A friend called me up and his dad has an 850i and was wondering if anyone has bored out their throttle body/or if anyone knows someplace that can?

Thanks!

not worth the effort unless you go with extruded honed intakes, port and polished heads, and a different set of cams.

You can get away with up to 3mm's...

I agree the biggest choke point on the M70 is the intake manifold and the cams.
Think this between the 2 throttle bodies there is around 5" of butterfly.
Look at the throttle butterfly on the ls series engines theres not even close to 5"
and it still gets enough air for 400+ HP.
the cam only opens the valves 10.6MM at the valve .417 do a little cam studying .
compare that cam to aftermarket cams and you will see were the flaw lies.
Another thing i noticed.Seems like this motor was intensionaly made with alot of cam advance in mind to lower the torque curve as much as possible.

PM me

Think this between the 2 throttle bodies there is around 5" of butterfly.
Look at the throttle butterfly on the ls series engines theres not even close to 5"
and it still gets enough air for 400+ HP.


Keep in mind that a small increase in diameter of a single butterfly is a great increase in overall area, while two smaller butterflies do not necessarily equate.

An interesting note is that because the throttles do not open fully until 4200 rpm, an increase in butterfly size might effectively negate the amount of airflow blocked, giving you WOT airflow with the not fully opened throttle. This would be especially good for the turbo guys...

Keep in mind that a small increase in diameter of a single butterfly is a great increase in overall area, while two smaller butterflies do not necessarily equate.

An interesting note is that because the throttles do not open fully until 4200 rpm, an increase in butterfly size might effectively negate the amount of airflow blocked, giving you WOT airflow with the not fully opened throttle. This would be especially good for the turbo guys...

Get the Wokke V2 chip and you won't have to go through all the trouble.

A bit offtopic... but this intake talk made me think- would it be possible to put 2 throttlebodies on a single manifold? One on each end.

Get the Wokke V2 chip and you won't have to go through all the trouble.

I was commenting on this because I remember reading about John in DC having trouble making boost as early as he'd have liked because of this issue, unfortunately the Wokke V2 does not solve this problem for boosted cars.

A bit offtopic... but this intake talk made me think- would it be possible to put 2 throttlebodies on a single manifold? One on each end.

certainly possible, but likely not to net any gains. You would only have to build a simple voltage follower circuit out of a transistor in order to mimic the signal going to the original throttle without disturbing the voltage. You'd end up with twice the air at idle, so you'd have to add some circuitry to cut the supply voltage to the secondary throttle when the primary throttle sends an idle signal. Or maybe add a diode to drop the signal voltage enough so that at idle it's closed and at WOT the secondary throttle doesn't open fully.

Just thinking out loud

certainly possible, but likely not to net any gains. You would only have to build a simple voltage follower circuit out of a transistor in order to mimic the signal going to the original throttle without disturbing the voltage. You'd end up with twice the air at idle, so you'd have to add some circuitry to cut the supply voltage to the secondary throttle when the primary throttle sends an idle signal. Or maybe add a diode to drop the signal voltage enough so that at idle it's closed and at WOT the secondary throttle doesn't open fully.

Just thinking out loud

A resistor maybe instead of the diode but other brands already have two throttles on one intake manifold just on the sides instead of at each end.

http://img196.imageshack.us/img196/3902/800pxlamborghinimurciel.jpg (http://img196.imageshack.us/my.php?image=800pxlamborghinimurciel.jpg)

I was commenting on this because I remember reading about John in DC having trouble making boost as early as he'd have liked because of this issue, unfortunately the Wokke V2 does not solve this problem for boosted cars.



certainly possible, but likely not to net any gains. You would only have to build a simple voltage follower circuit out of a transistor in order to mimic the signal going to the original throttle without disturbing the voltage. You'd end up with twice the air at idle, so you'd have to add some circuitry to cut the supply voltage to the secondary throttle when the primary throttle sends an idle signal. Or maybe add a diode to drop the signal voltage enough so that at idle it's closed and at WOT the secondary throttle doesn't open fully.

