8000 rpm/300 bhp 3.2 rebuild

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Nine One One
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Re: 8000 rpm/300 bhp 3.2 rebuild

Post by Nine One One »

I thought PMO used Weber venturi’s?

Amallagh on here used to list some, whether he still has a supply/stash in his hoard?

Good thread here may be of interest re throttle body and venturi sizes.


http://forums.pelicanparts.com/porsche- ... 2-8-a.html
Last edited by Nine One One on Fri Apr 22, 2022 10:32 am, edited 1 time in total.
911hillclimber
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Re: 8000 rpm/300 bhp 3.2 rebuild

Post by 911hillclimber »

Thank you both.
Will follow them up.

design911 don't list them anymore.
Last edited by 911hillclimber on Fri Apr 22, 2022 10:32 am, edited 1 time in total.
73T 911 Coupe, road/hillclimber 3.2L
Lola t 492 / 3.2 hillclimb racer
Boxster 987 Gen II 2.9
neilbardsley
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Re: 8000 rpm/300 bhp 3.2 rebuild

Post by neilbardsley »

Sry another stupid comment but unfortunately you will only know what is best for your engine and rpm range by trying different sizes? To draw your own graph?

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Nine One One
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Re: 8000 rpm/300 bhp 3.2 rebuild

Post by Nine One One »

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MikeB
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Re: 8000 rpm/300 bhp 3.2 rebuild

Post by MikeB »

+1 for Larry, great guy ;)
Cheers

Mike

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911hillclimber
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Re: 8000 rpm/300 bhp 3.2 rebuild

Post by 911hillclimber »

Sent emails. Just bought a 500mm length of 50.8 x 4.8mm wall alum tube for £16.

With a light machine on my little lathe that's 50 od and 41.2 ID, so 50/41.2 chokes. A day machining them and job done and cheaply, set of chokes for about £20. :)
I'll strip one choke out of the current carbs to see the internal form, hopefully simple!!
73T 911 Coupe, road/hillclimber 3.2L
Lola t 492 / 3.2 hillclimb racer
Boxster 987 Gen II 2.9
RobFrost
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Re: 8000 rpm/300 bhp 3.2 rebuild

Post by RobFrost »

"46mm carbs for 3.2 litres" is based upon a certain power output. Your higher revving engine with more fuel consumption and power output will be better off with the 50mm. I think the bigger venturis will benefit you, probably take it over 300hp. A flat spot at 3,000 you won't notice. Assuming you start in first gear, you'll be starting at over 3,000 revs and struggling to transfer all your power into the tarmac in first gear anyway. After that, you'll have 3,500 to 7,000 to work with in every gear and still plenty of overlap between gears since your ratios will be nowhere near 2:1 to each other.

I think you're going to be surprised how great it feels to drive. The standard 3.2 falls off fairly sharply above 6,000 revs and by the looks of that power band yours is going to surge ahead instead.
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911hillclimber
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Re: 8000 rpm/300 bhp 3.2 rebuild

Post by 911hillclimber »

Exactly my thinking Rob! :)
73T 911 Coupe, road/hillclimber 3.2L
Lola t 492 / 3.2 hillclimb racer
Boxster 987 Gen II 2.9
Nine One One
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Re: 8000 rpm/300 bhp 3.2 rebuild

Post by Nine One One »

911hillclimber wrote:Sent emails. Just bought a 500mm length of 50.8 x 4.8mm wall alum tube for £16.

With a light machine on my little lathe that's 50 od and 41.2 ID, so 50/41.2 chokes. A day machining them and job done and cheaply, set of chokes for about £20. :)
I'll strip one choke out of the current carbs to see the internal form, hopefully simple!!

Personally I would do two sets one of 40mm and the other 42mm. Yes it may be an extra hour on the RR but at least you will know one way or the other what is producing what, and when?
911hillclimber
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Re: 8000 rpm/300 bhp 3.2 rebuild

Post by 911hillclimber »

Stuck with available tube sizes or I will have a lot of machining to do.
Now have a drawing of the cross section of a weber choke so can scale it up to suit.

This will be a crude experiment and can be tried when the Rollers are 'free-er' in the early summer.
73T 911 Coupe, road/hillclimber 3.2L
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Boxster 987 Gen II 2.9
Gary71
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Re: 8000 rpm/300 bhp 3.2 rebuild

Post by Gary71 »

Also try just taking the filters off, I doubt they are holding it back, but it would answer the question!
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Re: 8000 rpm/300 bhp 3.2 rebuild

Post by wadsworthi »

I think the Venturi are PMO design not Weber. The jets are mainly the same as Weber and easily obtained. I bought a set of Venturi from Tuthills a few years ago and they did have spares in stock at the time, they should know if PMO are still in business.
911hillclimber
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Re: 8000 rpm/300 bhp 3.2 rebuild

Post by 911hillclimber »

More info and details tomorrow evening after race day at Prescott, but have to honestly say what an utterly fabulous engine I now have in the Lola.

What a different engine, and the soundtrack when in the car is way beyond my expectations.

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73T 911 Coupe, road/hillclimber 3.2L
Lola t 492 / 3.2 hillclimb racer
Boxster 987 Gen II 2.9
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MikeB
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Re: 8000 rpm/300 bhp 3.2 rebuild

Post by MikeB »

Result ;)
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Re: 8000 rpm/300 bhp 3.2 rebuild

Post by jwhillracer »

I’ll vouch for that too. The Lola sounded fabulous! :-)

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