158bhp to 173bhp

[Keith]

Hi all, I have a rev1 and wonder if anyone knows how Toyota got the extra power for the later revision cars? I've also heard people say you get no gain from bolt-on parts like induction kits and exhausts, does anyone know if this is right?

Cheers
Keith

[Stef Derner]

Why do you want the extra power? A rev 1 NA is 1/2 a second quicker to 60 than the rev3 on NA, cos of the extra torque the T-VIS gives. The extra few bhp of the rev 3 on will only give them a couple of mph on you.

Torque = a quick car
Power = a fast car

What do you want? Remember you'll never have it flat out.

[Keith]

I didn't know the early cars accelerated better than later ones, but I would be more concerned with a 30 - 70 figure (or 30-90!!) than 0 - 60. That is probably more useful to me as it's acceleration for overtaking that I'd most like to improve. Also my car feels like it holds back at full throttle up until 5,000 rpm or just over, and having driven one other MR2 which was a 1994 (M) car, it didn't hold back and was smoother up through the rev range from about 2,500 to just over 6,000.

I'm quite new to MR2s having only owned one for just over a year and have picked up some very useful information from the people on this site, but I don't know what T-VIS stands for. Is there maybe some problem with my car causing the holding back? It always starts after about 6 compression strokes when cold, and 2 or 3 when warm. I haven't noticed any misfiring except a couple of mornings when the weather has been very damp and then it ran clean after a couple of miles. It's due a service in just under a thousand miles so I'll put some new HT leads on it then anyway.

All thoughts appreciated
Keith

[madbadweasel]

Stick a turbo engine in there

[Frustrated Pilot]

yes keith youre right.. no power increase... BUT.. it sounds nice.. and if youre clever u can buy lighter parts and make car accelerate faster... marginally..but i know for a fact that if u have a rev 3 tuby standard and spend 2k in total on the engine, youre looking about 300bhp give or take a few.. (my mate has the graphs to proove it) also its on my site.. 293 before he got light weight flywheel + clutch and S/S straight through exhaust.

Now, on an n/a if u spend 2k you will be lucky if you get 200bhp.

i mean its still 3k for a beams vvti engine transplant.

so best to save ya cash for a tubby transplant. ie. get the things like breaks shocks springs all ready for the tubby engine.. thats what im doing.. hehehe im just ready 4 the engine

[JJ]

To answer keiths question :

Redesigned head ad later block design with 2 piece sump, improved oil delivery.

Where the power increase comes from is the increase flow designed head, which unfortuntely is also a narrow port head... but the theory behind is increase gas velocity !!

The throttle bodies larger, the 4 brand exhaust pipes is larger as too the exhaust system. Different injectors too running a slightely difference fuel pressure on the rail !

I've just done a rev 3 normally aspirated conversion on a rev 2 and to be honest, it goes like stink compared to the earlier models - yet i was the one always critising the lower overall power of the later units - couple of tweeks though.. but it certainly shifts !!

You'll also notice the rev 4's actually dropped in power to 168 bhp... this is due to many rev 3's emissions being a tad high for mots and stuff that they introduced the EGR ( exhaust gas recirculating valve ) onto the engine ... which basically re-circulated some of the exhaust gases back into the intake !!

Further development on the exhaust downpipes too !! even larger !!

[Keith]

Thanks for the feed back guys. I understand the reasoning behind going the tubby route but it's not an option for me as I don't have enough money to do it, a couple of hundred quid is one thing, a couple of thousand is something else!! I also use the car as every day transport and from what I have read on here the tubby is nothing like as reliable as the N/A.

Thanks JJ for providing the information I was really looking for, my thinking being that if ancilliary equipment (like the dizzy, air intake system etc) was the answer, and were interchangable, it would have seemed a realistic option. But if you need a block and head then you're talking about a complete engine change anyway, so would rev 3 throttle body, injectors, exhaust manifold and system produce a worthwhile gain in performance?

