E30 Zone

Hi all ive decided that im to keep the e30 325i engine but add throttle bodies on the current engine. As it is the heart and soul of the E30 and dont really want to replace it and am prepared to start modding. Does anybody know any multi throttle bodies that would fit the bmw e30 325i engine? i know dblias do one but that is just too much financially does anyone know whether the e36 / e46 carberettors will fit the e30 with certain adaptor plates?? hel[p plzz gonna get started on this to get it ready for the show season 2012

Im fairly sure e36 M3 throttles would fit with an adaptor plate, I have a set and thery're not a million miles different.
What are you going to do about fueling and mapping / ecu side of things?

i have no idea fella my theory is if theres a will there is a way u fancy selling your set fella?? and would you know any comapnies to get the adaptor plates from?? if you dont wish to sell you ones?? ecu remap perhaps ??? no idea into the mapping side of things just doing my research at the moment fella

http://www.extrudabody.com/servlet/the- ... ith/Detail

The company above are selling ITB with plug and play ECU.

damn thats expensive thanks for the info lion now thats another comapny that do kits i knwo of anyone know where i can get adaptor plates from to fit e36 m3 webers on? and other tings i need for the transformation thank in advance

ive seen a few forums with a similar thread there must be a few companies which sell adaptor plates to bolt e36 m3 carbs or s50 carbs on a m20 engine??? anyone know or heard of such companies????

aarc wrote:ive seen a few forums with a similar thread there must be a few companies which sell adaptor plates to bolt e36 m3 carbs or s50 carbs on a m20 engine??? anyone know or heard of such companies????

I think you're talking about ITBs (individual (or injection) throttle bodies) not carbs. The E36 M3 has the S50 engine, so you're talking about the same thing. Webers are carbs, not ITBs and were not fitted to the E36 M3.

From what I've read and been told, ITBs on an M20 are a bit pointless unless you have some serious internal engine work or the car will see track action. The power and torque they do produce is high up the rev range, meaning they don't make for nice to drive cars on the road.
The E36 M3 had the Vanos system so it could produce low down torque and then change the valve timing to make use of the ITBs.

Coupled with a 2.7/2.8 built M20, a decent 6 branch, cam, remap and possibly head work, I expect ITBs might be a bit more worthwhile, but not so much on a mildly tuned 2.5.

I remember a seriously built 2.8 M20 on here with ITBs making about 250bhp, but it it cost big to get there

Well im not sure if the stock ECU has the capability to monitor the fueling and allowances for adjusted airflow, you would probably be best on VEMS or some such as the linked above option would be out of my price range.
What other supporting mods do you have or plan to get? Im not 100% convinced the gains from this would be worth the cost, vs. something like a MAF conversion on a stock 2.5 engine.

I may sell my ITB's and I do know a company in sussex that could make the adaptor plate but im not sure if I want to keep them for myself .

You can pick a set of e36 m3 throttles up on egay for about £300 (with injectors if you are lucky).

hi all sorry JMC for my terminology yes your spot on ITB's i have seen a few threads on these conversions in your opinion would your know whether its the e46 m3 itbs i need to go for??

s13B you have pm

What budget do you have in mind for this conversion?

I'm sure a zoner had some adaptors made last year for the S50 ITB's, can't remember who, but there was a picture of them on here somewhere.

I think you're right Rav, but I can't use the search function while on my phone so can't look for it.

I've never seen anyone use the E46 S54 ITBs.
Infact, I don't recall anyone actually finishing a homebrew ITB conversion on an M20, probably down to cost and the minimal gains to be had from a mildly tuned engine.

you'd never be able to modify an M20 to properly make use of 45mm throttles the head cant be made to flow enough because of the bore limiting the valve sizes, let alone throttles from an S50 or S54 it would kill the midrange massively and no added topend. every single dyno plot of a dbilas system has no midrange at all it is a cosmetic mod.............stick to bike throttles 35 to 40mm max for a stroker

Another reason that S5? ITB's don't find their way onto M20's is that the port on the M20 is a circular shape cut at an angle which makes a tall rectangular shape, whilst the S50 ITB's have a flat rectangular shape. So any amount of grinding or adapter flange is not going to make the geometry align.


If you want to tune a M20 keep the intake manifold, but use all the tricks to get it breathing better, like BBTB, gas flowed cylilnderhead, maf conversion, etc. Oversize valves if you're a big spender. And then get it a stroker kit, 2,8 crank from a M52. It seems like the least trouble for small money. The old 2,7 conversions that was done by Alpina etc. all required special pistons, and today people mill of the block to get the compression up, all expensive solutions that make you dependent on special parts, with the 2,8 crank, the rest is standard parts. The zones wiki page describes how to do it.

ITB's on an M20 just don't work, or knowone has bothered to do it properly with small enough TB's. From what I've seen 35mm is for a fully modified engine. A stockish 2.7/2.8 would only warrant 30mm for a road vehicle.

