Lightweight flywheels and Dbilas throttles?

[Mikey_Boy]

Hi Everyone,

Ok - without opening a can of worms here - I am debating either to install an M52 or tune a spare M20 that I have for my 325..

So - focus here is clearly the M20 route. Let's also ignore the relative costs! It's going to be a stroker, 2.8, 885 head, 288 cam, BTB exhaust, MAF conversion etc. Its for a road legal trackday car so plenty of poke at the top end is key as well as a responsive lump with good throttle response.. Any views on flywheels?? Standard or lighten best with big cams?

Also - heard that Dbilas throttles give more mid range torque, what about power gains? Anyone have any experiences to share??

Many thanks!
Mikey_Boy

[e30topless]

I almost did the Dbilas thing, they aren't cheap and anyone that has done this has never got any gains ?

looks awesome in the bay !



the cheaper and better option would be the M52

[reggid]

lightened flywheel is a good mod will pull better in the lower gears with this mod. Steer clear of the dbilas ITB setup IMO mod they tend to flatten out the midrange from what before and after i have seen.

[Mikey_Boy]

Thanks Guys - very helpful! Anyone else got any experience of DBilas throttles...? Surely someone on here has tried them??

Reggid - You have got some awesome power out of your M20 - I read your other thread - really excellent job!

I already have the BTB exhaust (I am a sucker for nicely welded manifolds - I know it's sad!), a 288 cam ready to install, 2.8 M52 crank and spacer ready to go, MAF conversion installed. The exhaust and MAF have made a big difference already, but very keen to make that next step with a fresh block, decent pistons and rods etc etc

M52 looks like easy power if a pain to install, M20 is a lovely engine that begs to be tweeked!

Any other experiences or top tips are most welcome!

Cheers,
Mike

[Simon13]

lighter fly is a 100% must, even wakes up a stock 2.5

[e21Jason]

One of the guys with a 2.5 conversion in an e21 has the diblass set, emerald ecu and modified cam and see juat about 200hp

The thing about the m20 is that all the components seem balanced with out a single item giving a big gain. So you have to go the whole hog to get decent power, ie six branch, throttle bodies, higher comp, better flow, bigger cam.

[Mikey_Boy]

Thanks guys - again, most helpful! I am coming to the same conclusion as e21Jason... In other words it's proper old school tuning!

A final spec is starting to come together in my mind now - it ain't gonna be cheap but it should be fun to see what can be squeezed out of the old girl on 12 valves:

2.8 M52 crank, custom pistons and rods.
11 or 12:1 compression
288 cam
Uprated injectors
Heavy duty rockers
Light weight flywheel
324d oil pump
Baffled sump
Windage Tray
Dbilas throttle bodies
MAF conversion
BTB manifold and exhaust
Cold inlet to throttle bodies.

Have I forgotten anything??

Time to get saving! Coupled to my 262 G/Box and 3.64 diff that should hopefully be quite a weapon on track...!

Cheers,
Mike

[Mikey_Boy]

I did forget to mention ARP fixtures and a decent headgasket as well...

Cheers,
Mike

[GeoffBob]

Sounds like a real monster Mike.

Personal preference, but when it comes to throttle bodies I'd lose the MAF and tune her Alpha-N. Six ITB's with six trumpets and a nice big filter with a supply of cold air to the filter would about do it for me. But that's just my preference, not intended to influence yours.

BTW, I know its not what you are planning, but have you seen what Tim Haynes did with his M20B25 here

[AlpineAde]

Mike, if you are still really keen on going the ITB route perhaps have a look here:

http://www.extrudabody.biz/servlet/the- ... ITB/Detail

I know nothing about them, unfortunately. I came across them on another forum ~ a lot cheaper than the Dbilas.

[Mikey_Boy]

Oh my - that is interesting!

Decisions decisions...!

[reggid]

One of the guys with a 2.5 conversion in an e21 has the diblass set, emerald ecu and modified cam and see juat about 200hp

The thing about the m20 is that all the components seem balanced with out a single item giving a big gain. So you have to go the whole hog to get decent power, ie six branch, throttle bodies, higher comp, better flow, bigger cam.

I have seen a before and after of a dbilas ITB kit and the results were poor. All the midrange that the stock manifold produced was lost and peak power hardly changed. The kit so far seems to be for show only. Bore is too big and runners seem too short.

[reggid]

Mike, if you are still really keen on going the ITB route perhaps have a look here:

http://www.extrudabody.biz/servlet/the- ... ITB/Detail

I know nothing about them, unfortunately. I came across them on another forum ~ a lot cheaper than the Dbilas.

they sell with a 45 or 48mm kit

but this suggest 40mm is better suited

http://extrudabody.com/TechInfo/Sizing.html

Thats what i would be looking at if i was going to do an ITB setup. Also saw some where they have adjustability in length so you tune the length what what the engine actually wants.

