Post by MR2DI4 »

The problem is there are so many myths about the MR2.

The exhaust manifold is worth port matching, especially the end that meets the turbo, that flange is WAY OUT and I mean way out and it can be ported to match the gasket.

There are gains to be made by allowing you to run LESS boost pressure because you have improved the FLOW. Boost pressure doesn't actually tell you the whole story because you can have 20psi but very poor flow.

I run a 3inch downpipe, the stock cast iron elbow and the CAT is gone in my MR2.

The gains come from a lot of very time consuming engine port and flow work thats all done by hand. If your sticking with the stock ECU.

The head was made in conjunction with Yamaha if I recall but there is a lot of room for improvements if you strip it down and look at it. If I ever took the head off it would be port matched using some thin wall alloy tube as dowels and then match to the gasket. You simply cannot get the alignment with just the studs and great big clearance holes in the manifold.

I recon you could get 250Hp on an accurate Dyno with a minimal of dollars spent. My work probably cost me $1500 all up, what it takes is time. It took me a whole day solid just to do the manifold.

There are no restrictions in the CT26. What you need to fist understand is the CT26 is a BIGGER turbo than the CT20b. Unfortunately for whatever reason the compressor wheel was seriously downgraded in the version for the MR2. The Celica rally version that used the CT26 in the limited production model of 500 units made 16psi STOCK and I actually have a compressor wheel from that turbo in my spare. The inducer and exducer size is like the CT20b but the pitch of the blades is less. The only thing I noticed with my CT20b version compressor wheel is an extra 300rpm in lag.

You will find no end of contradictory stuff out there because for starters how many people have rebuilt their own turbo, let along modified it themselves ? Also the people that are doing it don't want you to have any information because they are making money for it, its their business, they don't want people doing it themselves.

The biggest myth on the MR2 turbo is that the stock intercooler is no good. This one is hilarious if you actually do the road testing on it, you find out very quickly how to improve it.
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Re: Max power on 3sgte Rev1 /Rev2

Post by Voivod »

MR2DI4 wrote: 07/03/21 22:40 The exhaust manifold is worth port matching, especially the end that meets the turbo, that flange is WAY OUT and I mean way out and it can be ported to match the gasket.
I'll check that tomorrow :th:
MR2DI4 wrote: 07/03/21 22:40 I run a 3inch downpipe, the stock cast iron elbow and the CAT is gone in my MR2.
I didn't know that as you've said earlier (the stock exhaust would have to go but its simply not worth the time and effort ) So I assumed that entire exhaust system is stock. But even if you have aftermarket down pipe they far from being perfect or pretty much restrictive as the stock exhaust elbow that bolts to the turbo.
MR2DI4 wrote: 07/03/21 22:40 The head was made in conjunction with Yamaha if I recall but there is a lot of room for improvements if you strip it down and look at it. If I ever took the head off it would be port matched using some thin wall alloy tube as dowels and then match to the gasket. You simply cannot get the alignment with just the studs and great big clearance holes in the manifold.
It would be interesting to see the results :laughing First check stock head for flow and do your port matching and check again just to see if you ever gained something.

MR2DI4 wrote: 07/03/21 22:40 There are no restrictions in the CT26. What you need to fist understand is the CT26 is a BIGGER turbo than the CT20b. Unfortunately for whatever reason the compressor wheel was seriously downgraded in the version for the MR2. The Celica rally version that used the CT26 in the limited production model of 500 units made 16psi STOCK and I actually have a compressor wheel from that turbo in my spare. The inducer and exducer size is like the CT20b but the pitch of the blades is less. The only thing I noticed with my CT20b version compressor wheel is an extra 300rpm in lag.
I never said or mentioned that CT26 is restrictive as a Turbo.What I said was that the exhaust elbow that connects to the turbo is restrictive at some point on Rev1 and Rev2. On Rev3 is much bigger and better flowing...see the picture.But you can't use it on Rev1 or Rev2 because oil filter..you have to move it away aka relocate.
MR2DI4 wrote: 07/03/21 22:40 The biggest myth on the MR2 turbo is that the stock intercooler is no good.
I don't even thinking about to replacing it as is just perfectly fine and good unit.

p.s Inlet manifold,fuel rail,injectors,camshafts and possibly other turbo from other car that I will replace in my next build.
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Re: Max power on 3sgte Rev1 /Rev2

Post by MR2DI4 »

Flow is pretty important, you can make more power at less boost. The gains also come from the turbo not having to work as hard. Essentially the wastegate can open more and hence better flow and lower exhaust manifold back pressure. You can only do so much, the valves themselves are a pretty big restriction. VVT makes a huge difference. My NA Subaru feels like a low boost turbo at 4000rpm when it kicks in