The M20 is a very well balanced engine in terms of overall tune, there's no one aspect that you can change that will really set the world on fire. Having siad that if you could only change one part then the BTB exhaust manifolds would be the money no object part of choice.

Hi all im currently thinking to but the following ITB kit for my e30 m20 engine just hav a breif question if i were to buy this kit would it be possible to remap the current ECU in the car or would you recommend to buy the ecu from Extrudabody themselves well thats like 1000

I see many people stating that it's just not worth it to build an ITB rig for an M20 unless it's heavily modified, but at the same time you admit that not many have really fully gone through the exercise of building a home brew rig and taking it to the dyno to see what it will do. I’ve seen a few rigs out there, but very little in terms of detailed build threads showing before and after dyno runs.

For what it’s worth, a mate of mine recently built an ITB set-up for his 318is using 42mm throttle bodies (he has a bone stock motor). After installing the rig the readings on his wideband O2 sensor were lean across the board. He couldn’t even go WOT because the mixture would go dangerously lean. That means he is getting substantially more air into the motor than he was before with the stock intake. He’s still in the process of dyno tuning, but based on how lean his AFRs were I’d guess he’ll be able to easily get 15-20whp on the top end, which is pretty substantial for a stock M42. I’m not sure how or if his torque is going to suffer yet, but the important thing is that he is going through the exercise and learning what works and what doesn’t.

If you’re tight on cash and looking for some guaranteed gains, yeah this might not be the route to go. However if you can afford it I say go for it. I know I’m going to give it a shot this winter

Bullet_ride go for it with the M20. The motronic can be modified to go alpha-N instead of using the AFM.

The M42 bears no resmblance to the M20 other than stock bore size and really isn't good grounds that your idea will work, when lets face it, noone has succesfully made a kit that works.

I went to a dyno session with a guy called Dave on here, he had an alpina 2.7 bottom end and big ITB's, the biggest issue with his setup was the fact the inlet was drawing hot air from the engine bay, just another in a very long list of issues to resolve fitting ITB's to an M20.

When you can drop in a 6 cylinder M3 engine if you want ITB's it's not worth the time / effort / money gettting ITB's onto an M20 which will then need a massive ammount of time on a dyno mapping it.

e301988325i wrote:Bullet_ride go for it with the M20. The motronic can be modified to go alpha-N instead of using the AFM.

When you can drop in a 6 cylinder M3 engine if you want ITB's it's not worth the time / effort / money gettting ITB's onto an M20 which will then need a massive ammount of time on a dyno mapping it.

My car is already running on a DIY stand alone kit. Switching over to alpha-N is just a few mouse clicks away

I'm going to build a set to go on my 2.8L M20. I've already got a set of long tube headers and a schrick 284 cam in the head. I just need to find someone not too far away from me who can do some legitimate head work (flow bench verified). I'll definitely make sure to do a base line dyno with stock intake, ITBs with no head work dyno, and ITBs + headwork dyno.

Bullet_Ride wrote:I see many people stating that it's just not worth it to build an ITB rig for an M20 unless it's heavily modified, but at the same time you admit that not many have really fully gone through the exercise of building a home brew rig and taking it to the dyno to see what it will do.

It has been done on a 2.5 by a few specialists and found that the power/torque is too far up the rev range, so unless you want to scream the nuts off the engine, its not going to be much use on a road going car...

Bullet_Ride wrote: I'm going to build a set to go on my 2.8L M20. I've already got a set of long tube headers and a schrick 284 cam in the head.

On a decent built 2.8 however, I would think the low down torque will make up for the loss of fitting the ITBs, so definitely get on and bring the before and after results

Definitely no sock filters though , make a decent airbox/plenum to make the best of it

just a thought, someone mentioned about mounting the ITB's well are we forgetting about turbo_brown (alex?)?? In his sig was a link to the blueprints for manifold to mount the ITB's on.

i'm sure i've got it saved on my laptop some where so I might print it off & have a word with a few local engineering shops I know of & see how much the would charge to knock it up.

also someone else (might even be the same person lol) said that 38mm ITB'S would be to big well i'm sure that the like's of a honda cbr600 or a bandit 400 have ITB'S that are about 30 - 32mm, would these be the right size?? Just a thought really.

The M20 on TB's can be made to provide a very nice torque curve. Yes peak power is at ~6600rpm but the torque is very smooth.

Below are from my E21 Racer with a 2.7 and a std HC 2.5 both running with a 282 Schrick and Dbilas TB's (~45mm) and their inlet plenum. Emerald Standalone mapped by Dave Walker.



Dbilas and engines were sold as I've got the S54 in there now.

Duracel79

duracel79 wrote:The M20 on TB's can be made to provide a very nice torque curve. Yes peak power is at ~6600rpm but the torque is very smooth.

Below are from my E21 Racer with a 2.7 and a std HC 2.5 both running with a 282 Schrick and Dbilas TB's (~45mm) and their inlet plenum. Emerald Standalone mapped by Dave Walker.

