MR2 Roadster Owners Club

The Workshop => Performance Related => Topic started by: darkstar on April 13, 2016, 14:13

Title: MR2 performance
Post by: darkstar on April 13, 2016, 14:13
Hi
I'm proud owner of 2002 MR2, very happy to buy this recently.
I never drove these type cars, used to have BMW 118
But i found this car is not that much pick up in initial gears 1,2,3
is that the way this supposed to be or do i have to get checked anything?
Possible problem area. Please somebody suggest.

thanks
Title: Re: MR2 performance
Post by: jeffsimply on April 13, 2016, 14:22
That is one of the most vague posts asking for help I've seen in a while!

Firstly, welcome to the forum and MR2 ownership.

Secondly, these are not fast cars. They're 140PS and are never going to set the road on fire. Go to a long private road (track day?) and do a 0-100 test. If it takes much more than 20 seconds then it might be worth having a compression check done. If it's around 20s (fastestlaps quotes 21s which sounds about right) then it's normal.

 MOD - Let's not stimulate doing illegal things on public roads. Text above changed slightly
Title: Re: MR2 performance
Post by: shnazzle on April 13, 2016, 14:56
Make sure you're using the power band.
Don't be afraid to go over 4500rpm,thats where the mr2 lives.

It's a high-ish compression rev happy engine. The way the intake manifold and exhaust are built make it have little torque low down. So, don't be afraid to switch down to 2nd at 40mph  s:) :) s:)  

Sent from my SM-N9005 using Tapatalk
Title: Re: MR2 performance
Post by: Jrichards20 on April 13, 2016, 15:34
I do not advise this for the longevity of your engine, but mine rarely saw under 4500rpm when accelerating, and very often came near the rev limiter.

As above, they are pretty gutless below the cam change but have great fuel economy.
Title: Re: MR2 performance
Post by: jeffsimply on April 13, 2016, 15:52
Quote from: "Jrichards20"As above, they are pretty gutless below the cam change but have great fuel economy.

Assume we are talking about 1ZZ here, what cam change do you mean?

They actually make peak torque at about 4k RPM and close to that figure from 3k RPM so definitely not gutless (relatively speaking of course) in the same way that a 2ZZ is relatively gutless (much bigger divide between low and high RPM performance).
Title: Re: MR2 performance
Post by: shnazzle on April 13, 2016, 15:54
4k is the magic number. Once you're over that you're in happy territory. Play around. Make sure your engine is nicely serviced at all times though.
It's a tough engine when treated well.

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Title: Re: MR2 performance
Post by: Bernie on April 13, 2016, 15:58
Hi & welcome might have been better form to have posted an introduction in the New Members area first !!!

Might be worth cleaning the MAF and reset the ECU

Had it been serviced recently
Title: Re: MR2 performance
Post by: Jrichards20 on April 13, 2016, 16:31
Quote from: "jeffsimply"
Quote from: "Jrichards20"As above, they are pretty gutless below the cam change but have great fuel economy.

Assume we are talking about 1ZZ here, what cam change do you mean?

They actually make peak torque at about 4k RPM and close to that figure from 3k RPM so definitely not gutless (relatively speaking of course) in the same way that a 2ZZ is relatively gutless (much bigger divide between low and high RPM performance).

Yes the 1zz, which still has the VVti technology.  m https://en.wikipedia.org/wiki/Toyota_ZZ_engine (https://en.wikipedia.org/wiki/Toyota_ZZ_engine) m   m https://en.wikipedia.org/wiki/VVT-i (https://en.wikipedia.org/wiki/VVT-i) m   but possibly cam change was wrong choice of words.

The 2zz has a similar torque to the 1zz before the 2zz lift. And which I do consider that power gutless. Its a subjective matter whether someone thinks the engine has enough power or not.

Yes the 1zz does not experience the same, kick up the arse, as the 2zz, but it is still better suited in the higher rev range.
Title: Re: MR2 performance
Post by: jeffsimply on April 13, 2016, 16:47
You mentioned a cam change so I presumed you were thinking of a 2ZZ with the 'lift' feature. 1ZZ has regular DOHC with variable timing and does nothing for high RPM power.
Title: Re: MR2 performance
Post by: Jrichards20 on April 13, 2016, 16:56
Quote from: "jeffsimply"You mentioned a cam change so I presumed you were thinking of a 2ZZ with the 'lift' feature. 1ZZ has regular DOHC with variable timing and does nothing for high RPM power.