My exhaust is stock, its just the cat gets deleted by a 3inch stainless downpipe with a custom made support bracket. Pretty low resistance from one of these. Personally I don't think it makes a huge difference in power unless your cat was totally clogged up. Main gains are a big weight saving and it makes the engine easier to work on and removes a huge heat mass out of the engine bay and improves airflow into the engine bay.
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Re: Max power on 3sgte Rev1 /Rev2

Post by Voivod »

MR2DI4 wrote: 09/03/21 7:27 Flow is pretty important, you can make more power at less boost. The gains also come from the turbo not having to work as hard. Essentially the wastegate can open more and hence better flow and lower exhaust manifold back pressure. You can only do so much, the valves themselves are a pretty big restriction. VVT makes a huge difference. My NA Subaru feels like a low boost turbo at 4000rpm when it kicks in

My exhaust is stock, its just the cat gets deleted by a 3inch stainless downpipe with a custom made support bracket. Pretty low resistance from one of these. Personally I don't think it makes a huge difference in power unless your cat was totally clogged up. Main gains are a big weight saving and it makes the engine easier to work on and removes a huge heat mass out of the engine bay and improves airflow into the engine bay.
Agree on the flow! Wastegate can open more and hence better flow ? :shocked: Wastegate and boost control valve is working together to achieved desired boost pressure..and if you wastegate opens more when it should then you loose the pressure and the power! The stock valves by no any means Is A Restriction..I don't know where you get that from? And why you keep bringing VVT over and over? That's irrelevant to 3sgte..

So you've got 3inch stainless downpipe that connects to stock restrictive exhaust and as you've said (Pretty low resistance from one of these. Personally I don't think it makes a huge difference in power) I'm confused... :confused1:

Weight savings..just remove the doors,passenger seat,boot lid,bonnet ect :laughing

p.s Majority of aftermarket down pipes are crap and cause problems on Rev1 and Rev2. Here is the pics of when wastegate flap was binding,touching the downpipe flange.
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Re: Max power on 3sgte Rev1 /Rev2

Post by Voivod »

MR2DI4 wrote: 09/03/21 7:27 Essentially the wastegate can open more and hence better flow and lower exhaust manifold back pressure.
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Re: Max power on 3sgte Rev1 /Rev2

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[quote=MR2DI4 post_id=1780

If you can do all the work yourself you will never regret the experience, if I had to pay someone else to do all the work I would never have bothered, just buy a different car. These days I'm just looking for something that rolls out of the factory that meets what I want, its an age thing.
[/quote]

Agreed, it absolutely is age thing!


The money I have spent modding cars over the years is frightening, the money I spend to keep my beloved MR2 on the road is silly if I'm honest. But it's a 90's JDM fast car and to me that era is gone and that saddens me. Maybe that's why I keep doing it...

I'll never sell it now, eventually it will get stripped back to nothing and a nut and bolt rebuild and sit in the garage most of the time I supppose.

It does help to have a superbike to really satisfy that reliability, simplicity and ridiculous speed addiction though. ;)
Well those are my principles, and if you don't like them... I have others.

A child of 5 could understand this! Quick, send for a child of 5!
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Re: Max power on 3sgte Rev1 /Rev2

Post by MR2DI4 »

Yeah my MR2 pretty much sits in the garage now as a collectors car. You can put the Rego on hold over here so it basically costs you nothing each year. Solar panel keeps the battery charged.

My Subaru 3.0R wagon is the daily driver and that will get traded on a new generation Subaru STi at the end of 2022 if the car is anything close to 400Hp. Really cannot find anything else that excites me in a 6 speed manual with AWD for what should be under NZD$80K.

Got a bike as well, for the occasional speed "Fix"
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Re: Max power on 3sgte Rev1 /Rev2

Post by Voivod »

MR2DI4 wrote: 07/03/21 22:40 The problem is there are so many myths about the MR2.

The exhaust manifold is worth port matching, especially the end that meets the turbo, that flange is WAY OUT and I mean way out and it can be ported to match the gasket.
As I've told you earlier it's not worth to port matching exhaust manifold.You actually do no good at all and make thing worse!

p.s It's a Rev3 exhaust manifold and CT20 Turbocharger...I can't find Rev2 stuff as my place is in chaos at the moment.
The twin entry ports on exhaust manifold is about 1.5mm narrower compare to the ports on turbocharger.You need to do some research and find out why some manufactures do this specifically. :laughing
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Re: Max power on 3sgte Rev1 /Rev2

Post by benckj »

Take note from what others have said and apply them to you goals. If you want to build a fast car realise it will sit in the garage for most of its life. Rather than max hp my build was more on responsiveness and driving pleasure. I also bought car to learn about forced induction including engine management so decisions to install high tech turbo and an EMS were high priority. Unlike others my gen3 lives outdoors and is always ready to drive at the flick of the key. Still one of the few cars that can travel 1000km to a track day and make it back again under its own stream. Best part is generally the journey to and fro.
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