Cheers
Keith

[madbadweasel]

To do that you need the Rev 3 Head anyway!!! Its easy, You dont need to take the whole engine out to replace the head, only the head! And you get to replace the head gasket and cambelt, so its peace of mind as well

[Keith]

But it sounds like Toyota thought it necessary to improve the lubrication from reading JJ's post, hence the block and sump change. From a practical viewpoint it sounds like it will be beyond what I have facilities to do myself or can afford to have done but I am still enjoying the discussion and I do appreciate you guys sharing your knowledge and time.

And you get to replace the head gasket and cambelt, so its peace of mind as well

Hmmm, sadly the head gasket had to be changed only a couple of weeks after getting the car, so just over a year ago. My mate who did it for me would NOT do it again just 'cos I want to go quicker, he hated doing it when it was necessary, and I wouldn't ask him to do it just for me to have more fun!!!

Thanks
Keith

[Rogue]

A rev 1 NA is 1/2 a second quicker to 60 than the rev3 on NA, cos of the extra torque the T-VIS gives.

IIRC, Toyota's quoted figures only show a difference of 0.1 seconds between revisions, although I beleive you are correct that it favours the early cars... Revision 1 in particular since these don't require catalytic converters.

Remember you'll never have it flat out.

Pah, you're not trying hard enough.

Rogue

[roojai]

I really wouldn't bother trying to use rev 3+ tech to mod your car. It's just as fast, if not faster. And it can steer sharper (if you can control that back end).

[JJ]

my thinking being that if ancilliary equipment (like the dizzy, air intake system etc) was the answer, and were interchangable, it would have seemed a realistic option. But if you need a block and head then you're talking about a complete engine change anyway, so would rev 3 throttle body, injectors, exhaust manifold and system produce a worthwhile gain in performance?

Dissy will interchange, entire intake manifold is difference and throttle body and exhaust manifold !! again, new front pipe needed to be bought too due to the exit flange being larger onthe later models.

Don't forget to add ecu to that list too !

In summray, for the work involved, not much gain. You'd be better off just sourcing some HKS 264 duration cams and stickign them in... will certainly give you more power than the rev 3 swap ... cost involved - two cams, cam gears if your interested, timing belt and some camshaft oil seals ... a quick reshim and someone competend to carry out the work !

[Dale_V]

cost involved - two cams, cam gears if your interested, timing belt and some camshaft oil seals ... a quick reshim and someone competend to carry out the work !

How much are we talking for that little lot JJ? (fitted)

[Pete J]

What do you want? Remember you'll never have it flat out.

Guy in a Fiat Coupe lost his bottle or was owned on the way home from Boxhill last night.

Up the inside

He could run, but he certainly couldn't hide. Maybe I should have waved as I passed at <edit>faster than him</edit> MPH

[JAP BOY]

Kieth mate my car is a 91 N/A with 187hp and 170lbs of torque all it needs to do this is the parts a decnt tuning garge and a rolling road session! also keith induction kits and exhausts do make a diffence to these car u might not see as big a difference as what the tubby guyz get but itz a gain also an after market ecu shud help with the 5000rpm coming alive bit

[Leon.]

You'll also notice the rev 4's actually dropped in power to 168 bhp... this is due to many rev 3's emissions being a tad high for mots and stuff that they introduced the EGR ( exhaust gas recirculating valve ) onto the engine ... which basically re-circulated some of the exhaust gases back into the intake !!

Having a rev 4 I do know about this restriction, but was just wondering if you knew where the EGR was, and if it is easy to remove? I'm intending on getting a custom exhaust but presume this valve is up near the manifold, and so I wouldn't be able to get rid of it when replacing the exhaust?

Cheers

[roojai]

I would be tempted to stay with the stock induction and not got too mad on the exhaust, or you will end up losing loads of low-down torque. I drove my 1991 Mk2 (NA) with a K&N for about 12 months before getting rid of it forever - a lot of noise for little or no improvement in *useable* performance.

