Mk1 MR2 Tuning potential?

[The DJ 27]

Any ideas of the tuning potential of a Mk1 MR2. I'm considering buying one as my next car and was wondering what I could do to it to improve the performance. I know theres a supercharger conversion about but I don't want to go that far (insurance). How much power would a sports exhaust, induction kit and high performance cams get me? This is obviously in addition to uprated suspencsion and brakes. Any help greatfully appreciated

[Mr E]

Not masses of power gain there. But it will *sound* quicker.....

[The DJ 27]

Thanks for the link, there's some good stuff on there. Any ideas how much the supercharger conversion costs and what sort of power I'd be looking at? I've had a good look at www.mr2supercharger.com but I can't find and figures

[Mr E]

The supercharger is a 4A-GZE lump to replace the standard 4A-GE is it not.

Rip the engine out, sell it to Fensport and buy a GZE to replace it......

I might be wrong of course.

I doubt simple mods (induction/exhaust) will liberate 20bhp. They don't on my Toyota, and I'm running 15psi of boost...

No idea what the cams would give.

>> Edited by Mr E on Friday 13th February 15:28

[The DJ 27]

Mr E said:

The supercharger is a 4A-GZE lump to replace the standard 4A-GE is it not. Rip the engine out, sell it to Fensport and buy a GZE to replace it...... I might be wrong of course. I doubt simple mods (induction/exhaust) will liberate 20bhp. They don't on my Toyota, and I'm running 15psi of boost... No idea what the cams would give. >> Edited by Mr E on Friday 13th February 15:28

No idea mate, I'm new to all this! I'm seriously thinking about selling my car and buying a Mk1 MR2. So I haven't even bought the car. Theres a very tasty metallic blue example on autotrader.co.uk for £1,395. It's the same engine that was used in the Corolla GTi isn't it?

[trefor]

The DJ 27 said:

Mr E said: The supercharger is a 4A-GZE lump to replace the standard 4A-GE is it not. Rip the engine out, sell it to Fensport and buy a GZE to replace it...... I might be wrong of course. I doubt simple mods (induction/exhaust) will liberate 20bhp. They don't on my Toyota, and I'm running 15psi of boost... No idea what the cams would give. >> Edited by Mr E on Friday 13th February 15:28 No idea mate, I'm new to all this! I'm seriously thinking about selling my car and buying a Mk1 MR2. So I haven't even bought the car. Theres a very tasty metallic blue example on autotrader.co.uk for £1,395. It's the same engine that was used in the Corolla GTi isn't it?

Yep, my younger brother has a Corolla GTi. Nice strong motor, people don't realise they're quite nippy. His has done 110k and is running like new.

[The DJ 27]

I have to convince my mother that it's a good idea, since I still owe over £3000 on my current car. I can pay that off and buy the MR2 with what I make from selling it though. I'm only going to be young once so I might as well enjoy myself, which I'm not going to do in a SEAT Ibiza.

[The DJ 27]

Yeah 190 bhp does sound fun in something that light. It'll be even lighter by the time I can afford that anyway. If I buy the car it'll be something to save up for. If spending £600 is only going to get me 8bhp then I might not bother, just save the money for the supercharger conversion. I'd have to pay to have it fitted as well becuase there's no way I could do that myself. Does sound tempting though

[The DJ 27]

Having had a proper look at the Fensport site, I think its fair to say that there's a fairly large scope for tuning. Now I just have to justify it to my mum :runsawayveryfast:

[Mad Dave]

You should have bought mine - it went for just over £1200 in the end - 88k miles, full leather interior, targa top, full stainless steel exhaust and loads of history.

Theyre pretty nippy in standard trim - i found mine quite fast enough

[The DJ 27]

Mad Dave said:

You should have bought mine - it went for just over £1200 in the end - 88k miles, full leather interior, targa top, full stainless steel exhaust and loads of history. Theyre pretty nippy in standard trim - i found mine quite fast enough

Probably would have done if I'd been looking for one a couple of weeks ago. I only recently decided I want one. Was going to get a Saxo VTS, but decided I want a proper RWD car

[DanBoy]

Sorry to hijack the thread but whilst we're on the subject of MR2s:

Mine's a Rev3 n/a running 175bhp. Got a K&N and a straight through S/S exhaust (not strictly legal but anyways).

As I'm going to be keeping this car for a while yet, I was thinking about possibly getting a new ECU and getting it mapped along with high lift cams and maybe a nice tubi manifold... I'd like to see a bit over 200bhp.

Anybody got any ideas on how much that'd cost? If it's gonna cost silly amounts I may as well just buy a tubby (although I'd rather have an n/a).

