Bit more power from a Rev5 N/A?? Advice needed, its for charity!

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MR2Simon
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Bit more power from a Rev5 N/A?? Advice needed, its for charity!

Post by MR2Simon »

Hi guys.

Fishing for information here i guess.... I bought a Rev5 as I wanted a very late car, with all the development benefits that normally follow naturally along the way. That and less rust!

Very happy with the car, however it seems I have signed myself to a bit of a 12 month charity driving challenge, details of which I'll post up when it is all confirmed.

As such I'd like to get the most out of the car, performance wise. I understand there were emissions restrictions which limited the power of the late model cars. My question is, is this all easily reversible, and if so how would one go about doing it?

What do I have so far? This is what has come with the car.

An induction kit of some sort, with a cone filter.
Custom built stainless exhaust, which is a little loud but bearable.

Thats about it as far as I can tell.

Its not what I bought the car for, but I've stumbled across this opportunity by happy coincidence. Seems a good chance to have some fun with the car, and raise money for a worth charity at the same time! \:D/

The year is going to cost me a tidy sum of money just to participate, so any alterations I make need to be either very cheap or free/gifted!

I'll keep you all posted, and when I get more info I'll post it up!

Thanks in advance. Simon
Last edited by MR2Simon on Tue Jul 15, 2014 12:44 pm, edited 1 time in total.
Draven
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Re: Bit more power from a Rev5 N/A?? Advice needed, its for charity!

Post by Draven »

Not much you can do i'm afraid.. the N/A isn't really tunable on a budget. You have to spend lots of money to eek any more power out of it. You've got all the mods already that should give you a little more power.
Draven
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Re: Bit more power from a Rev5 N/A?? Advice needed, its for charity!

Post by Draven »

I would be looking to do a thorough service.. plugs, leads, disty, rotor, coolant, oil, fuel filter, etc etc..

A healthy well serviced engine will produce more power than one that hasn't been serviced.

:thumleft:
Draven
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Re: Bit more power from a Rev5 N/A?? Advice needed, its for charity!

Post by Draven »

You could remove the CAT inbetween MOT's but police do have the power to do a spot check and you do not have the loop hole with a rev5 N/A that rev3 turbo owners have.

You can also look at making the car lighter. Removing the aircon if you've got it is a good start.

Really depends on how far you want to go.
Peter Gidden
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Re: Bit more power from a Rev5 N/A?? Advice needed, its for charity!

Post by Peter Gidden »

Removing the cat might gain you a few single figure HPs. And make the car illegal. IMHO, not worth the bother.

The OEM air filters have been proven to flow 270HP, so you'll gain nothing in reality apart from an induction roar.

As stated, just keep the car well maintained.
MR2 Rich
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Re: Bit more power from a Rev5 N/A?? Advice needed, its for charity!

Post by MR2 Rich »

What about making it lighter?
No 2 :(
MR2Simon
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Re: Bit more power from a Rev5 N/A?? Advice needed, its for charity!

Post by MR2Simon »

Thanks guys

To be fair, modifying the car too much will kind of detract away from the purpose of the project.

I'll maybe loose some weight for the timed stuff, apart from that a good set of pads and a thorough check over and service of all wear and tear items.

Cam belt was 2 years ago with a water pump, so should be good to go.

Going to be a lot of fun me thinks!

Simon
shinny
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Re: Bit more power from a Rev5 N/A?? Advice needed, its for charity!

Post by shinny »

It depends what the challenge is.. on an NA, the best ways of going faster would be:
1) Driver training
2) ARBs
3) Track tyres (eg R888s)
4) Lowering springs

Unless you strip it out, there's not much you can do to make it accelerate faster. However the biggest performance bottleneck in most cars is between the steering wheel and the seat, and simply getting yourself to drive more aggressively is a good way to become more dangerous on the road. Do a skid pan, do IAM, get some track tuition and make yourself a better driver. You can also make the car go round corners faster. A set of sticky track rubber will vastly increase the available grip and thus the car's cornering capability (which is NOT the same as the safe speed to corner on the public roads). I wouldn't daily drive track rubber though, so we really need more details of what this "challenge" entails.
Donato
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Re: Bit more power from a Rev5 N/A?? Advice needed, its for charity!

Post by Donato »

You can squeeze a few more ponies by fitting one of these;

http://www.ebay.co.uk/itm/Toyota-MR2-Ce ... 1326164540

I felt a big difference in torque when I fitted mine. Apart from that, they aren't that tuneable. Performance exhausts are rare and expensive to come by!
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Re: Bit more power from a Rev5 N/A?? Advice needed, its for charity!

Post by Draven »

MR2Simon wrote:Thanks guys

To be fair, modifying the car too much will kind of detract away from the purpose of the project.

I'll maybe loose some weight for the timed stuff, apart from that a good set of pads and a thorough check over and service of all wear and tear items.

Cam belt was 2 years ago with a water pump, so should be good to go.

Going to be a lot of fun me thinks!