On an NA, be happy with what you have, or go the cams route JJ mentioned.

Rolling roads can be inaccurate. I had a long steep hill on which I hit terminal velocity, and I tried totally standard, and various induction kit exhaust mods combinations, and to be honest it ran just as well as standard.

[Leon.]

I would be tempted to stay with the stock induction and not got too mad on the exhaust, or you will end up losing loads of low-down torque. I drove my 1991 Mk2 (NA) with a K&N for about 12 months before getting rid of it forever - a lot of noise for little or no improvement in *useable* performance.

On an NA, be happy with what you have, or go the cams route JJ mentioned.

Rolling roads can be inaccurate. I had a long steep hill on which I hit terminal velocity, and I tried totally standard, and various induction kit exhaust mods combinations, and to be honest it ran just as well as standard.

Fair enough but I also put a K&N on my rev 4 and it made quite a difference - definately more throttle response, without losing any noticeable torque - the torque is crap anyway low down so I'm up for gaining top end power!! The difference in engines between your '91 and my '98 means they probably respond differently to these mods - mine's probably much more restricted anyway.........

I also love the noise!! The exhaust would be an extension of the noise, a cosmetic update and I'm pretty sure a power benefit, especially with a decat pipe in place. Like I say, not bothered about low end torque cos there isn't any anyway!!

[roojai]

Fair enough but I also put a K&N on my rev 4 and it made quite a difference - definately more throttle response, without losing any noticeable torque - the torque is crap anyway low down so I'm up for gaining top end power!! The difference in engines between your '91 and my '98 means they probably respond differently to these mods - mine's probably much more restricted anyway.........

I also love the noise!! The exhaust would be an extension of the noise, a cosmetic update and I'm pretty sure a power benefit, especially with a decat pipe in place. Like I say, not bothered about low end torque cos there isn't any anyway!!

Completely agree. The sound can add a lot to the driving experience, and throttle response is great with an induction kit. A well chosen exhaust can provide a good soundtrack, great looks and possible better throttle response + top end power, and an induction kit can add to this.

Also remember that the (low down) torque on a rev1/2 Mk2 is quite a bit better (compared to top-end power) than on a rev 4, so there is more to lose. And the rev1 often comes without a cat....

I found the induction kit added to the sound very nicely, and used it for about a year. Drove everywhere at +5000rpm and loved tunnels. I stopped after I decided that the overall performance of my car did not justify the noise on a day to day basis, and I found the car to run a lot better on stock induction. It was just much nicer to drive. It felt faster as it felt like it ttok less effort. The 5-Zigen exhaust I had made a nice noise anyhow.

Best mods on an NA Mk2 MR2 (in my opinion):

1) very very good tyres, on very light alloys. Good tyres can cost loads but they are normaly worth every penny
2) Slightly lowered/stiffened suspension (on rev 1 at least)
3) Good exhaust for looks and sound
4) TRD quickshift
5) fix leaks on t-bar and rattly droplinks
6) good sound system
7) ensure nice leather/suede interior.

[Leon.]

I found the induction kit added to the sound very nicely, and used it for about a year. Drove everywhere at +5000rpm and loved tunnels. I stopped after I decided that the overall performance of my car did not justify the noise on a day to day basis, and I found the car to run a lot better on stock induction. It was just much nicer to drive. It felt faster as it felt like it ttok less effort. The 5-Zigen exhaust I had made a nice noise anyhow.

Again, the rev1/2 and rev4 difference obviously does make quite a difference to the results of induction kits. I actually find the car feels faster with it, and runs much smoother too. After fitting it, it really felt like I had allowed it to breath at last!

Have to say I don't find the sound a problem at all. I am quite happy going along at 2,500rpm with virtually no noise, or cranking it up to get a really nice deep burble - that's what's great about it, you don't get the noise when cruising, but if you want it, plant it