Programmable ECUs

[paulrockliffe]

Swapping a Nissan Micra engine into a Mini and have just bought a set of ZX6R throttle bodies to make it more of a challenge.

Discovered your bikes have two butterflies in each throttle. Bizarre.

Anyway, does anyone know whether the second one is controlled only by engine speed?

And does anyone understand the reason why it's there in enough detail to know whether it's worth keeping on a 1.3 engine running at half the speed?

And now I'm thinking my best bet for ECU to make it work will be a bike one that's expecting the second butterfly, what are my options?

Random questions I know, but I figured if anyone can help they'll be here.

Thanks!

[Krikkit]

No it's not worth it! Commonly found on French hatches looking for cheaper bodies.

Best bet is a DTA, but they are a bit pricy. Mega squirt also works quite well but isn't as fancy or backed up with the same level of support.

P.s. Two throttles for safety I believe, if one butterfly is stuck then another closes it off, better losing a tiny smidge of performance than risking a stuck throttle on a bike

Edited by Krikkit on Wednesday 19th September 22:47

[gareth_r]

This is about Suzuki's SDTV (Suzuki Dual Throttle Valve) system, but I assume the Kawasaki one would do something similar.

http://wodocs.com/docum/30-suzuki-gsx_r1000-22.htm...


It seems that the secondary throttle is often removed on GSXRs (at least it is according to Google )


EDIT: This is what Kawasaki say >>>> https://www.kawasaki-cp.khi.co.jp/technology/engin...

Edited by gareth_r on Wednesday 19th September 23:35

[2ndclasscitizen]

They're designed specifically for the ZX-6R and are controlled dependent on engine speed + throttle position. Take them out.

[Rubin215]

Will they flow enough air for you?
Designed for a cylinder that is less than half the capacity?

Might be fine at tickover/low revs, but might be a bit asthmatic as you open it up.

[Steve Bass]

Rubin215 said:

Will they flow enough air for you?
Designed for a cylinder that is less than half the capacity?

At nearly three times the rpm

Regarding the secondary butterflies just wire them open. No need to have them working on a car engine. Far bigger rotational mass so won’t be sensitive to ham fisted throttle application

Edited by Steve Bass on Thursday 20th September 06:30

[paulrockliffe]

I thought. IE I read last night, that the second throttle is to increase the powerband by increasing gas-flow velocity at lower revs. It's effectively creating a smaller port, higher pressure and higher gas speed, so more ram effect. The ports are sized for high rpm, so too big at lower speeds.

Is that correct?

I know I can remove them, but couldn't work out of they would do anything on the larger engine at lower RPM, I guess they would. And then figured a custom bike ECU would let me keep them.

This is a fairly normal mod for the engine is going on, I'm putting it in a Mini so this is cheaper than having a plenum made to fit the space. And more of a challenge. If it doesn't work I've not lost much, about £300 that I wouldn't have had to spend anyway, so worth a try.

[Krikkit]

paulrockliffe said:

I thought. IE I read last night, that the second throttle is to increase the powerband by increasing gas-flow velocity at lower revs. It's effectively creating a smaller port, higher pressure and higher gas speed, so more ram effect. The ports are sized for high rpm, so too big at lower speeds.

Is that correct?

I know I can remove them, but couldn't work out of they would do anything on the larger engine at lower RPM, I guess they would. And then figured a custom bike ECU would let me keep them.

This is a fairly normal mod for the engine is going on, I'm putting it in a Mini so this is cheaper than having a plenum made to fit the space. And more of a challenge. If it doesn't work I've not lost much, about £300 that I wouldn't have had to spend anyway, so worth a try.

Bike bodies adapted to small car engines have been done to death, and no-one bothers keeping the second throttles. Given some are being used on very well developed race engines I can't see that you'd see any real improvement.

You've also got the difficulty of adapting the bike ECU to the engine sensors etc, better off using standard car management imo.

[fergus]

Dave Walker and Karl at Emerald offer a great product and fantastic support, both in implementation and mapping assistance.

http://www.emeraldm3d.com/

Their ECUs have 99% of the functionality of the big boys, MoTEC, etc, but at a fraction of the cost. You also don't need to pay to unlock functionality, a la MoTEC and friends.

[paulrockliffe]

Krikkit said:

Bike bodies adapted to small car engines have been done to death, and no-one bothers keeping the second throttles. Given some are being used on very well developed race engines I can't see that you'd see any real improvement.

You've also got the difficulty of adapting the bike ECU to the engine sensors etc, better off using standard car management imo.

Thanks, yeah that was my initial thought, but wasn't sure if it was possible to use a bike ECU and leave everything as it is on the inlet side. If the second throttle is only linked to engine speed then it should be easy enough to do. Then I wasn't sure if there was any benefit anyway as the engine is completely different.

What sensors are on the engine, I've not investigated, but was thinking there's a crank position sensor and possibly engine temperature. There's an exhaust gas sensor, but that'll need adapting anyway, then the rest are on the throttle bodies - MAP, throttle position (x2).