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JK 24v 3liter ..at last!

Posted: Sat Feb 05, 2011 5:57 am
by Jim K
Well, it came alive two days ago and it drove a couple of miles to the exhaust shop on headers alone...noisy trip! Here it is, coming out of the shop:
http://www.youtube.com/watch?v=JwFK8lncd8o
Will pick it up on Monday. its running the std 164Q4 management and it'll stay that way with just mapping on the dyno after the first ~2000km. A new wiring harness will be tailor-made for this installation, as I want everything to look oem. Lets see how much power this thing will show!
Jim K.

Re: JK 24v 3liter ..at last!

Posted: Sat Feb 05, 2011 11:11 am
by Michael
Nice! Does the plenum restrict power when installed on a 24v?
Also, are those standard Alfa 164LS coil plugs?
Really clean installation :)

Re: JK 24v 3liter ..at last!

Posted: Sat Feb 05, 2011 12:18 pm
by Jim K
The coils are std alfa 164Q4 items, which I assume are common among all Alfa 24v engines. We'll know about power come dyno time. I may just stick a vacuum gauge and monitor plenum pressure! Will that solve any mysteries? :?:
Jim K.

Re: JK 24v 3liter ..at last!

Posted: Sat Feb 05, 2011 5:08 pm
by la_strega_nera
Will be interested to hear what it's like to drive compared to the 1.8Ts...
Looking at picking up a 75 Twinny to either build a turbo motor for, or put the 24valver I've got into...

Re: JK 24v 3liter ..at last!

Posted: Sat Feb 05, 2011 11:05 pm
by Jim K
Ben, at least for the 1.8T: even before we get the 24v car back, there's no comparison at all between any 3liter and a factory 1.8T up to ~3500rpm. The T is dead up to that point. Now, if you really play with it management-wise, bump CR up a bit and use a different snail, you can improve things a lot and boost from ~2500, but below that...3liters rule. If you accept this, fine. The TS should be much better than the 1.8T in this respect but still, lower down don't expect any meaningful comparison! I say this as I'm always considering daily city driving. But then again, in a congested environment you never get the chance to move fast enough to appreciate anything! :)
Jim K.

Re: JK 24v 3liter ..at last!

Posted: Sun Feb 06, 2011 1:24 am
by Mats
Except the ladies of course... 8)

Re: JK 24v 3liter ..at last!

Posted: Sun Feb 06, 2011 4:33 am
by fedezyl
Lovely indeed, makes me want to put my 24v in the Giulie!
:D

Re: JK 24v 3liter ..at last!

Posted: Sun Feb 06, 2011 6:15 am
by Greg Gordon
It starts nicely and sounds great. All that black makes it look sinister. Nice job making the headers, they look good, and I know that was a lot of work.

I doubt the plenum itself would be restrictive, the runners plenum's outlets, and the runners might be, but the shape and volume of the plenum should be fine.

Greg

Re: JK 24v 3liter ..at last!

Posted: Sun Feb 06, 2011 6:24 am
by Giuliettaevo2
The plenum is too small for a NA 3.0 engine... The 3.0 plenum used on the 164 and other fwd models has a larger capacity. :wink:

I think Kevin tested with a enlarged plenuw once...

Re: JK 24v 3liter ..at last!

Posted: Sun Feb 06, 2011 7:30 am
by Jim K
What you don't see is the underside of the plenum. I grafted the Q4 plenum outlets to the rwd plenum underside and them 6 holes are very well radiused and 47mm ID. The Samco reducers connect these to the sawed-off large chrome runners. If at any time it is determined the plenum is too small (currently 2.2lt volume) there is always room to enlarge it by welding another plenum half towards the driver side.
Jim K.

Re: JK 24v 3liter ..at last!

Posted: Sun Feb 06, 2011 9:38 am
by JohnGTA
Very nice 8)

Re: JK 24v 3liter ..at last!

Posted: Sun Feb 06, 2011 12:03 pm
by Greg Gordon
Very cool work on the plenum. I never thought of that, grafting in the whole Q4 plenum bottom and cutting Q4 runners, clever.

Greg

Re: JK 24v 3liter ..at last!

Posted: Sun Feb 06, 2011 12:11 pm
by Zamani
That plenum was enough for Beninca's 278 whp GTV6, I doub't it's really too small for ~ 300 bhp applications.

Re: JK 24v 3liter ..at last!

Posted: Sun Feb 06, 2011 12:36 pm
by Jim K
I confess I prefer the rwd symmetric look plenum over the one-sided chrome pipe and plenum affair. The length (valve to plenum) is ~29cm in the rwd setup and ~32cm for the chromes, so what the hell, I'll take whats coming!
As a matter of fact, the Performance Trends engine simulator shows a clear advantage of the rwd arrangement -see attached graph! The only difference in data input is 290mm length in one case and 320mm in the other, everything else being the same. The red line is 290mm from valve to plenum.
Jim K.

Re: JK 24v 3liter ..at last!

Posted: Sun Feb 06, 2011 7:05 pm
by la_strega_nera
Lovely.
Under 3500rpm doesn't bother me the slightest :P
Logic says put cams into 3l and run it with a squadra chip as opposed to building up the 1.8 alfetta parts motor for boost and going aftermarket management... all fantasy land at the moment though - need to get rid of the 164 and the mustang.