Also get to make your own plenum (shows how on the website)

[Mikey_Boy]

Thanks guys for the input... Looking again at the modular kit above in a little more detail, I think the injector is placed a bit too far away from the intake valve - potential for lots of wall wetting and all the nasties that come with that...

Clearly the standard intake manifold is tuned for bundles of mid range and a compromised top end - I was rather hoping the DBilas might address that a bit - the short runners (without knowing the dimensions to do some sums) should help the top end a little ifyou are reving it hard enough with a big enough cam, with the plenum helping to drag up the mid range...

Primary reason for looking at the ITB's was to aid throttle response (I do have a MAF already - that has helped quite a bit compared to the AFM!) and mask some of the overlap effects of the cam I have planned...

Thanks Reggid for the info - do you have any more info to share on the before and after work please, such as the spec of the engine the kit was tested on? I can understand why folks are reluctant to invest that amount of cash if the results ain't that good!!

Cheers,
Mike

[reggid]

Thanks guys for the input... Looking again at the modular kit above in a little more detail, I think the injector is placed a bit too far away from the intake valve - potential for lots of wall wetting and all the nasties that come with that...

Clearly the standard intake manifold is tuned for bundles of mid range and a compromised top end - I was rather hoping the DBilas might address that a bit - the short runners (without knowing the dimensions to do some sums) should help the top end a little ifyou are reving it hard enough with a big enough cam, with the plenum helping to drag up the mid range...

Primary reason for looking at the ITB's was to aid throttle response (I do have a MAF already - that has helped quite a bit compared to the AFM!) and mask some of the overlap effects of the cam I have planned...

Thanks Reggid for the info - do you have any more info to share on the before and after work please, such as the spec of the engine the kit was tested on? I can understand why folks are reluctant to invest that amount of cash if the results ain't that good!!

Cheers,
Mike

Injector placed further away is there to give more topend power

Here is the build thread, I can’t remember if you need to register.

http://www.e30clubsa.co.za/forum/index. ... -m20-325i/

the guy who installed them thought they were too big, too short and plenum very restrictive.

There is nothing wrong with an ITB system but it has to be sized and designed for your application.

The thing I have learnt is that relying on things like in theory the shorter bigger bore runners should help topend with a suitable cam are not enough it is far too complicated. I have seen numerous results with cylinder head port size that are too big such that when they are filled in/reduced the power went up everywhere. What is to say the runners on the dbilas aren’t too short? What is to say that your engine wants bigger bore runners? Maybe all it wants the same bore as stock but a couple of inches shorter
If you want an ITB system you want adjustability so that you can tune it to get the best from your engine.

I would build the engine with a stock manifold and see how you like it then look at other alternatives once you have established that you need it.

[Mikey_Boy]

Thanks Reggid - all good points - hopefully my background will help me to make the right decisions...! More digging required certainly to understand more fully Be careful about injector positioning though - like the other things you mention above - it isn't that simple!

I have been advised elsewhere that ITB's are something to 'grow into' with an M20 so I think I shall have a look at what can be done with the standard intake first before committing...

Naturally I shall put a build thread on here once my money tree doesn't look quite so wintry and bare!

Thanks all...!
Mike

[AlpineAde]

Mike, if you are still really keen on going the ITB route perhaps have a look here:

http://www.extrudabody.biz/servlet/the- ... ITB/Detail

I know nothing about them, unfortunately. I came across them on another forum ~ a lot cheaper than the Dbilas.

they sell with a 45 or 48mm kit

but this suggest 40mm is better suited

http://extrudabody.com/TechInfo/Sizing.html

Thats what i would be looking at if i was going to do an ITB setup. Also saw some where they have adjustability in length so you tune the length what what the engine actually wants.

Also get to make your own plenum (shows how on the website)

Yeah, I know matey. 45mm and larger is too much but I thought that ~ given Mike seems really keen ~ why not have give him a chance to have a look at a cheaper alternative to the Dbilas.

[HairyScreech]

i looked into this briefly before (and will do much more indepth when i get some damn free time.) but i came to the conclusion that something around 38mm was correct.

although we have a 2.5-2.8l engine its split over 6 cylinders so really we are only looking at 416cc-466cc per cylinder which is equivalent to a 1.66L-1.86L 4 pot. a 45mm throttle per cylinder is too much on a 2l 4 pot let alone a 1.6 or 1.8.

i would also say the runners on both sets of throttles in this thread so far are too short, the port in the head of the m20 is short, so coupled with a short runner your looking at far too little inlet runner length.
i havent got a figure for correct length but id estimate it at twice what the runners on those throttles are.

[AlpineAde]

i came to the conclusion that something around 38mm was correct.

