ClintUK

OK I know this is an unlikely question for this forum, probably more suited to Honda Civic owers from Bounmouth but here goes.

I have a UK 97 car with various mods including hybrid turbo, Miltek exhaust system, flowed OEM headers, 3 port boost valve, Apexi ECU and it's brilliant, 150K miles and rolling like a good one, quicker than 400bhp GTR, I know cos I got the speeding ticket.

I have honestly finished with the go faster bits.

HOWEVER, Ive been working away for 2 years in the UK and fuel prices are a little higher than I remember.

When I had the Apexi mapped I had 1.3bar as highest but lowest I could have was 0.6 bar which is the actuator pressure of the control value.

Does anyone know of a valve that would allow for a lower boost pressure, to aid in mpg.

I know its all about the right foot BUT come on we all know what its like.

Is there a simple boost control valve swap / mod I could do?
Cheers

ps - Nice to be back to the real car world from the US though (soon anyway)

dan83590

The easiest mod would be to throw the key in the bin..

Splitpin

The short answer is no, at least as far as modifications are concerned. If you have a 0.6 bar actuator you can't fit a valve to go lower than that. The only way to do so would be to adjust the actuator (if it's adjustable) or fit a weaker one (if it isn't).

If you really wanted to take steps in this area the best way forward would be to have it remapped. Or, if you have an FC Commander, drop the boost target yourself.

In the short term the best thing you can do really is learn to moderate your right foot a bit.

ClintUK

Thanks Dan - very helpfull

ClintUK

Remapping wont help as you sort of implied as thats as low as the valve will go.

I'm wondering how the 'economy' mode on the Legacy GT set up works.

Is there a way to have something like 0.2bar boost so it acts like a non turbo 2.2L-ish engine for the commute, then have the turbo nutter fun that we all enjoy when appropriate.

ClintUK

You caught me at a bad time Dan I'm afraid.

Ive had 33mpg from a whole tank and also 7mpg

Dont tell me to throw away the keys.

Splitpin

No. Dual maps are easy to do on most ECUs but you can't go as low as you're asking here. In order to run 0.2 bar boost you would need an actuator with a 0.2 bar (or lower) opening pressure plus map to suit.

You can do this without any issues. The problem is that there's no way a 0.2 bar actuator will hold 1bar+++ when you want to do the "turbo nutter" bit - it'll be blown open far too easily.

You could potentially do the above with an adjustable actuator, or two different actuators, but the problem is that you would need to fiddle around under the bonnet for half an hour changing them (plus loading altered ECU maps) in order to make the transition from "eco" to "fun" modes. I get the idea you're after some sort of pushbutton switch to do the job, so the above is likely to be some way short of your expectations.