Throttle body question

[serdar255]

I've been eyeing a BBTB for sometime now and wanted to know if anyone owns one. If you do have you noticed a difference in throttle response or seat of the pants power. IF it makes a difference my car has a chip, catback, lightweight flywheel, and I'm considering long tube headers.

At $100 after sending a core, it is pretty tempting.

Here's the link to the throttle body:

http://www.westcoastriots.com/

Thanks :D

[digger]

I've been eyeing a BBTB for sometime now and wanted to know if anyone owns one. If you do have you noticed a difference in throttle response or seat of the pants power. IF it makes a difference my car has a chip, catback, lightweight flywheel, and I'm considering long tube headers.

At $100 after sending a core, it is pretty tempting.

Here's the link to the throttle body:

http://www.westcoastriots.com/

Thanks :D

i have a BBTB. it will be a little more responsive because with a given angular input there is more flow area presented but thats probably about it. i cant say i remember noticing more power so if there is it would likely be small.

why do you do a before and after test on a dyno or something?

[Bearmw]

Not sure if a BBTB will help your engine but I went with Maxbore and the price and quality was good. You may want to research what kind of CFM you need from the TB and do some testing with a good vacuum before spending extra money.

[whodwho]

...

At $100 after sending a core, it is pretty tempting.

Here's the link to the throttle body:

http://www.westcoastriots.com/

...

FYI, it is 200 + core ;)

[serdar255]

FYI, it is 200 + core ;)

Damn i didn't notice that. Thanks for pointing that out.

[jlevie]

Pretty much a waste of money. The mass flow restriction on an M20 is the head. Nothing you do before or after that will have a significant affect.

[digger]

Pretty much a waste of money. The mass flow restriction on an M20 is the head. Nothing you do before or after that will have a significant affect.

wrong, get rid of the cast manifold and induction system and replace with an ITB system there are decent gains with stock head and camshaft.
have seen a good exhaust system make a huge difference with stock head and camshaft

[jlevie]

A free flow exhaust, yes. The stock exhaust is a compromise between performance and street use. ITB's will improve throttle response and will positively affect part of the power range, but negatively affect the rest. The limit in mass flow, regardless of the cam, is the head. Later engines address that by using more than two valves per cylinder.

[mpowerful]

:popcorn:

[digger]

A free flow exhaust, yes. The stock exhaust is a compromise between performance and street use. ITB's will improve throttle response and will positively affect part of the power range, but negatively affect the rest. The limit in mass flow, regardless of the cam, is the head. Later engines address that by using more than two valves per cylinder.

no negative effects from using an ITB with the correct size TB, runner diameter and length this is proven on e30tech on a stock b25.

there is enough headflow to make 250bhp with a stock head with appropriate cam and mods to suit. a massaged head can bump that up to 320-330bhp on pump fuel also proven on e30tech.

[jlevie]

You aren't going to make 250hp on a naturally aspirated M20 engine. And once you go to FI head restrictions aren't as important. Just crank up the boost to get the mass flow into the cylinders.

[digger]

You aren't going to make 250hp on a naturally aspirated M20 engine. And once you go to FI head restrictions aren't as important. Just crank up the boost to get the mass flow into the cylinders.

lol there is enough flow to support it with ease, there are a couple of builds on e30tech with 290whp and 350whp (modified heads).

most do light massaging when they do a half decent build so the data is not great on a untouched head (most port jobs probably are no better than stock anyway and there are heaps of 200whp+ m20 these days) it is so easy to improve things when you know what to do that it is madness to not do it.

[essi1553]

:popcorn:

[evobmwe30]

What is the stock bore on the m20 1990 throttle body? Also will any other throttle body's fit on the stock manifold

[digger]

What is the stock bore on the m20 1990 throttle body? Also will any other throttle body's fit on the stock manifold

stock b25 60 mm bore IIRC at the throttle plate, entry to the body is like 63 or 64 mm so it tapers down. probably the 323i and 325e throttles bolt up if you want something smaller lol. pretty much have it bored out to 63mm and put in a new plate often from an M30.

at one point i was contemplating using a M30 BBTB like 65mm or 66mm with adapter for the different mounting bolt pattern but lost interest with playing around with the mechanism.

the cast fannymold is more a restriction than a straight short bit of pipe better off focusing on it if you want to do something bolt on that is worthwhile