30 replies to this topic

[rabidh]

I'm currently looking at doing a TB conversion using the standard ECU and some GSXR TBs. My plan is to cut up an ETB and jam it onto the separate TBs to control opening. Next weekend i'm off to use a CNC milling machine at a friend's work to cut out a manifold, and then we'll see if it works or just totally throws the ECU While I get Arno's point about measuring vacuum, i'm hoping it'll work out ok if there's a suitably restricted pressure change supplied to the sensor. My kit car has been running with separate carbs for years, with a vac feed going into an ECU that controls timing. I've never had a problem, but then the Z22SE's ECU is a lot more complex. Still, it can be debated for ages, but the only real way to know for sure is to try it and find out Looking at the ETB it doesn't go from fully flat to fully open - its a strange shape that makes it look like it might only move 60 degrees from fully closed to fully open. Is this the case? If so, i'm going to need some crazy lever arrangement to translate that to a proper 90 degrees movement.

[slindborg]

id rather hump a dead badger than entertain anything from the rip off merchants that are bogg bros. Ok they do a tolelrable job but they have become so well known that their prices are creeping up at an astounding rate and Im not a huge fan of their work either lol. Went and had a chat with Mr Dave at Mountune, hes a legend in my books. He showed me some roller barrel TB's that are used on the WRC focus. a snip at £1000 (come with 4 port matched carbon trumpets, and TPS)lol, but damn good. He did suggest that for road use that butterfly TB's would be best. They have some 40mm TB's that flow the same as Jenvey 45mm items due to jenvey using a girder for the throttle spindle and the mountune ones using a near flat/invisible butterfly. I only want a nice easy 200bhp and they will try to work out a good option for that route. but its not gonna be "that" cheap for mountune components but they will be far superior to the jenvey/webcon items.

[speedster]

I'm currently looking at doing a TB conversion using the standard ECU and some GSXR TBs. My plan is to cut up an ETB and jam it onto the separate TBs to control opening. Next weekend i'm off to use a CNC milling machine at a friend's work to cut out a manifold, and then we'll see if it works or just totally throws the ECU

While I get Arno's point about measuring vacuum, i'm hoping it'll work out ok if there's a suitably restricted pressure change supplied to the sensor. My kit car has been running with separate carbs for years, with a vac feed going into an ECU that controls timing. I've never had a problem, but then the Z22SE's ECU is a lot more complex.

Still, it can be debated for ages, but the only real way to know for sure is to try it and find out

Looking at the ETB it doesn't go from fully flat to fully open - its a strange shape that makes it look like it might only move 60 degrees from fully closed to fully open. Is this the case? If so, i'm going to need some crazy lever arrangement to translate that to a proper 90 degrees movement.

With iTB's won't the MAP signal behaviour be quite different than the standard manifold?

From my experience the ECU is pretty fussy with sensor inputs when it's running in closed loop. For instance on WOT (open loop) I'm knocking a few precentages points off the MAP signal. To get a even throttle response and hit the right maps I start pulling back on the MAP signal prior to hitting WOT. All fine on the way up but when throttling back, and switching the ECU back into closed loop mode, if the MAP readings are too far off an internal reference point the ECU will shut down fueling. On the SACF-2 that translates into not adjusting the MAP signal by any large figure till approx 67% or more of WOT, which means on or prior to 67% WOT the MAP signal remains more or less unadjusted. (It is a pity the SAFC-2 can't seperate throttle opening and closing behaviors/adjustments.)

Be interested in seeing how you manage with the ETB control +iTB setup. I reckon a seperate floor mounted throttle pedal plus cable be alot easier though....

[rabidh]

With iTB's won't the MAP signal behaviour be quite different than the standard manifold?

I'm hoping not... In the TBs a vacuum feed is taken off each barrel via a pretty small hole and then mixed, so i'm hoping the violent pressure changes will be evened out. The pressure changes might even be evened out too much!! I'm going to make a small reserviour though with an adjustable aperture so hopefully I can tweak it.

Be interested in seeing how you manage with the ETB control +iTB setup. I reckon a seperate floor mounted throttle pedal plus cable be alot easier though....

If you have independent engine management it almost certainly would be easier to use a cable. As soon as you go down that route it gets expensive though (hacking up wiring looms, the ECU itself, etc...). This is really only for a bit of fun (and because no-one has done it before - prob for good reason ). All in its going to cost me less than £200 and its all fully reversible, so I reckon its worth a try even if it backfires totally.

[speedster]

With iTB's won't the MAP signal behaviour be quite different than the standard manifold?

