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MarkJ

MJ's 3.2 Engine Build

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I see FVD do a modified throttle body for a 964  too , wish I hadnt seen that ! Got me thinking perhaps I should bore mine out too  Little info though as whats been done,    .

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2 hours ago, Chris T said:

Shrish, I have after your previous recommendation, tried to find the chap to whom you refer and I failed. I've looked at others BMW forums, again no joy.

I intend to do the job this winter, so I should start looking again!

Chris.

His username on various forums was/is 'alpina527' (Ian)

Google that and e36/M50/BBTB (Big Bore Throttle Body) returns a few pointers, although admittedly not much in the last 12 months.

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a couple of you have mentioned ITB's as an upgrade, whats involved cost and process wise in getting these? Is there somewhere I can read up about them?  Already spent too much money this year, but could be my next step in the new year. :-)

I had assumed my next logical upgrade would be 3.4/3.5 capacity increase with lairier cams or slap a 3.6 in it !

Edited by MarkJ

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Can you clarify how your motec is working?  Is it alpha-n and throttle position?  Or is there still some kind of air flow meter (original or Bosch/993 type MAF)?

IMHO, once you are on motec and ditch AFM, the marginal gains on ITBs are small and if you ditch the common plenum intake, you might go backwards in terms of area under the curve.  A GT3, Singer etc uses ITBs under a plenum because the plenum is important for inlet length tuning and real world drivability.  Your main restrictions are now what cams you can run (valve clearance) and how many revs (what have you done to build to a higher rev limit?).  If you can safely run 7500rpm and have a cam that makes power/tq over 6000rpm (ie., not a 20/21 which seems to die on your dyno graphs more quickly than my old Supercups did), you will make lots more hp simply by the maths of turning more revs.  Motec lets you do all that, where the combo of std pistons, ECU and AFM severely restrict you.  ITBs - look at the Jenvey website for an idea on price, though there are other alternatives - are not a necessary ingredient to further development.

You may have a tiny hint of disappointment that you have a headline 260hp number rather than a 270 or 280, but it sounds like you have an engine that is in every respect near identical to my old one in terms of driving, perhaps better.  And that was a peach once you were really on it.  Not the effortless 3.6/3.8 grunt, but when wound up it did the business.  I would keep my chequebook in my pocket for a bit and see how it drives.  Spend the cash on Pyrenees trips :) 

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33 minutes ago, Richard Bernau said:

  Spend the cash on Pyrenees trips :) 

+1 - despite having done a 5000mile round Europe trip on the engine,  I swear mine loosened up after the last Pyrenees trip. Redlining it in 2nd gear is the best type of Italian tuning possible IMO...:001-17-revto9k:

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Sage advice,  :ani_clapping:  problem Is I probably will not ever be truly happy until I have RS/RSR type performance under my right foot :D  but I'll probably be old and retired before I can afford it :blush:

Re Motec, I think its alpha/throttle, no MAF.

Your probably right about the 3.2, it feels very strong and revs to 7k no problem. Watching it compared to Longers 3.4 <_< at Goodwood, it seemed to hit the same speed/revs in 4th on the Levant straight (until I started upshifting to 5th) and despite some mapping issues I was (for once!) 'almost' keeping with him at Oulton this year.

I'm not in any rush to tear it apart and spend yet more k on it and i've only done Oulton and Goodwood this year since the rebuild so plenty of smiles per miles to be had as it is. Just nice to hear what options I have got when it does come to thinking of stepping it up.

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32 minutes ago, MarkJ said:

...I was (for once!) 'almost' keeping with him at Oulton this year.

Its his big clown feet - pushes down harder on the throttle :whistling:

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9 minutes ago, Lesworth said:

Its his big clown feet - pushes down harder on the throttle :whistling:

More leverage...

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5 hours ago, Lesworth said:

Its his big clown feet - pushes down harder on the throttle :whistling:

Or maybe hot air intake plumbed into the drivers seat? ?

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FWIW, Neil has just built a 3.4 engine on Motec hitting 296bhp/250 torque - no carbs or ITBs, just alpha-N and MAP/TPS (TBC); hopin to get full specs if i see him this weekend

If you're looking at 3.6, this is the Rothsport kit he's recently fitted to a customer's car recently - no idea on internals or dyno figures, but uses a common plenum over ITBs.  I think circa 15-18k USD for the bolt on kit, with estimates of 100bhp/litre on a 3.6 with correct cams when i was in discussion with super helpful William Knight of Knight Racing in Trumpland

 

 

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Mark - you already have RS/RSR performance.  I spent a week following Leonards "Hulk" (300+hp RSR race car) and Gert's white RSR (280+hp RSR race car) and there was nothing in it on the road when overtaking, out of hairpins etc.  You LW and hp/tq of a 3.0RS.  The only things you don't have are the front end turn in (hard to get in narrow body) and traction (impossible without a good diff).

You don't need £20k of Rothsport/GT3/ITB goodness to get 90hp/litre.  My build was over 88hp/litre and I know of real 3.6 engines on Motec and Supercup cams making just over 90hp/litre.  Sure, if you really need 100hp/litre then spend the £££.

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On 10/19/2017 at 9:52 PM, SP72 said:

no carbs or ITBs, just alpha-N and MAP/TPS (TBC)

So does it use alpha-n most of the time and the MAP sensor at small throttle openings?

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