Single port performance

[Marshy]

After enjoying many trips (still with a few more to come) it's time to start making plans for some winter improvements, and particularly on the engine, while the bus is great fun to drive and pulls pretty well I'd like to get a few more simple horses to pull me up them hills.
Currently I have a standard single port 1500, only mod is an empi 4:1 exhaust, having read a bit, I'm proposing a 1641, with a vs exhaust and twin carbs and electronic ignition, I'm assuming this would give me s little more oomph, is it worth changing rockers? With the extra bhp do I need more cooling?
Any comments would be welcome

Cheers

 

[sparkywig]

I ran a 1600 singleport with twin 34s, VS exhaust and 123 distributor, drove so much better than stock. I never put it on a rolling road so don't know what it put out, but it certainly pulled better up hills.
Drove it all over the country, never needed any additional cooling.

 

[Marshy]

Thanks sparkywig, sounds like you ran what I'm after. Spent some time looking at your bus at skegvegas, nice! And was glad to see my bus in your photos

 

[sparkywig]

Thanks sparkywig, sounds like you ran what I'm after. Spent some time looking at your bus at skegvegas, nice! And was glad to see my bus in your photos

:?

I never went to Skeg....

 

[Marshy]

Ha ha, I'm a muppet, wrong member lol

 

[ozziedog]

I never went either :lol: I`m running 1641 twin 34s a teeny bit of cam and a VS zoorst. It`s really good and I very rarely have to change down. It`s still nothing like a modern motor or nothing like some of the big motors like Wig is running now, but it`s better than stock. The main improvement is a rebuilt or new 1641 is gonna be an improvement over a slightly smaller and possibly tired and older 1500 / 1600. I`m just saying you still don`t need to brace yourself when you plant that right foot :shock: You can just about beat off the Gs as you accelerate if you know what I mean :lol:

Ozziedog,,,,,,,,,,,,,,,, Might need a chute fitted though :lol: :lol:

 

[911gt2]

After enjoying many trips (still with a few more to come) it's time to start making plans for some winter improvements, and particularly on the engine, while the bus is great fun to drive and pulls pretty well I'd like to get a few more simple horses to pull me up them hills.
Currently I have a standard single port 1500, only mod is an empi 4:1 exhaust, having read a bit, I'm proposing a 1641, with a vs exhaust and twin carbs and electronic ignition, I'm assuming this would give me s little more oomph, is it worth changing rockers? With the extra bhp do I need more cooling?
Any comments would be welcome

Cheers

You don't need additional cooling as long as you make sure the standard one is working ok.
Dual carbs do come with extra noise. That's maybe worth to consider?

Why do you opt for 1641? Becaus it's the largest slip-in I guess right?

 

[megaaircooledvw]

Largest slipins are 1679 ,88mm thin walls.

 

[Marshy]

was gonna go 1641 as a nice easy bolt on, didn't realise there was a larger slip in, is the wall too thin?

 

[megaaircooledvw]

For a bus yes,depends on what help you give the engine.

 

[Marshy]

May avoid that one then, I'm not after high gains just something to help me along the way, if I go too big it's gonna cost a lot with brake upgrades etc

 

[sparkywig]

For a bus yes,depends on what help you give the engine.

Sorry to disagree with you, but I ran a 1679 with a Weber 32/36 and stock cooling in my '72 Devon for years back in the late 90's/early 00's.
It was a daily driver and used to run up and down the M5 fully loaded to the North Devon and Cornwall coast every weekend without fail.

 

[weeboll]

I would think its splitting hairs when it comes to the difference between 1641 and 1679..


whilst you've got the heads off, I would get them a minor porting if you can, singleport heads respond well to being opened up a bit

i'd also convert the cooler to a doghouse cooler to give some headroom. things will get hotter if your chucking more fuel in, increasing the capacity, advancing the timing etc etc and because its easy and you know a new one is not and original full of 46 years of gunk (not that it is if you have a 1500 as I presume that's been lifted out of something else at somepoint?)

if you are splitting the case, then a mild cam would go well with the twin carbs and ported heads

 

[BJ1]

Why do people fit 1641 conversions? There is NO measurable increase in bhp over stock 1600 barrels and pistons. That info comes from a rolling road that has tuned many aircooled motors.

Stock 1600 B & Ps are cheaper and stronger and with twin carbs (ICTs or IDFs) will push out enough power to make a big difference to the way the bus drives.

Which ever way you go, make sure the bottom end on that 1500 is in really good nick. Putting bigger B & Ps and twin carbs on a worn bottom end is one of the best ways to kill an engine.

 

[Marshy]

Was looking at sorting a new camshaft first, vwh do a package with lifters and wheel, c25 or c35? And are they any good?

 

[jonboylaw]

One word, heads. If you are keeping the single ports and associated tinwear then do sort the heads out, it will give you the best gains. Thorough de Coke, new exhaust valves, some flowing and proper seat cut will see more gains than umpiring the CC by 43cc.


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[Marshy]

Done some cleaning on the heads as pic but sure not enough
Was looking at twin ict's also, and quick question, will these work with vac advance?

 

[BJ1]

Most ICTs have a vac take off that is OK for an SVDA dizzy but will not give the right advance on a single vac dizzy like those fitted to stock 1500 and 1600 single port engines. Contrary to the stuff you read on forums, genuine 009 dizzies also work well with ICTs.

 

[jonboylaw]

Check the guides for wear, worth replacing as the heads are stripped.


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[jonboylaw]

Does anyone have an old 1600 SP head they could donate to me? It can be quite scrappy. I'd like to test it in my flow bench and compare to twin port for a de facto answer, then try flowing it


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