I'm hoping not... In the TBs a vacuum feed is taken off each barrel via a pretty small hole and then mixed, so i'm hoping the violent pressure changes will be evened out. The pressure changes might even be evened out too much!! I'm going to make a small The though with an adjustable aperture so hopefully I can tweak it.

Be interested in seeing how you manage with the ETB control +iTB setup. I reckon a seperate floor mounted throttle pedal plus cable be alot easier though....

If you have independent engine management it almost certainly would be easier to use a cable. As soon as you go down that route it gets expensive though (hacking up wiring looms, the ECU itself, etc...). This is really only for a bit of fun (and because no-one has done it before - prob for good reason ). All in its going to cost me less than £200 and its all fully reversible, so I reckon its worth a try even if it backfires totally.

Go for it rabidh! The reserviour is a neat idea The standard maps will probably have you running lean to about 3800 RPM so don't detonate....

[alanoo]

Went and had a chat with Mr Dave at Mountune, hes a legend in my books. He showed me some roller barrel TB's that are used on the WRC focus. a snip at £1000 (come with 4 port matched carbon trumpets, and TPS)lol, but damn good. He did suggest that for road use that butterfly TB's would be best. They have some 40mm TB's that flow the same as Jenvey 45mm items due to jenvey using a girder for the throttle spindle and the mountune ones using a near flat/invisible butterfly.

I only want a nice easy 200bhp and they will try to work out a good option for that route. but its not gonna be "that" cheap for mountune components but they will be far superior to the jenvey/webcon items.

Sounds like the ones i have at home and plan to use

[slindborg]

they look good. where did you get them from? or is it hush hush lol

[Mike-F]

I'm currently looking at doing a TB conversion using the standard ECU and some GSXR TBs. My plan is to cut up an ETB and jam it onto the separate TBs to control opening. Next weekend i'm off to use a CNC milling machine at a friend's work to cut out a manifold, and then we'll see if it works or just totally throws the ECU

While I get Arno's point about measuring vacuum, i'm hoping it'll work out ok if there's a suitably restricted pressure change supplied to the sensor. My kit car has been running with separate carbs for years, with a vac feed going into an ECU that controls timing. I've never had a problem, but then the Z22SE's ECU is a lot more complex.

Still, it can be debated for ages, but the only real way to know for sure is to try it and find out

Looking at the ETB it doesn't go from fully flat to fully open - its a strange shape that makes it look like it might only move 60 degrees from fully closed to fully open. Is this the case? If so, i'm going to need some crazy lever arrangement to translate that to a proper 90 degrees movement.

Sounds almost like my plan to a Tee. But I was planing to build a slave throttle drive motor unit mounted to the bulk head with a shot cable linking to the TB's. I rekon the standard TB has a stepper motor and a feed back pot inside so planed to have the a stepper motpr driving the cable with the feedback pot mounted on the TB's for safety(incase of cable failure)

Not sure about a vaccum resovoir i think the ECU will do its own smothing in software so might make things to slow!

I was planing to get all the bits together to do this over next winter as i have only had the car 5 weeks and just want to drive it! But it seems quite slow now, and my 1.9 TD Xantia seems like somthing has dropped off as it now seems to be VERY slow



Mike

[alanoo]

they look good. where did you get them from? or is it hush hush lol

[rabidh]

I was planing to build a slave throttle drive motor unit mounted to the bulk head with a shot cable linking to the TB's. I rekon the standard TB has a stepper motor and a feed back pot inside so planed to have the a stepper motor driving the cable with the feedback pot mounted on the TB's for safety(incase of cable failure)

I'm not sure if you've fiddled with your TB yet, but it feels a lot like the TB is actuated by a geared motor acting against a spring (not a stepper!). It would probably be reasonably easy to rig something up...

Well, i'm off this weekend to try and mill myself out a manifold for the TBs, so i'll try and let you know how it goes

[Mike-F]

I was planing to build a slave throttle drive motor unit mounted to the bulk head with a shot cable linking to the TB's. I rekon the standard TB has a stepper motor and a feed back pot inside so planed to have the a stepper motor driving the cable with the feedback pot mounted on the TB's for safety(incase of cable failure)

I'm not sure if you've fiddled with your TB yet, but it feels a lot like the TB is actuated by a geared motor acting against a spring (not a stepper!). It would probably be reasonably easy to rig something up...

Well, i'm off this weekend to try and mill myself out a manifold for the TBs, so i'll try and let you know how it goes

No i have not had the TB of yet as i have only had the car about 6 weeks! So could be a servo drive with feed back, this would make sense as it wo uld be fail safe if power was lost to the TB This is why I really want to get hold of an old TB to rip apart( not really keen on pulling mine apart just yet! But may well get some bike TB's to start looking at a manifold design.