Throttle bodies, six in fact

[Greg111 13]

I had the plenum off the 3 last week to tidy a few thingys up, cleaned and metal polished the throttle bodies for that "wank" factor and basically shiny'd up every thing else, so anyway what i noticed with the throttle bodies is the fact that on full throttle they were only opening 3/4 due to the throttle stop bolt. I put it on the diag at work and the potentiometer was reading 76% on full throttle, naturally i wound the bolt down so it read 100%, turns out for three years of ownership it was running as a 330 not an M3 because now it goes like an absolute cut cat!

What i want to know is why was that bolt wound up (factory?) if anyone including Glenn please could explain?

Our BMW master tech of 25 years was stumped.

I said throttle lots.

[*Glenn* 854]

It's realy been serviced well since 1995 hasn't it ??. I bet it's had driveabilty issues before and its never been checked

[Greg111 13]

It's realy been serviced well since 1995 hasn't it ??. I bet it's had driveabilty issues before and its never been checked

Don't know about before i owned it but it's never missed a beat engine wise whilst its been in my hands, the reason i brought this up is we had another E36 M3 come in the day after and the throttle bolt was also wound up the same amount so assumed this was factory but why??? As long as the AFM is working correctly i can't see this being an issue having 100% open?

[westy 614]

Maybe the bolts just have a tendency to back out????

[Greg111 13]

Maybe the bolts just have a tendency to back out????

That could be a possibility but they have a lock nut holding it down also, i can provide a pic to explain better than words.

[DRTDVL 0]

yes please to pic

[westy 614]

Imagining a bolt through a nut through a steel tab? Usually bulletproof.

Strange to find two.

Posting for real reason at all.

[*Glenn* 854]

I'm at home now...whats the correct setting in TIS ??

[hybrid 1043]

That could be a possibility but they have a lock nut holding it down also, i can provide a pic to explain better than words.

want me to have a look at mine when I get home ?

[CamB 48]

I had a look a mine - its a bolt threaded down to the correct* height and a nut that's used to tighten it in place.

* mine's correct - you can see the throttle plates are moving 90 deg. Of course I checked by myself so I don't know if full pedal travel gives full throttle at the TBs.

[hybrid 1043]

I had a look a mine - its a bolt threaded down to the correct* height and a nut that's used to tighten it in place.

* mine's correct - you can see the throttle plates are moving 90 deg. Of course I checked by myself so I don't know if full pedal travel gives full throttle at the TBs.

When I set mine and tuned the throttle cable I had brendon press the throttle pedal and I waited for the 'click' of the brass butterflies to hit full open and dailed it back half a thread as not to cause the cable to stretch.

[BM WORLD 1283]

hhhmmm funny , when reasembling the M88 m5 engine back into the e28 i noticed also the throttle valves also not going fully open , same type of system with a locked bolt etc . so adjusted so it does now .

and thats on a 25 year old engine

[Michael. 2313]

What an intriguing revelation..... Good discovery!

Reminds me of a friend of mine who discovered someone had put small port exhaust manifold gaskets on with large primary headers, creating a restriction of the exhaust gases. It performed noticeably better with the correct gaskets in places. (On a Ford 302)

[Greg111 13]

I'm at home now...whats the correct setting in TIS ??

That's one thing i forgot to look at, that will have the correct adjustment.

I had a look a mine - its a bolt threaded down to the correct* height and a nut that's used to tighten it in place.

* mine's correct - you can see the throttle plates are moving 90 deg. Of course I checked by myself so I don't know if full pedal travel gives full throttle at the TBs.

Mine definitely was not moving 90 degrees.

When I set mine and tuned the throttle cable I had brendon press the throttle pedal and I waited for the 'click' of the brass butterflies to hit full open and dailed it back half a thread as not to cause the cable to stretch.

The butterflies weren't making that noise until i adjusted them, now when you go full throttle they make that clicking noise.

hhhmmm funny , when reasembling the M88 m5 engine back into the e28 i noticed also the throttle valves also not going fully open , same type of system with a locked bolt etc . so adjusted so it does now .

and thats on a 25 year old engine

So the M5s are the same, just seems funny that i've found two S50s like this, almost like that's how they were from factory? On the open road it's so much more noticeable.

As i mentioned, i can't see this hurting the engine in anyway as long as the AFM is working correctly.