mr2 questions

my friend just bought an mr2 and it got beat by a stock spec V. there has to be something wrong with it. It runs fine and he drives better than me. Is there maybe a way the turbo was turned down? cuz i mean even if it was ragged on bad it shouldve still beat the spec v. and how many lbs of boost can u push on a stock mr 2. IT's a 1991.

are you sure it's a turbo? and are you sure it's the fault of the car?

I test-driven some amazingly beat turbo MR2s that ran terribly.

As for your boost question, I would not go over 15 psi with the factory turbo. If you upgrade the turbo and make the necessary modifications to the rest of the system you can run a lot of boost. I am currently racing at 23-24.5 psi on a 100% original engine with 200,222 miles.

I test-driven some amazingly beat turbo MR2s that ran terribly.

As for your boost question, I would not go over 15 psi with the factory turbo. If you upgrade the turbo and make the necessary modifications to the rest of the system you can run a lot of boost. I am currently racing at 23-24.5 psi on a 100% original engine with 200,222 miles.


well is it possible the boost is turned down, cuz i might be getting it. and its there a stock watsegate on them?

I test-driven some amazingly beat turbo MR2s that ran terribly.

As for your boost question, I would not go over 15 psi with the factory turbo. If you upgrade the turbo and make the necessary modifications to the rest of the system you can run a lot of boost. I am currently racing at 23-24.5 psi on a 100% original engine with 200,222 miles.


o yea and if its not the boost what can be done for them to run better cuz it only has 119 k

I've never heard of a turbo without a wastegate ... so yes, they do have a wastegate :)

The biggest place used MR2s lose power is the ignition. I suggest buying brand new TOYOTA cap, rotor and wires once a year. Get your self some new NGK copper plugs or the Toyota platinum plugs if you are not really modified yet.

I have seen MR2s down as much as 30 rwhp because of these parts.

I would also do a fuel filter, air filter and oil change and see where that gets you.

Stick a boost gauge in there so you know how much boost you are running.
It is possible that you are stuck in "low boost mode" which would only be 7 psi or so.

OEM boost should hit 11.98 psi, but under certain circumstance the ECU limits you to 7.

What kind of tires does the MR2 have?

I've never heard of a turbo without a wastegate ... so yes, they do have a wastegate :)

The biggest place used MR2s lose power is the ignition. I suggest buying brand new TOYOTA cap, rotor and wires once a year. Get your self some new NGK copper plugs or the Toyota platinum plugs if you are not really modified yet.

I have seen MR2s down as much as 30 rwhp because of these parts.

I would also do a fuel filter, air filter and oil change and see where that gets you.

Stick a boost gauge in there so you know how much boost you are running.
It is possible that you are stuck in "low boost mode" which would only be 7 psi or so.

OEM boost should hit 11.98 psi, but under certain circumstance the ECU limits you to 7.


what would make the ecu limit the boost?

*coolant temps to low
*ambient temps to low
*detonation (knock)
*others that I may not be aware of

I would also check to make sure the TVIS is opening up. If that does not open, you are only running on 4 intake valves per cylinder instead of 4.

Have you checked the codes?

What date is painted on the ignition wires?
I would really start there first.

hi temps seem to do the trick too Jeff...

Date? I thought 1998 meant 1998cc's.

ok, i'm hanging here, what exactly is a spec v? cause the only one i know it the gt-r skyline, if so there's really no surprises so it has to be something else right?

TRD2000, hi temps increases the probabilty of knock/detonation which is my 3rd bullet above.
The ECU does not limit boost pressure based just on high ambient/coolant temps ... you have to start experiencing knock first.

ok, i'm hanging here, what exactly is a spec v? cause the only one i know it the gt-r skyline, if so there's really no surprises so it has to be something else right?


a spec v is a nissan sentra se-r spec v 2.5 l cvtc 6 spd with 175 hp and its a 4 door

ahhh ok, got ya now, wouldn't have guessed that one! thanks civics!

I just knew when it got REAL hot it didn't get boost (observation) handy to know its knock not temp, Thanks Jeff

are iridium plugs good to use on the mr2

i know they are top of the line spark plugs, but i'm not experienced with the engine yet as i am with nissan's

From what I understand, iridium plugs are a bad idea in a turbocharged car.

they last longer.... that makes them good for cars like Subaru where you don't have access to them to change them...

copper plugs actually work better and give a better spark, they just don't last for 100,000km (60,000Miles)

Me and my dad bought a 1987 mr2 for $500 so you could guess it's extremely beat, we are planning to swap the engine out and i was wondering, would it be better for me to buy a new stock motor or maybe the supercharged version?