MR2 engine swap from NA to turbo

[colj]

Despite being fairly experienced in the world of modding (MKIV Supra's) I am very new to the MR2 scene and so if the questions I am asking seem silly then please allow me some slack and be patient.

I have bought a '97 Rev 4 UK car and am delighted with it but, as normal, the modding bug has come to the fore already and I have now acquired a Rev 2 Turbo car that has accident damage to the NSF quarter. I am as yet unsure as to whether to repair the damage (it is a non recorded accident) or do a swap of bits to make the UK car a turbo model. I am yet to really see the damage (the car has not arrived yet) and so cannot post pics but the likelihood is I will do a transplant rather than repair.

My questions are based on what parts from each car I should be using. Obviously I will want the engine, gearbox, loom, ecu, drive shafts etc but are there any off the UK car that is a better option that what's on the turbo? I have read that the Rev 3 / 4 head is better than the Rev 2 but I am unclear as to if they meant a n NA head can be used or if that was a turbo version?

I am looking to get as close to 300bhp as possible when finished and as such I am thinking of fitting the following: Electronic BC, 3" down pipe, straight through after market exhaust, charge cooler from an ST205 and a new fiat rad. Will that be enough or will other mods be required? Whilst the engine is out, I am going to be changing the cambelt and all fluids but would an upgraded HG also be wise?

Sorry for so many questions but I want to do this right. As for a budget? Well, I am not a rich man but I would welcome all suggestions and then look at costs and the options thereafter. My son and I were looking to do a lot of the work ourselves but in all probability (and due to an illness I have), this will be farmed out to a professional with us supplying parts.

Thanks very much for taking the time to read this and I look forward to hearing your thoughts.

[magpie215]

sell the UK car and the donor buy a revision 3 onwards turbo..... will be cheaper and easier in the long run.

[colj]

magpie215 said:

sell the UK car and the donor buy a revision 3 onwards turbo..... will be cheaper and easier in the long run.

I can see where you are coming from but as I bought both cars at sub 1k in total, I don't think it would be cheaper in the long run as finding a decent rev 3 turbo for that sort of money may prove to be difficult.

[ambuletz]

try visiting imoc.co.uk.
buying a rev3 turbo would probably hold its value bette, so you'd have a better time selling it on

[colj]

ambuletz said:

try visiting imoc.co.uk.
buying a rev3 turbo would probably hold its value bette, so you'd have a better time selling it on

I have posted there and on mr2oc too.

I agree on the future sale value but I'm looking more at the benefit of being able to build / restore a turbo engine that I will know is of a good standard rather than selling both the uk and turbo car and buying another turbo only to find I then have to spend money to put things right.

[Baryonyx]

It may be possible to do this. You'll want to add the Turbo instrument cluster too, as it has the boost guage in the centre of the binnacle.

Best of luck with the project. Were you coming to this one fresh I'd have suggested buying a Rev 3 onward Turbo and just enjoying the car without having to fiddle with it. They should mod up easily enough, modify the exhaust a little, up the boost and 300bhp is easily achievable on stock internals!

Yes, I quite like the MR2 Turbos, I've had a lot of fun with mine. The drive home from work this afternoon was particularly good as the roads were quiet and bone dry!

[colj]

Baryonyx said:

It may be possible to do this. You'll want to add the Turbo instrument cluster too, as it has the boost guage in the centre of the binnacle.

Best of luck with the project. Were you coming to this one fresh I'd have suggested buying a Rev 3 onward Turbo and just enjoying the car without having to fiddle with it. They should mod up easily enough, modify the exhaust a little, up the boost and 300bhp is easily achievable on stock internals!

Yes, I quite like the MR2 Turbos, I've had a lot of fun with mine. The drive home from work this afternoon was particularly good as the roads were quiet and bone dry!

TBH, hindsight says I should have bought a turbo car at the beginning but the lure of the UK car (it really was cheap as in £600 cheap)proved too strong. Then, when a full turbo car came along with history and only 53k miles, that too proved irresistible. OK, I could sell up and make a profit and then but a turbo car but as I said, I could end up with a dog.

Does anyone have an opinion on the head situation? Can the REv4 NA head be better than the current Rev 2 turbo version?

[Baryonyx]

I'm not sure about the heads to be honest. Check the owners forums, or the part code. If it's the same aprt code go ahead and use them. That said, my feeling would be that the Turbo would have an uprated cylinder head gasket, as 240bhp from a 2 litre engine is fairly well stressed and a sturdier part could well be needed over the N/A head. (though the 3SGTE engine is known for it's toughness and reliability)

Given that they can easily tune up to 300bhp on stock internals you may be in need of an uprated head...

[gareth_r]

According to the EPC, the GE and GTE heads have different part numbers.

[deeps]

I would swap it as it is, does a NA head even fit a turbo'd engine, lower compression etc. but I'm no expert.