Just thinking out loud

Original post was dealing with a plain-jane 850i (no-boost), therefore my answer still applies: V2 chip and done with the sluggish response.

As for TT cars - I believe Greg just posted that putting the V2 chip in his Dinan TT made a big difference and overcomes the associated "lag" a bit.

Original post was dealing with a plain-jane 850i (no-boost), therefore my answer still applies: V2 chip and done with the sluggish response.

As for TT cars - I believe Greg just posted that putting the V2 chip in his Dinan TT made a big difference and overcomes the associated "lag" a bit.

Gotcha, maybe watch what you're quoting next time then.

Nothing short of opening the throttle passage more would solve the slower than capable spool up time issue. No doubt that the wokke chip improves pedal to throttle response time, but what I'm talking about is on top of that. It's easy to visualize, just think about driving a boosted car at 75% vs. 100% throttle. It will take all the air it can get through the engine to spool up, so you want as little resistance to flow as possible on the compressor side.

In both cases the wokke chip applies here. Agreed......
I cant reason buying a biger door in sted of opening the door all the way

I agree the biggest choke point on the M70 is the intake manifold and the cams.
Think this between the 2 throttle bodies there is around 5" of butterfly.
Look at the throttle butterfly on the ls series engines theres not even close to 5"
and it still gets enough air for 400+ HP.
the cam only opens the valves 10.6MM at the valve .417 do a little cam studying .
compare that cam to aftermarket cams and you will see were the flaw lies.
Another thing i noticed.Seems like this motor was intensionaly made with alot of cam advance in mind to lower the torque curve as much as possible.

PM me
Wrong. The weak point is the exhaust PORT.

The other thing to think about is that the M70 biggest problem is NOT the throttle valve size or the manifolds, but very definetly the bad intake and exhaust port geometry on the heads. Short of forced induction you will not see much difference on a dyno even after opening the throttles, extrude-honing the manifolds and porting the heads. That route definetly does not give you enough improvement to be worth the effort. Enough folks tried that over the last 15 years.

Save your money:
1) Decent chipset - biggest bang for small bucks
2) forced-induction - biggest bang for the biggest bucks

EDIT--Looks like Auraraptor beat me to the punch line.

In both cases the wokke chip applies here. Agreed......
I cant reason buying a biger door in sted of opening the door all the way

Possibly you've been misled, the wokke chip does not open the throttle more than stock. What it does is allow the throttle to open to that point more quickly.

Wrong. The weak point is the exhaust PORT.

Yes the exhaust is probly not good enough but if it was the end all be all then the turbos wouldnt spool for sh.t. and nothing could save it.
I been playing around with the M70 i got a couple months ago and thats how i came to this conclusion.
The intake manifold runners are almost 20" long!!!
Major choke point suck on a 20" straw vs a 6" one and guess which flows better

Possibly you've been misled, the wokke chip does not open the throttle more than stock. What it does is allow the throttle to open to that point more quickly.
Id ask Wokke first insted of speaking for him, to see if its tru.
Hands down the CHIP is the best bang for the buck no question

If you don't like how smooth your V12 is, Cut those runners to 6 inches and see how you like it, Just a note and not a bash, Everything that works to gain from the M70 has been tried already unless your successful with redesigning the heads, It's the main shutout from making it as powerful as it is reliable.

Yes the exhaust is probly not good enough but if it was the end all be all then the turbos wouldnt spool for sh.t. and nothing could save it.
I been playing around with the M70 i got a couple months ago and thats how i came to this conclusion.
The intake manifold runners are almost 20" long!!!
Major choke point suck on a 20" straw vs a 6" one and guess which flows better

The probable reason that the intakes are so long is for velocity not volume because the longer intake runners force the air to tumble for a better mix and thus more torque.

