efi throttle linkage?

[Guest Anonymous]

What are you m2/m20/megasquirt guys doing for throttle linkages? I've seen zenons, everyone doing similar? What are you using for short cables, bicycle shop?

If anyone has pics, please post. I'm sick of the 1:1 pull cable . Plan to have this done by tommorow morning to keep me 'on schedule'

Matt

[JohnN]

pedal perfectly and has a swivel attachment to connect it to your TB. Either stainless or black sheath for the cable. Available through Summit Racing or most other supplier.

John N

[canadamatt]

Yes, but that doesn't help for the 1:1 pull. Driving my m20 with the 1:1 cable is like an on/off switch for the gas, its takes a while to get used to the feel. Anyone else who drives the car usually launches it through a wall for the first few starts . Basically I'm wondering how people accomplished the 'lever' pull to slow it down. I'm assuming just a variation of what Zenon did..

as per Zenon

http://www.zeebuck.com/bimmers/tech/Megasquirt/preparation.html

So are most people just using a straight 1:1 cable?

Matt

[Inka]

So are most people just using a straight 1:1 cable?

I'm using a 1:1 cable and, as you can imagine, it makes driving the car tough. I appreciate Zenon's solution, but I'd prefer for it to be less visible. I wonder if something similar could be done closer to the throttle pedal or incorporate it with the throttle mechanism?

Looking forward to watching this discussion...

Robert

[Pinepig]

Why not just drill a new hole in the throttle arm to get less travel for the same abount of pedal movement.

I'll be collecting parts for the MS swap this next week and I'm going to try.

I'll be sure and document the process for you guys.

[jimk]

I use a 1:1 on a cable on 45mm TWM ITBs. Don't be afraid of launching anything. The EFI pulls much stronger off idle than the carb, but you don't have to rev it to pull away. The carb hesittion is completely gone! And you can almost let out the clutch without hardly any throttle.

It took quite a while for me to get used to not having any lurch. All the work to reduce the ratio is unfounded. I've been using mine for over 2 years now.

[jimk]

I use a 1:1 on a cable on 45mm TWM ITBs. Don't be afraid of launching anything. The EFI pulls much stronger off idle than the carb, but you don't have to rev it to pull away. The carb hesittion is completely gone! And you can almost let out the clutch without hardly any throttle.

It took quite a while for me to get used to not having any lurch. All the work to reduce the ratio is unfounded. I've been using mine for over 2 years now.

[canadamatt]

Well, I wouldn't say its 'unfounded'. I've had the m20 in for what, 4 years now? I'm totally 'used' to it, but that doesn't mean I like it! .

I'll let you know how it turns out...deadline for finishing is tommorow at the first beer break (thats usually around 10am however.. )

Matt

[Zenon]

Matt,

JimK still has a boner for me from way back - Zenon did it, therefore it must be dissed. What-everrrr.

BTW, I stole that linkage idea from Larry Harris who was one of the first people I had ever seen with a home-made '02 EFI setup - he even designed and built his own ECU totally from scratch. His site seems to be long gone, though. Seemed like a clever guy, so why not poach his tech?

As pinepig pointed out, there is no particular reason you can't attach the cable closer to the pivot in the lower throttle lever to get a more progressive throttle action with a direct pull - geometrically it is the same thing as what my setup does. I did it the way I did because I thought it was slick to keep the original vertical rod and threaded end and it made it easier to have a proper return spring (added after that pic). It also made it easier to make fine adjustments (so I could use 100% of the available pedal range without anything being strained). I also imagine it keeps the open end of the cable cleaner. So far so good and well worth the effort - for me, at least.

regards,

Zenon

[jimk]

Zenon,

I have no problems with a reduced ratio. Just 1:1 is what I have and I have no dissatifaction with it. I believe the misconception is with the 1:1 ratio is with carbs experience where the carb needs some throttle opening to get away from idle to keep the fuel flow from stalling, it is hard to get away without a surge. Where as with efi the fuel is regulated by what the map sensor reads at any given set of other conditions, like rpm, coolant temp, etc. and it will pull away smoothly.

[JohnN]

Zenon,

I have no problems with a reduced ratio. Just 1:1 is what I have and I have no dissatifaction with it. I believe the misconception is with the 1:1 ratio is with carbs experience where the carb needs some throttle opening to get away from idle to keep the fuel flow from stalling, it is hard to get away without a surge. Where as with efi the fuel is regulated by what the map sensor reads at any given set of other conditions, like rpm, coolant temp, etc. and it will pull away smoothly.

I've been running EFI (M10) now for over three years. I use the Lokar cable and pop rivited a "L" shaped bracket to the firewall to hold the pedal end of the cable. It runs 1:1 to a 733 throttle body and I have absolutely no problem with throttle tip-in. The GGCBMWCCA chapter requires double springs on the throttle linkage if you're going to take the car to a driver's school, so I even added an extra return spring. The throttle opens smoothly and evenly. Based on my experience I think you have a cable binding problem and would suggest before you do anything too fancy, try replacing the bicycle cable.

Regards,

John N

[Harv]

I hate to say it but a true 1:1 ratio is very hard to get. You would have to make sure the cable and pull are at the same position on the throttle body and the gas pedal. Many manufactures use round pulls (or cam shaped pulleys) so that the pull ratio stays the same over the whole ratio. My friend with TWM 45's on a B2.3 powered 142 volvo had a hard time getting the TB's to open slow enough to make driving smooth. It was hard to modulate the first 1/4 of movement. Moving the position of the cable in relation to the pulls helps a lot.

Make any sense?

John

[Inka]

Moving the position of the cable in relation to the pulls helps a lot.

Can you elaborate on that?

Thanks,

Robert

[Harv]

Moving the position of the cable in relation to the pulls helps a lot.

Can you elaborate on that?

Thanks,

Robert

Yea.

Imagine the cable comming out of the housing and going to what ever arm that pulls it (assuming the arm is mounted to something that turns like the gas pedel) If the arm is perpendicular to the cable, that would be the highest rate of pull since everything after that would be at an angle due to the rotation of the arm. ( I wish I could draw on this thing to show you what I mean)

John