That is much nearer the mark, I reckon.

[Mikey_Boy]

Yes - I did some (basic) sums and also came to a figure somewhere south of 40mm... No wonder the DBilas are rubbish in traffic - FAR too much throttle area for part load transients! It also looks pretty naff for AFR distribution as well across the plenum. I imagine it works a touch better with the extreme strokers...

From the 6 cylinders I have developed in my dim and distant past (mainly Vee's admittedly, but some revving to 14k - DTM old school...!), the ideal intake set up is something variable - so whatever is bolted on that's fixed is always going to be a compromise. From memory (it was a while ago and a road engine that never made it to production) a 6 responses well to short runners to about 2100, looooooooong up to around 5200, then short again up to 7k.

So, with that in mind, it looks the BMW guys did a pretty good job on the M20 intake back in the day... So looks like I will spend some cash on a standalone ECU and BBTB instead.

As another thought - anyone looked at extrude honing on a standard intake manifold??

Cheers,
Mike

[e301988325i]

A final spec is starting to come together in my mind now - it ain't gonna be cheap but it should be fun to see what can be squeezed out of the old girl on 12 valves:

2.8 M52 crank, custom pistons and rods. - £2-3k new engine parts
11 or 12:1 compression
288 cam £400
Uprated injectors
Heavy duty rockers - £500
Light weight flywheel
324d oil pump - £200
Baffled sump
Windage Tray
Dbilas throttle bodies - £2K
MAF conversion - what, with throttle bodies?
BTB manifold and exhaust - £3K
Cold inlet to throttle bodies.
Mega Squirt or similar - £1k inc mapping

fitting building of the above

Have I forgotten anything??

Time to get saving! Coupled to my 262 G/Box and 3.64 diff that should hopefully be quite a weapon on track...!

Cheers,
Mike

I've put some purchase figures to your list above, I reckon you've got £10k plus there, and an awesome M20.

You are not comparing M20 with M52 ina ny way shape or form,

With your budget then you could drop in aluminium blocked E46 M3 S54 b32 with 340bhp, which would be a lighter engine that comes with a six speed box.

[AlpineAde]

As another thought - anyone looked at extrude honing on a standard intake manifold??

I tend to agree on the BMW design. For what it is it isn't bad.

I did look into extrude honing but the sheer cost of it put me off. There is a company in America that offers an exchange service for it but, by God, you'll stagger a little under the price.

[Mikey_Boy]

I was afraid that the extrude honing might cost a bit - I am UK based so a few companies that service the motorsport industry in Northants that may be able to help - watch this space if I find anywhere as there may be a group buy in there...??

Thanks e301988325i - I appreciate the help! Understand it isn't going to be cheap - just to put you in the picture, I have the BTB exhaust already (bought pre price hike!), 288 cam I have as well, MAF conversion and cold air feed already installed (BMC carbon airbox). I have the 2.8 crank and a spare M20 engine in bits with a block ready to machine etc etc. I will however, be in touch with you about a BBTB!!

I reckon the rest of the physical parts will cost about £3k - the engine I can build myself thankfully..

It's this that's really driven my original question - I love the sound of the BTB, and the originality of the M20 and love the idea of a monster M20 as it's in keeping with the car, but my business head knows that an M52 or S50 is potentially quite a bit cheaper!! Plus, I have spent a bit of time and effort getting the 262 gearbox installed (and it's brill!), hence the reason why I am thinking the M20 route is a better, if less logical step...

Having had all the help and advice, I am pretty sold on going the M20 route... But then I might change my mind next week, especially if I could source a pair of US spec M3 cams for an M52...



Cheers,
Mike

[e301988325i]

Monster M20 sounds good and I like the originality too.

Tell me about the 262 box?

I can't do BBTB's anymore as I've been promoted off the shop floor.

[Mikey_Boy]

Indeed! Plus, doing it from scratch also appeals... Congratulations on your promotion!

The 262 box happened after I realised that I was only using 2 or 3 gears on trackdays with the Sport gearbox on my 325i - I wanted a close ratio set up without going to the (superb and extremely well thought out) lengths that Geoffbob has on his race car, so after a bit of digging the 262 gearbox seemed to fit the bill.

So, I bought a 262 box from an M535i (same as an M3), bought a US spec 525e bellhousing, modified the propshaft to suit (M5 front end, shortened, standard centre bearing and rear end) with the 3.91 LSD. Top end is limted to about 120mph, but it gets there mighty quick! I have a 3.64 LSD waiting to go in so that when the more powerful engine goes in, the grunt will mask the slightly longer gears and should be good for about 135 flat out at 7k rpm, with excellent acceleration and a nice close gear set to keep the engine in the power band with a big cam. Gearshift was a challenge, but M535 bits with a little fabrication works a treat!

I am hoping that around 220hp and the short gears will be a lot of fun!

Cheers,
Mike

[e301988325i]

You'll do 220bhp with the bits you've already got!

sport box ratios that I upgraded to =
1st 3.35
2nd 2.03
3rd 1.36
4th 1.00
5th 0.81

what about the 262? is it dog leg?

[Mikey_Boy]

Yep - a dogleg, direct drive top - I had the same sport box that you describe above and it's a lovely unit, but given my car is used mainly on the track I wanted something a little more extreme - my original thread is here (hopefully!):

http://www.e30zone.net/modules.php?name ... atio+gears

Gear ratios for the 262 are:

1st: 3.72:1
2nd: 2.40:1
3rd: 1.77:1
4th: 1.26:1
5th: 1.00:1

I quote 220hp as a realistic figure given my inexperience with M20 engines and to save future blushes!! I wouldn't be unhappy with more though!!

Cheers,
Mike

[e301988325i]

325i sport box with 3.64 1st/5th=3.35/0.81=0.414

1st 3.35 40.5 mph
2nd 2.03 66.8 mph
3rd 1.36 99.7 mph
4th 1.00 135.6 mph
5th 0.81 167.4 mph


262 M535i with 3.15 1st/5th=3.72/1.00=0.372

1st 3.72 42.1 mph
2nd 2.4 65.3 mph
3rd 1.77 88.5 mph
4th 1.26 124.3 mph
5th 1 156.6 mph

stock 325i, with 3.64 1st/5th= 3.83/0.81=4.7

1st 3.83 35.4 mph
2nd 2.20 61.6 mph
3rd 1.40 96.8 mph
4th 1.00 135.6 mph
5th 0.81 167.4 mph

Well that makes some interesting reading, the difference between 262 and 260 is massive, needs a low diff for road use though.

[Mikey_Boy]

It's quite a difference isn't it? I reckon if I can get 7k out of my new engine I should get about 134mph flat out. With the cam I have bought it should pull well until about 6800 so hopefully that other 200rpm won't be an issue...

A bit buzzy for the road (4200rpm will be a genuine 80mph) but should be great on track...

Once I get the engine project underway, I shall get a build thread on here and hope there is some interest - I am cheating a bit in that the cage, brakes, gearbox coilovers, seats, exhaust etc have already been done, but it would be good to document it all somewhere!

Cheers,
Mike

[fporro]

Aloha,

My apoligies for resurrecting old post, but...

- has anyone purchased dbilas chips for their itb setups ?
- or, ran a dbTronic 4500 ecu unit ?

I'm yet to read an itb built that was finished with dbilas chip, maybe that's why it feels flat at certain rpm's ?

their catalouge claims 250hp's from a stage 2 m20 2.7 (stroker I assume)
compared to their 220hp's from stage 4 m20b25 set-up.

I like my engine as n/a and debating on ms3 or dbTronic's ecu for alpha tuning.

current setup ... http://www.bimmerfest.com/forums/pictur ... reid=30662

- m20b25
- Miller MAF (3 inch housing) and WAR chip
- 45mm dbilas itb's
- 5.5kg's / 11lbs flywheel
- RD headers
- Cat replaced with resonators
- Supersprint muffler

I too like the idea of adjustable lenght runners and experimented with plastic PVC piping and made a koo-koo intake, car ran fine with it, nothing fancy and just to reasure me that plenum could be built around oem brake booster setup.

- clearance video...

- system running ...

Last week modified a csl type cf airbox for it to clear brake booster and it did, now I'll install a remote reservoir (750iL) for brake fluid., need it for clearance.

cheers and stay warm.

btw, Federicco (RD) said that it will take further develoment to run his 24v on m20's.

Mahalos for your time.
Frank

[sx_turbo]

the dbilas chip wouldnt make any difference to what you have now with the war chip,

providing the war chip is well mapped that is

[player6]

Lightweight flywheels and Dbilas throttles i have both of these on my 2.8 m20 with mbe ecu

[Kedge]

btw, Federicco (RD) said that it will take further develoment to run his 24v on m20's.

So does that mean some still exist and its something he's looking at again??

[fporro]

They still exist, but, he's not looking into further develepment at the moment.

If 50 buyers were to spet up and place their $ 2,500 deposits each, then it might happen.

I've ordered 15 sets of his original headers and he produced them, unfurtuanley not many liked their $ 900+ per set price.
So, enlisted Robert Calhoun from www.e30motorkers.com in Southern California to sell them for me as I'm in the middle of nowhere on Hawaii., they are right hand compatible too, here's link and pic of my m20 with them on ...

http://e30motorwerks.com/index/products ... rd-headers

[Kedge]

Shame that, getting that many people together will never happen. Wonder how much work they need.

$900 eh, wonder what that makes my originals worth then