As a reference, Audi uses two or three stage intake manifolds to make the runner path longer or shorter based on engine rpm and the longer path is for low range rpm torque.

So since the M70 is a very torquey engine and it red lines at only 6K rpms it should need more velocity from the longer runners.

Who's still red line @ 6?---)

Lag.. what lag??

Yes the exhaust is probly not good enough but if it was the end all be all then the turbos wouldnt spool for sh.t. and nothing could save it.
I been playing around with the M70 i got a couple months ago and thats how i came to this conclusion.
The intake manifold runners are almost 20" long!!!
Major choke point suck on a 20" straw vs a 6" one and guess which flows better


Id ask Wokke first insted of speaking for him, to see if its tru.
Hands down the CHIP is the best bang for the buck no question

I have taken apart the V12 as well. I still have 1 and half engines in my garage.

I flow tested the heads. It is the major point. The headers are long, but not as big a problem...confirmed by the HP made by the V12 individual TB conversion.

If there was a chance for more power i wonder if people would be willing to sacifice the idle quality/smoothness?

I have taken apart the V12 as well. I still have 1 and half engines in my garage.

I flow tested the heads. It is the major point. The headers are long, but not as big a problem...confirmed by the HP made by the V12 individual TB conversion.

If you have the cfm ### can i see them it would save me some trouble...Before anymods of course

If there was a chance for more power i wonder if people would be willing to sacifice the idle quality/smoothness?Absolulety, It's been done, I haven't seen it in a E31 though! You can see on the TT engine how the runners have been cut a lot and was cut slightly more for the project at hand, Worked out great, I've seen the M70 inside of a volvo, Nissan 240Z, Datsun 510 and a few other cars with a totally differnt fuel management system, The 240z has Velocity Stacks, The best sounding Nissan i've ever heard, These cars didn't sound stock because they were not, But ran and idle great.

Get the Wokke V2 chip and you won't have to go through all the trouble.

Yeah! +1 with that! http://www.picturehoster.org/storage/411.jpg

8EIGHTS dont hold out on us post all the moded M70,s you got...
Plzzzzzzzz
Maybe a new thread start with theones you posted here.

Id ask Wokke first insted of speaking for him, to see if its

Info came from wokke actually in a thread here a couple days ago

8EIGHTS dont hold out on us post all the moded M70,s you got...
Plzzzzzzzz
Maybe a new thread start with theones you posted here.Got your nerves with all your TOP SECRETS? This set up is not E31 related, It's in a sand rail and will be kicking dirt memorial weekend, Taking it to Vegas for some stress relief.

Noooo im not one of them "Not E31 related" guys....
we shouldnt even be putting up with that sounds like a disclaimer.
:(
If its car related im all for it.
You know i love to post more but i always get crap for it, especially if it goes against the norm.

I'm not saying your not Alex, I'm saying the engine is in a home made Sand rail, A dune buggy, Sorry for the misunderstanding.

I'm not saying your not Alex, I'm saying the engine is in a home made Sand rail, A dune buggy, Sorry for the misunderstanding.

is this one of the ones built in SD by ..... (seems I've forgotten his name :help)

A friend called me up and his dad has an 850i and was wondering if anyone has bored out their throttle body/or if anyone knows someplace that can?

Thanks!

I had mine done for the 860 but Tx is right. may not yield you much without associated head and cam work. I also switched to the E36 MAF (with proper programming) to accommodate the airflow.

http://members.roadfly.com/faisal_in_laurel/VCV/VCV07.jpg

http://members.roadfly.com/faisal_in_laurel/VCV/VCV02.jpg

I had mine done for the 860 but Tx is right. may not yield you much without associated head and cam work. I also switched to the E36 MAF (with proper programming) to accommodate the airflow.

http://members.roadfly.com/faisal_in_laurel/VCV/VCV07.jpg

http://members.roadfly.com/faisal_in_laurel/VCV/VCV02.jpg
What other changes did you have to do for Hal9000 to play nice?