If you put larger throttle bodies on then you MUST match the intake ports! Otherwise the air fuel mixture will stall when you run the engine .... which will cause all sorts of power fuel/mix problems.
No idea if it's worth it on these cars - I'd say best thing to do is get your 3.6 running as BMW intended rather than trying to change it .... it will be far, far cheaper!
Plus, how would you intend to fuel your new hybrid 3.6/3.8 engine? You'll have to budget $2000 for ECU and mapping as well.
If you put larger throttle bodies on then you MUST match the intake ports! Otherwise the air fuel mixture will stall when you run the engine .... which will cause all sorts of power fuel/mix problems.
No idea if it's worth it on these cars - I'd say best thing to do is get your 3.6 running as BMW intended rather than trying to change it .... it will be far, far cheaper!
Plus, how would you intend to fuel your new hybrid 3.6/3.8 engine? You'll have to budget $2000 for ECU and mapping as well.
Stick with stock and enjoy it
What?
Your best bet to understand the true tuning potential of these engines is to invest time trawling www.s14.net and www.s14power.com
If a 2.5 l s14 can get 300hp, then a 3.6l s38 b36 has a lot left to give.
Adding larger TB's will not net any gains without porting the head. However, 50mm TB's, ported head, 280+++ cams, CF airbox will add signifcantly.... (then you will need 3.8 or M6 exhaust extractors..) A stock 3.6 doesnt breath very well above 6500 rpm. I guess you're looking at 5k for all that, but I don't see why you couldn't get another 60hp+ at the top end without any loss in torque.
Do you have a lightweight flywheel?
I must say I am surprised by the lack of proper tuning on this forum. I guess the M5 is more of a GT than a track rat though : )
Ash
Last edited by AshNZ; 24th June 2008 at 11:49.
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What bit do you not agree with? You've just agreed with me that if you put on larger throttle bodies you need to port the head!
Quote:
I must say I am surprised by the lack of proper tuning on this forum. I guess the M5 is more of a GT than a track rat though : )
Ash
Probably because it's so expensive and replacement engines are hard to come by if you get it wrong! Far easier to tune a 2.5 as you can pick up a new one for peanuts
I notice you don't mention engine management - what are you using??
Sorry, I should have been more specific with my quotes
I don't agree that the car will stall if put 50mm TB's on and dont port the head. The air vortices will certainly be messed up, but the car will run.
The fueling is on the chip, so you could get a chipped mapped, as opposed to a Full ECU replacement. Although if you had a CF airbox and no MAF you will need a piggyback Alpha-N or stand a lone sytsem (motec etc).
A proper 300hp s14 is 25k for the motor. Hardly cheap, but getting quite common. s14 guys use much much more high end stuff than M5 guys.
I haven't seen flow bench testing for the 50mm vs 46mm throttle bodies (only 46mm vs 48mm from the s14) so I can't say what sort of gains to expect except that they will probably be in the 5k- 8k rpm range.
Sorry, I should have been more specific with my quotes
I don't agree that the car will stall if put 50mm TB's on and dont port the head. The air vortices will certainly be messed up, but the car will run.
Ah sorry, I used the wrong term! I meant "stall" in terms of the flow of air will be messed up, rather than the engine will stall .... so we're in agreement
Quote:
The fueling is on the chip, so you could get a chipped mapped, as opposed to a Full ECU replacement. Although if you had a CF airbox and no MAF you will need a piggyback Alpha-N or stand a lone sytsem (motec etc).
Indeed - I'd prefer a proper standalone than a Unichip, but for such a relatively uncomplicated engine maybe a Unichip is good enough ... certainly modern engines with their arrays of sensors need Motec or similar!
Quote:
I haven't seen flow bench testing for the 50mm vs 46mm throttle bodies (only 46mm vs 48mm from the s14) so I can't say what sort of gains to expect except that they will probably be in the 5k- 8k rpm range.
Good stuff - which means in the "real world" they won't do much on their own .... for a track car that would be excellent though.
I got a 2 lap ((one full-lap )) on the Nürburgring Nordscleife
in a 1983 635 csi RENNWAGEN nr. 031 @ 151 built by BMW motorsport
((it was a 1984 champion car )),,
that car had a S36B36 engine with B38 throttlebodies ..
the owner Walter Löffler told that the oem M30B35 race-engines was so expensive to build,, that he bought this engine and had the 3.8 throttlebodies on + some mods,, ((custom airbox and blabla,, the engine output is 352 bhp.... he also use the 3.8 exhaust manifold ((the M88 has best headers but ...€€€€€€€€€€€)))
he also told me that the 3.8 engine is NOT good for racing.. and there is a minor work on the intake side to let the 50 mm ITB fit on ..
But remind ,,his task was a solution ,,to use for a RACE engine
I think Nepbor is quite correct in stating that the best 'tuning' is trying to get the 315hp BMW initially put in.
As to lack of tuning on S38's, lets just say that E30 M3 owners and E34 M5 owners are a different breed, although some of us have E30 M3's aswell. The E30 M3, a great car as it is, simply lacks power to take on a 325i these days. The chassis is still sublime, but the outcry for more power ( which is ridiculous IMO since the car is a classic, you wouldn't go putting bigger carbs on your Silver Ghost now, would you? ) is much more appropriate there than for the E34 which is a fast car even considered by normal stds ( 996 won't take a 3.6 in gears 3-4-5)
Although similar in concept, the S38 and S14 are definately not comparable when it comes to tuning.
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