No wasn't talking about the 2zz, but quite possible confusing myself over something else. Unless I am mistaken (not unlikely, but how do we learn) it varies the valve timing according to engine speed? (as well as other things)
Title: Re: MR2 performance
Post by: shnazzle on April 13, 2016, 16:56
vvti is active all over the rev range, nothing like the "L" in vvtL-i of 2zz. It's just there for fuel economy.
Title: Re: MR2 performance
Post by: Jrichards20 on April 13, 2016, 17:03
Anyone have any links for the explanation of continuous valve timing on the 1zz specifically?

I cant remember where I read about the valve timing according to engine speed. But would be interesting to read what the signals are for the timing change?
Title: Re: MR2 performance
Post by: JoeCool on April 13, 2016, 17:24
It's a simple rotary actuator on the intake cam that varies valve opening times with revs, and the the ignition timings are controlled by the ecu. I have a white paper on its operation at home, I'll link it when I get back.

The 'lift' on the 2zz is a separate set of valves that lock the high lift cams followers into play and come in at a fixed 6,200rpm.

It's not really fair to say that vvti does 'nothing' for revs, it's certainly tuned to maintain flow at revs, it's just that it also acts to increase efficiency lower down.

It's not particularly advanced as vvti systems go. Doesn't even control the exhaust cam opening (IIRC).
Title: Re: MR2 performance
Post by: Jrichards20 on April 13, 2016, 17:28
Thanks Joe   s:) :) s:)  

That was my understanding that it does increase efficiency lower down in the rev range and alters as the revs increase.
Title: Re: MR2 performance
Post by: Ardent on April 13, 2016, 21:13
You may be thinking of these in our ref section.

Well worth a read to anyone that has not seen (stumbled across) before.

 l viewtopic.php?f=46&t=12489#p152760 (http://www.mr2roc.org/phpBB3/viewtopic.php?f=46&t=12489#p152760) l
Title: Re: MR2 performance
Post by: darkstar on April 26, 2016, 10:45
Thanks Guys for all the information
I've replaced the manifold, so not to worry about precat
Got it serviced. As some of you said, once I cross 4k rpm, this is fantastic.
But this car is unlike BMW, initial start from a traffic lights etc., is bit slow. I was expecting this will quickly move from standstill, which is not.
Title: Re: MR2 performance
Post by: shnazzle on April 26, 2016, 11:00
Quote from: "darkstar"Thanks Guys for all the information
I've replaced the manifold, so not to worry about precat
Got it serviced. As some of you said, once I cross 4k rpm, this is fantastic.
But this car is unlike BMW, initial start from a traffic lights etc., is bit slow. I was expecting this will quickly move from standstill, which is not.

yet...if you get it right..it's around 7 seconds, which is not slow either. Where I find it lacking power most is mid-range, for example when the a$$hole in front of you doing 50 on the right lane finally decides the clouds are in the correct formation for him to move to the left and you put your foot down to get to 70 (...no more..of course)... It feels like you have to wait until you've grown a beard before you get there,.
Title: Re: MR2 performance
Post by: Jrichards20 on April 26, 2016, 11:16
Quote from: "shnazzle"
Quote from: "darkstar"Thanks Guys for all the information
I've replaced the manifold, so not to worry about precat
Got it serviced. As some of you said, once I cross 4k rpm, this is fantastic.
But this car is unlike BMW, initial start from a traffic lights etc., is bit slow. I was expecting this will quickly move from standstill, which is not.

yet...if you get it right..it's around 7 seconds, which is not slow either. Where I find it lacking power most is mid-range, for example when the a$$hole in front of you doing 50 on the right lane finally decides the clouds are in the correct formation for him to move to the left and you put your foot down to get to 70 (...no more..of course)... It feels like you have to wait until you've grown a beard before you get there,.

  s:lol: :lol: s:lol:  

As for the start from traffic lights, not great for your clutch, but keep the revs high and it should pull away not too badly as Shnazzle has said  s:) :) s:)
Title: Re: MR2 performance
Post by: cptspaulding on April 26, 2016, 11:30
Quote from: "Ardent"You may be thinking of these in our ref section.

Well worth a read to anyone that has not seen (stumbled across) before.

 l viewtopic.php?f=46&t=12489#p152760 (http://www.mr2roc.org/phpBB3/viewtopic.php?f=46&t=12489#p152760) l

Thanks Jase. I got as far as "taper squish" before I realised I had glazed over & stopped reading. Is this a record?
Title: Re: MR2 performance
Post by: Ardent on April 26, 2016, 12:37
 s:lol: :lol: s:lol: