engine and drivetrain EFI throttle body (esp. Zenon)

[cowlum]

I have been recently been collecting the parts to switch to efi recently..

I have purchased some slightly larger injectors (about 10%).

I have failed to find a decent throttle body in the last month, so I figured I might just go with the original 318 TB.. its robust and needs no fabrication.

Zenon you switched to the original 318 TB when your 5.0 mustang TB died. Did you notice much difference??

Basically. Will the 318 TB be the bottle neck for my stock 2002 engine? + switching to a larger TB in future wouldnt be so hard would it?

[Guest Anonymous]

switching to a larger TB later won't be that hard. It's as easy as bolting it up to the bottom of the intake manifold.

No idea about the difference in performance between the mustang 5.0 & 318 TB, do the math, what's the difference in MM between the two?

[cowlum]

I think it 45mm vs 50mm..

how is the math done?

[Zenon]

Zenon you switched to the original 318 TB when your 5.0 mustang TB died. Did you notice much difference??

Basically. Will the 318 TB be the bottle neck for my stock 2002 engine? + switching to a larger TB in future wouldnt be so hard would it?

I didn't notice a big difference in the manifold pressure readings at WOT/redline, but then the size difference was not that big. The ford TB (from an unknown app, not necessarily a mustang) I had was only about 50mm, the 318i is about 45mm. Perhaps my intake is restrictive in general since I read ~95KPa when atmospheric is 98KPa. Under 5000RPM, this is no longer an issue, though, so I don't worry too much about it since it is a street car. An ideal intake would show full atmospheric pressure in the manifold at WOT/redline.

I did notice a change in throttle response but that has to do with the linkage. The BMW part has a very progressive compound linkage and is designed so that throttle movement is very small relative to pedal movement just off idle. The ford part had more zip off the line but not much else for the remaining 70% of pedal range. The ford part was more fun but the more progressive (if less exciting) setup makes the car far more driveable in traffic. Also, if all else is equal, the bigger the TB the more touchy the off-idle and low-rpm part throttle control will be anyway.

If I can find one that fits well and has suitable cable linkage (progressive with a workable direction of pull, etc) I would still like to try a TB around 60mm.

I'd say just get the TB size you really want to use first and make the adapter, cable brackets etc when it is all out of the car. It is much harder to work upside down in cramped quarters and I found just removing the ford TB, reinstalling the 318i TB, and especially reworking the cable bracket was not easy. With that experience in mind, I'll get another 318i intake manifold to model/mock-up with with before I try to change my present setup. BTW, beware clearances to the brake booster and starter motor.

regards,

Zenon

[colorobo2002]

That would be the TB for my daily driver.

[slash02]

I have been recently been collecting the parts to switch to efi recently..

I have purchased some slightly larger injectors (about 10%).

I have failed to find a decent throttle body in the last month, so I figured I might just go with the original 318 TB.. its robust and needs no fabrication.

Zenon you switched to the original 318 TB when your 5.0 mustang TB died. Did you notice much difference??

Basically. Will the 318 TB be the bottle neck for my stock 2002 engine? + switching to a larger TB in future wouldnt be so hard would it?

318i TB will probably be fine. It seems to look alot smallet then the Tii TB. I will be using an M30 TB on my setup. Probably too big lol.

Zenon, what did you use for TPS?

[Zenon]

Zenon, what did you use for TPS?

I am presently using the original 318i throttle position switch. I wired it as a voltage divider with two 10K resistors so that it would work with the Megasquirt's analog throttle position input. Thus, idle reads as 0, WOT as 255, and anywhere in between as 128.

I'm using the MAP-based accel enrichment feature of the MSnS-Extra firmware so the TPS is only needed for the deceleration fuel cut and flood clear features. I have not noticed any downside to this setup compared to when I had a potentiometer style TPS on the Ford TB, other than the datalogs are now slightly less useful since the exact physical throttle position is no longer displayed.

regards,

Zenon

[slash02]

Zenon, what did you use for TPS?

I am presently using the original 318i throttle position switch. I wired it as a voltage divider with two 10K resistors so that it would work with the Megasquirt's analog throttle position input. Thus, idle reads as 0, WOT as 255, and anywhere in between as 128.

I'm using the MAP-based accel enrichment feature of the MSnS-Extra firmware so the TPS is only needed for the deceleration fuel cut and flood clear features. I have not noticed any downside to this setup compared to when I had a potentiometer style TPS on the Ford TB, other than the datalogs are now slightly less useful since the exact physical throttle position is no longer displayed.

regards,

Zenon

Ok, seems there's a volvo TPS that fits, bolts right up, that's why i asked. Or a Saab one.. It never occured to me to do that, would be a quick way to get a "tps" in a pinch...

I'm still trying to figgure out model and year of saab/volvo so I can make my order...

[canadamatt]

Just another vote for map-based, I'm not running a TPS on mine either, works slick rick. Less parts to buy, less parts to make, and most importantly, less parts to break

No wait, the most important thing is that you have more beer money left over...

Matt