I have a rev 2 turbo (93), they all rant and rave about rev 3's being superior but I haven't had any problems with the rev 2. It's got basic mods, decat, air filter, boost controller, fuel cut defender, chip, suspension, and never misses a beat running at 1 bar boost, probably as quick or quicker than similar rev 3's when you consider that it has no extra weight of the side impact bars, air bags, or T bar.

60 comes up in around 5 seconds, which is a bit slow for me as I was used to a modded rx-7, but the handling and braking is fantastic, similar to the rx.

[Baryonyx]

deeps said:

I would swap it as it is, does a NA head even fit a turbo'd engine, lower compression etc. but I'm no expert.

I have a rev 2 turbo (93), they all rant and rave about rev 3's being superior but I haven't had any problems with the rev 2. It's got basic mods, decat, air filter, boost controller, fuel cut defender, chip, suspension, and never misses a beat running at 1 bar boost, probably as quick or quicker than similar rev 3's when you consider that it has no extra weight of the side impact bars, air bags, or T bar.

60 comes up in around 5 seconds, which is a bit slow for me as I was used to a modded rx-7, but the handling and braking is fantastic, similar to the rx.

Then the power difference between the Rev 2 and 3 models must be significant, as the standard Rev 3 is timed at 0-60 in 5.1 seconds. Obviously, this will be in ideal conditions but I imagine with a little tuning a time of 4.X seconds must be easily doable.

Also, with regard to the fuel cut defender chip, is that a mod on the ECU to prevent fueling cut when boosting? IIRC, I had heard of some people using this on their tuned Celica GT4's and some advised against it as the fuel cut function was for the engine's protection?

[Marf]

FCD on Rev3+ cars is not advisable. On earlier cars all the FCD does is block the boost cut by interfering with the MAP signal, this is fine because it still has the air flow meter to tell the ECU how much air is entering the engine.

Rev3+ cars(incl ST205 onwards) do not have an air flow sensor, relying solely on the MAP sensor for fuelling. Screwing with it on these cars can be terminal for the engine.

Besides which the Rev3+ ECU allows boost to 18psi anyway, beyond which the stock turbo becomes a hot air pump anyways.

300hp on a Rev2 car takes more mods to be reliable than a Rev3+ car, which can do it with bolt ons and a boost increase. AFAIK the Rev2 turbo cannot manage 300hp and is realyl inefficient past 1bar, also is the headgasket up to the task, the Rev3+ cars having multi layer steel gaskets.

I'm sure as above there are lots of guys running quick modded Rev1/2 cars, but you cannot escape that from a technical point of view the Rev3+ engine is a much enhanced package.

Edited by Marf on Monday 13th February 08:55

[MikeyMike]

Baryonyx said:

Then the power difference between the Rev 2 and 3 models must be significant, as the standard Rev 3 is timed at 0-60 in 5.1 seconds. Obviously, this will be in ideal conditions but I imagine with a little tuning a time of 4.X seconds must be easily doable.

Also, with regard to the fuel cut defender chip, is that a mod on the ECU to prevent fueling cut when boosting? IIRC, I had heard of some people using this on their tuned Celica GT4's and some advised against it as the fuel cut function was for the engine's protection?

Rev 2 Turbo - 221bhp 0-60 5.7sec Rev 3 Turbo - 241-245bhp (depending on source) 0-60 5.2sec

[colj]

Thanks for the replies folks

Providing we go down the route of the complete swap into the Rev 4 UK car then whilst the engine was out I was going to change the cam belt and also change the HG to an uprated type. ARP bolts were also on the list of maybes too.

As for the turbo, after reading up a bit more, I would agree that the standard CT26 wont be good enough for the 300bhp target and that then leaves me wondering whether to try and buy a Gen 3 CT20 or a hybrid?

The issue then is cost and how far you push the boat out for ever diminishing returns.

[magpie215]

300HP is easily achievable on a rev 3 engine with stage 1 mods

not so easy with the rev1/2 engine

[colj]

magpie215 said:

300HP is easily achievable on a rev 3 engine with stage 1 mods

not so easy with the rev1/2 engine

Unfortunately, Rev 2 is all I have

[Baryonyx]

What are the dangers of tuning a Rev 1 or 2 engine to that level? Will it be the head gasket that goes first, a melted piston or a bent conrod or something like that?

IIRC the Rev 3 model also received upgraded, upsized injectors amoung other things.

[colj]

My info is that the turbo just wont give you that type of power as it will only safely handle 1 bar boost. I am also led to believe that much more than that and the fueling will need upgrading as does the HG.

[cptsideways]

Baryonyx said:

What are the dangers of tuning a Rev 1 or 2 engine to that level? Will it be the head gasket that goes first, a melted piston or a bent conrod or something like that?

Det & a very rapid melting of all things internal

[colj]

Methinks a target of 280bhp may be more sensible and achievable.