[400sedave]

www.mrtwo.co.uk

[Captain Muppet]

The DJ 27 said:

Mad Dave said: You should have bought mine - it went for just over £1200 in the end - 88k miles, full leather interior, targa top, full stainless steel exhaust and loads of history. Theyre pretty nippy in standard trim - i found mine quite fast enough Probably would have done if I'd been looking for one a couple of weeks ago. I only recently decided I want one. Was going to get a Saxo VTS, but decided I want a proper RWD car

For your first RWD car I'd keep it standard until you've learnt to slide it around a bit. 122bhp doesn't sound much but then they only have narrow 185 tyres. I used to slide mine (both of them) about all the time and the only time you'd need more power is when you're racing someone. As I'm not a cock I never raced anyone, so it didn't matter.
Spend the money on new dampers - the single most effective fun/pound change I did to either of my mk1s.

Avoid the temptation to fit wider tyres - more grip=less fun.

Supercharged mk1s can be a liability as the supercharger clutch is ECU controlled and can cut in when you don't need that much extra power (like accellerating through a bend).
A friend of mine has the supercharger cut in while accellerating on a straight road just as the tarmac changed - the car span and he drove up a tree...

[The DJ 27]

The supercharger would be the last thing to go on the car. Brakes and suspension first, then make it go quicker in a straight line. Make it lighter as well before I start playing with the engine.

[The DJ 27]

400sedave said:

www.mrtwo.co.uk

Why did you post this link? I will have even less money than the none I already have because of that website. Some very tasty stuff on there

[Mr E]

Fuel Cut is there for a reason mate. It kicks in when the ECU has no mappings for that level of boost.

I have maps for 17.5 psi (about 1.1 bar). Any more than that, the ECU doesn't know what to do and cuts fuel.

Now, if you remove the safety net, the car will keep pulling. But you could end up running high boost on insufficient fuel.

Do you *really* want to run lean at 14psi and 6000rpm.

Do you *like* rebuilding engines?

If you're going to do it, you need a ecu/fuel system. And about 6 hours of RR time to map it correctly. Which is significantly expensive.

I'm looking at a downpipe that frees up a couple of PSI. This will get me into the 300+ club, but I might well see boost creep as the wastegate can't cope with that little backpressure. FCD will prevent me melting a piston.....

....I hope.

[deltaf]

Also dont forget that the standard injectors will run out of capacity at around 16 psi of boost level.
Also the air flow meter will be topped out and wont read correctly so youll get a lean running condition at W.O.T. (wide open throttle), the fuel pump hasnt got enough capacity either.
Also the pistons will likely have a problem at around 16 psi (fensport showed me one)
Im currently running (well i was) 14.7 psi just to keep things within check.
The fuel cut defencer is NOT needed.
Why?
Simple. The injection method used on MR2/GT4(ST185 only) is the same, ie: mass air flow method.
You want more boost? So plumb in a bleed valve to the wastegate actuator, and then remove the vaccum/pressure feed line to the "map" sensor.
This sensor is NOT used in the MAP role in a mass air flow measurement system.
All it controls is the "boost" gauge(useless on GT4) and initiates fuel cut in the ecu.
How do i know this? Ive been running in this mode of operation for at least a year with no problemas whatsoever.
The speed/density method of air flow measurement DOES use a MAP sensor, so itd be foolhardy to remove it if it was fitted with this system, ie Mr E's ST205 system.
If your car has an air flow meter then you can raise boost with the fuel cut defencer using the method ive described.
If it NOT got an air flow meter then youll need to disable fuel cut by some other method.
HTH.

[Mr E]

Gazboy said:

little bit more

Slippery slope mate. Just look at DeltaF's beast.....

.....and I have a horrid feeling I'm going the same way. Decat is £200 and will lead to 16.5 - 17psi.

300bhp ish. About the limit on the stock engine. Which then means I need forgies, hybrid turbos and aftermarked fuelling to do things right. And if I'm spending that sort of money, you may as well go for *big* power.....



Delta, as an aside - if you have a downpipe have you had any issues with boost creep. Apparently a 3" straight through system is more than the wastegate can handle, and you get boost creep leading to fuel cut.....

[deltaf]

Dunno about that Mr E.
The downpipe i have on replaced the "thermal reactor" catalyst that was fitted and its about 2.5 inch diameter.Did tend to notice drop off in power tho occasionally, but was more a heat soak problem with the standard intercooler i reckon.

The new turbo and wastegate actuator are hybrids from Turbo Technics. I presume the actuator was sized to match the new turbo...
Am just getting together the parts to start the rebuild anyway, as its done 100,000 miles. Still, it was pretty tight for an engine of that age and even now it goes ok, just isnt feeling right tho....deffo got a problem somewhere....
So far i have the gaskets(minus the head gasket....gotta be steel) all the bolts...head stud kit, main bearing stud kit and new flywheel bolts (all ARP)...next will get the head gasket and forged pistons and a set of Arrow "H" section rods.
After that its gotta have the shimless tappet conversion(hate shims) and Delwest titanium valves...along with new springs and cams to suit.
If that lot dosent liberate the 400 ponies im after then nothing will!!

Oh nearly forgot, Gazboy, ive seen an MR2 with 640 bhp using the standard crank! Its got that much torque that it wheelies! Ill try and find out the url so you can have a dribble m8.





>> Edited by deltaf on Wednesday 25th February 15:27