Do you happen to have a dyno plot of the same motors but with the stock intake manifold?

No, only a comparison to the S54 on Standalone

Bullet_Ride wrote:
For what it’s worth, a mate of mine recently built an ITB set-up for his 318is using 42mm throttle bodies (he has a bone stock motor). After installing the rig the readings on his wideband O2 sensor were lean across the board. He couldn’t even go WOT because the mixture would go dangerously lean. That means he is getting substantially more air into the motor than he was before with the stock intake. He’s still in the process of dyno tuning, but based on how lean his AFRs were I’d guess he’ll be able to easily get 15-20whp on the top end, which is pretty substantial for a stock M42. I’m not sure how or if his torque is going to suffer yet

I guess it will scream at the top end, but the low and mid range will suffer. There could be an improvement over the stock M42 low/mid range, but he might see bigger gains with smaller throttles, although that means the top end will suffer which is the trade off.
I'm not completely up with throttle sizing, but I'd think 42mm will be too big for an 1800cc - if like the S50, the M42 had Vanos to allow good low/mid range but then change to make use of the big throttles, they may well work, but as it doesn't I wouldn't be going over 38-40mm and even that's probably too big for a road car.

The guys in the US don't see massive gains when fitting ITBs (usually Euro S50 ITBs) to the M42 from what I've read.

I can remember a mate with a 2.0 16v Nova, fitted with twin 40 carbs. He changed to 45mm ITBs, yes it went like hell, but only when nearing the limiter - it did spend most of time there and soon a rod made a successful bid to escape the block

duracel79 wrote:The M20 on TB's can be made to provide a very nice torque curve. Yes peak power is at ~6600rpm but the torque is very smooth.

Below are from my E21 Racer with a 2.7 and a std HC 2.5 both running with a 282 Schrick and Dbilas TB's (~45mm) and their inlet plenum. Emerald Standalone mapped by Dave Walker.



Dbilas and engines were sold as I've got the S54 in there now.

Duracel79

you can see the torque loss in midrange by looking at the magnitude and shape, the standard B25 makes 170lbft. you lose the bump in torque that the standard one delivers from about 3500rpm upwards. if the kit used 35-38mm it would be alot better

I'm using 44mm throttle because I was able to get 6 for about half the price it would have cost me to buy 40mm throttles. I'm going to build my ITB set-up in such a way that it shouldn't be hard to change over to smaller throttles if the 44s really prove to be that bad. If someone wants to donate a set of 35-38mm throttles to me I'll gladly dyno test both

reggid wrote:you can see the torque loss in midrange by looking at the magnitude and shape, the standard B25 makes 170lbft. you lose the bump in torque that the standard one delivers from about 3500rpm upwards. if the kit used 35-38mm it would be alot better

I couldn't be bothere to point that out, talk about own goal.

Ps) A good 2.7 build like that one should be making 190lb/ft!!!!!

Here's a set for sale.



Found here

http://www.r3vlimited.com/board/showthread.php?t=266709

reggid wrote:

duracel79 wrote:The M20 on TB's can be made to provide a very nice torque curve. Yes peak power is at ~6600rpm but the torque is very smooth.

Below are from my E21 Racer with a 2.7 and a std HC 2.5 both running with a 282 Schrick and Dbilas TB's (~45mm) and their inlet plenum. Emerald Standalone mapped by Dave Walker.



Dbilas and engines were sold as I've got the S54 in there now.

Duracel79

you can see the torque loss in midrange by looking at the magnitude and shape, the standard B25 makes 170lbft. you lose the bump in torque that the standard one delivers from about 3500rpm upwards. if the kit used 35-38mm it would be alot better

Different Rolling roads will give different figures. Same car two weeks later made over 195lbft at Evolve in Luton. On screen they showed me my trace against a std C2 2.7 Alpina. Torque curves matched up to 4500rpm then this rose away from the C2. No printout of it though.

e301988325i wrote:

reggid wrote:you can see the torque loss in midrange by looking at the magnitude and shape, the standard B25 makes 170lbft. you lose the bump in torque that the standard one delivers from about 3500rpm upwards. if the kit used 35-38mm it would be alot better

I couldn't be bothere to point that out, talk about own goal.

Ps) A good 2.7 build like that one should be making 190lb/ft!!!!!

Heres the other run at Evolve, make of it what you will

should be making more torque and hp with that setup a high CR 2.7L with 280+ cam, i would bet money that upto 5500rpm the stock intake manifold would make more hp/torque. you need a bigger cam to best utilse the dbilas size and volume to see worthwhile gains over the stock one. i would use a 296 enem or schrick 304 with ITB and standalone the ITB will improve drievability over the stock manifold and is one of the main reasons for ITB

Oakey's 2.7L is one that comes to mind on the Evolve dyno quite a while back, IIRC a stock cam and manifold and it made 225lbft and 205hp, it died in the ass at 5200rpm but all it need was a nice cam and exhaust