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knight · Guest

is the SPRINT 1.7 8V engine fitted with 36mm or 40mm carbs?.....

paulhide · Posted: Thu Mar 16, 2006 3:14 pm Post subject:

Well on the 33 the 1.5 took 36 mm carbs and the 1.7 took 40 mm. Can't see why the sprint should be any different.
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http://www.alfa-pages.co.uk/viewtopic.php?t=5188

Bellamachinna · Posted: Thu Mar 16, 2006 4:26 pm Post subject:

The Sprint 1.7 uses the same carbs, used by the 33 1.7 QV.

So 40mm´s...
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Guest · Posted: Fri Mar 17, 2006 4:31 am Post subject:

my 1.7 sprint had webber 40,s on it so they should be the same

tinworm · Posted: Fri Mar 17, 2006 11:18 am Post subject:

Just out of interest, what would a 1.7ie motor perform like with 36's instead of the standard 40's? Obviously it would run out of puff at higher rev's but low down it would perform as well or probably even better than the 40's, no?
They are only 200cc's between the 1.5 and 1.7 and I have two sets of carbs for a 1.5 and no forties for my spare 1.7ie. The last set of 40's on eBay went for silly money, or more than I was willing to pay anyway.
Might be a way of testing my spare motor out anyway.
Anyone done this and can tell me please?

Cheers,.... Col.
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1977 Alfasud ti 1.7
1985 Alfa 33 4x4 1.7
1968 1750 GTV
1986 Alfa Sprint 1.5 QV

knight · Guest

to my knowledge both the 36mm and 40mm carbs are both fitted with 32mm chokes, weather on a 1.5 or 1.7...... the choke is the main part that will restrict the incoming air throught the carbs.......I have a 1.5 sud motor in my kit car on dual 36mm webber carbs, and personally I think 40mm carbs would be too big, the motor would be gut less at low rpm.......I have just bought a 1.7 8v sprint motor on 40mm Dellortos, again fitted with 32 mm chokes, I have read elsewhere on this forum that by fitting the 16v pistons in order to increase the compression ratio to 10.8:1 and fitting bigger 34mm chokes to the carbs will result in a power increase of around 20bhp......standard is 115Bhp......so I'm hoping for abot 135Bhp......possibly a bit more as I might have the heads ported, and fitted with bigger valves.......hope that helps Wink

tinworm · Posted: Sat Mar 18, 2006 11:58 pm Post subject:

Hey, that motor sounds like a good deal. It's certainly one way of waking up the 'neglected' 8v engine to similar performance as the 16v job, semi plentiful as well unlike the later big lump. Well, don't know about elsewhere but in Australia anyway Razz

The carb. spec's will give me something handy to think about as well. Thanks.

Cheers,... Col.
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1977 Alfasud ti 1.7
1985 Alfa 33 4x4 1.7
1968 1750 GTV
1986 Alfa Sprint 1.5 QV

knight · Guest

yes the 8v engines aint that bad!.....I recently found that the 16v engine weighs 128Kg, and the 8v engine weighs 104Kg.......thats 24Kg extra for the 16v........as my engine is mounted on a beetle gearbox hanging out the rear of my sand rail / dune buggy, that is really something I needed to consider.....especially when the vw aircooled motor only weighs 86Kg!!!!.......I have since been told the 36mm carbs on the 1.5 motors are fitted with 30mm chokes - not 32mm, I will check my service manual for sure.......

Rees Cees · Posted: Mon Mar 20, 2006 5:50 pm Post subject:

the 1.3S (last type) has also 40mm Dell Orto´s!

The greatest problem on all the carb engines is the airintake, fuel is no problem.

I race with 40 mm dell orto´s (32mm venturies) on a fully flowed 1600 cc boxer, it gives about 190 HBP.

If you mount 40mm on a 1300, 1500, 1700 or 1700 16v (or anny other changes) you have to go to the Dyno for all the settings. If it runs to poor you lose the engine!

hugh jinjin · Alfasud Joined: 04 Sep 2004 Posts: 68 Location: Glasgow

knight, remember all that extra weight isn't all due to the heads. I have just weighed a complete 16v head with all valve gear and sprockets etc and it weight about 13kg. A lot of the extra weight on the engine comes from bits that you wouldn't be using anyway ie.
plemun chamber and airflow meter assy,
power steering pump and big front pulley,
heavier flywheel and bigger clutch which a lightweight car wouldn't need.
I would estimate that the 16v engine on carbs as you would use it would only weigh about 12-13kg more than an 8v.

Rees Cees · Posted: Tue Mar 21, 2006 5:23 pm Post subject:

knight · Guest

its too late to try and convince me about the 16v.....its a good engine, but I already have a 1.5 sud motor fitted to my beach buggy, and the 1.7 8v on 40mm carbs offers me the easiest upgrade option.......If I were to run a 16v it would be using the standard plenum etc, so it would still be heavy, I dont want to get involved with converting to carbs or throttle bodies. an 8v with about 140bhp will be just what I'm looking for.......I have lots of wanted ads out on the web at the moment, so am hoping to pick-up some tuning parts for sensible prices

Serpent33 · Posted: Wed Mar 22, 2006 5:31 pm Post subject:

I last weighed, it's about 12-13 too. I'm damn happy with the 8 valve engine. Will be putting in the carbed 16v soon. Need to really try before concluding is the extra weight worth it.
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Each time I speed I say, "Dear lord, make me fast and accurate..."