Simon


What about oil and fuel filter.. Fuel filter is often over looked when doing maintaince and they aren't expensive or difficult to replace.
toxo
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Re: Bit more power from a Rev5 N/A?? Advice needed, its for charity!

Post by toxo »

No one seems to have picked up on this...

MR2Simon wrote:I understand there were emissions restrictions which limited the power of the late model cars. My question is, is this all easily reversible, and if so how would one go about doing it?


I think you are talking about the EGR system which trimmed 7-8bhp off the later N/A cars (UK ones anyway).
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shinny
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Re: Bit more power from a Rev5 N/A?? Advice needed, its for charity!

Post by shinny »

toxo wrote:No one seems to have picked up on this...

MR2Simon wrote:I understand there were emissions restrictions which limited the power of the late model cars. My question is, is this all easily reversible, and if so how would one go about doing it?


I think you are talking about the EGR system which trimmed 7-8bhp off the later N/A cars (UK ones anyway).


Generally EGR systems are only functioning when the engine is idling, right? It's my understanding that EGR deletes don't actually give you any power, they just make you a little more polluting at idle. I've also heard (although can't immediately point to evidence) that power output figures had some industry standardisation applied to them around the time of the rev4, hence why the engine magically lost 4 bhp.
toxo
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Re: Bit more power from a Rev5 N/A?? Advice needed, its for charity!

Post by toxo »

I'd have thought that if some standardisation (to DIN HP, or kW then converting afterwards or whatever) occured at that time it's very coincidental (but entirely possible). The rev3 n/a in both UK and Jap markets has a published 175bhp, the rev4 and 5 n/a in UK have 168 but in Japan (excluding the BEAMS) retain 175. Seems to me that the change is very specific and occurs at the same time as a physical modification to the engine. As far as I'm aware, the only other change electrical or engine management wise is the addition of an ECU immobiliser.

Edit: Actually now I think about it there was a change in the manifolds at some point from 4-2-1 to 4-1 which I suppose could account for some additional difference in peak output. Again it would be a negligible amount I expect.
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shinny
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Re: Bit more power from a Rev5 N/A?? Advice needed, its for charity!

Post by shinny »

toxo wrote:Edit: Actually now I think about it there was a change in the manifolds at some point from 4-2-1 to 4-1 which I suppose could account for some additional difference in peak output. Again it would be a negligible amount I expect.


I always thought that was a rev2 to rev3 thing. IIRC the 4-1 is better for peak power and the 4-2-1 better for torque... which wouldn't explain a loss of peak bhp on the rev4.
jon
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Re: Bit more power from a Rev5 N/A?? Advice needed, its for charity!

Post by jon »

The Rev 4 (and presumably Rev 5) UK ECU is completely different to the Rev 3 ECU. Internally it only has a single PCB rather than the 2 PCB in earlier ECUs. A lot of the discreet ICs inside the ECU have been integrated into a huge 100-pin custom IC presumably to reduce production costs.

This re-design may be the cause of at least some of the lost BHP.
toxo
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Re: Bit more power from a Rev5 N/A?? Advice needed, its for charity!

Post by toxo »

Well that proves I don't know what I'm talking about :lol:
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jon
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Re: Bit more power from a Rev5 N/A?? Advice needed, its for charity!

Post by jon »

toxo wrote:Well that proves I don't know what I'm talking about :lol:

To be fair, until I opened up an Rev 4 ECU I had assumed it was just the Rev 3 ECU plus an immobiliser as well. :D
MR2Simon
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Re: Bit more power from a Rev5 N/A?? Advice needed, its for charity!

Post by MR2Simon »

Thanks for all the replies guys.

I may well look into the EGR thing a little more to see what exactly it's effect on performance is.

Recycled exhaust gasses are most defiantly not good for performance and the valves are known to seize and loose a lot of low down power. Not good!
shinny
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Re: Bit more power from a Rev5 N/A?? Advice needed, its for charity!

Post by shinny »

MR2Simon wrote:Thanks for all the replies guys.

I may well look into the EGR thing a little more to see what exactly it's effect on performance is.

Recycled exhaust gasses are most defiantly not good for performance and the valves are known to seize and loose a lot of low down power. Not good!


Yes - but your performance at idle is pretty poor anyway and the gases should not be recirculating with the throttle open.
MR2Simon
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Re: Bit more power from a Rev5 N/A?? Advice needed, its for charity!

Post by MR2Simon »

shinny wrote:Yes - but your performance at idle is pretty poor anyway and the gases should not be recirculating with the throttle open.


:D indeed it is, I'll not be setting any lap records at Le Mans with her sat on idle that's for sure.

Checking its operation and function is, I would have thought, a fairly sensible thing to do considering the potential issues caused with one being stuck open. I was surprised how much a defective EGR valve effected performance when I first experienced it. Top end power seemed relatively unaffected, everything else was significantly different.

As always, thoughts and suggestions appreciated :thumleft:
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