Twin 45/48 carb set up??

Hey oop..

Wandered if anyone's sitting on a twin 45 or 48 carb set up for a 1.8dx?
Weber's, Dellortos?
Ideally with a manifold..

Looking to ditch the bike carbs.. 

Happy Sunday. 

You'll also be ok with twin 40's if that helps broaden the search at all.

Be careful with Webers as many of them are vehicle specific.

I prefer Dellortos personally.

Ian

borednow said

You'll also be ok with twin 40's if that helps broaden the search at all.

Be careful with Webers as many of them are vehicle specific.

I prefer Dellortos personally.

Ian

Thanks for the info, pal..

Out of interest do you know what the overall performance difference is between the different sizes?

I don't suppose you have any experience of running an 8v crossflow head vs a counterflow with carbs? 

Thanks.

I do, but different engine sizes!

I have twins on my 1272 cross flow in my Derby, my Bro in law has twin 40's on his counterflow 1.8 and I have bike carbs on y 1400 16v DOHC cross flow.

It depends on the cross flow engine. Some are more BHP from the factory. There's a KR code and another one, both cross flow. one was 150 from the factory on injection and one was about 120. Sorry can't remember which.

The difference in the carbs is the chamber. The problem is with a 45 or 48 on a 1.8 counterflow is that you have to use such small jets otherwise you'll just be sending too much fuel/air to the engine.
40's are perfect for a 1.8, as they were designed to go up to 2 litres and around 180bhp with no probs.

If you're planning on boring out the block and adding ridiculous cams and things then 45's might be needed. but for a bit of 'tuning' then 40's will be fine.
Bro in law is registering around 130bhp from the counterflow engine. An increase of around 35bhp from the original 95bhp of the 1.8 carb engine. He did go with a GTI head which he blanked off the injector holes on as well though. Apparently the cam is little peppyer in the GTI

When I got 144bhp from 1400 on bike carbs he was a little miffed to say the least  

Obviously getting them jetted and set up properly is a must.

Anything else give me a yell

Ian

Brilliant!!

144 on bike carbs from a 1.4!? Good effort, my 1.8 made 136, fast road cam and a couple of other bits. How'd you do so well? 

I was thinking, more daydreaming, about rebuilding my engine (it need to come out to paint the bay) I've got some cool bits for my 8v, rennsoport rocket cover and JM racing engine mounts, exhaust mani and some other bits I'd like to hold on to. So I was thinking a board out 8v (ahh?) 2.1 with a cross flow head and twin carbs. 

My bike carbs where set up well, but aren't performing as well as they used to, saying that I've done some little bits, new throttle pedal bush and the engine mounts and it's a lot better, mot found the rear mount was shot so under fruity pedal work the exhaust was pulling it self away for the c/head. 

But if I'm not going to see much of an increase I may as well hold off. Like I say I was seeing around 135bhp with the bike carbs, maybe I'll get them retuned, do you know anywhere? 

Thanks dude!
N

borednow forgot to quote you! 😂

BIGNICKC

Quoting helps as I tend to wander about a lot doing Mod stuff and sometimes forget to go back to topics  

My little engine was completely rebuilt. I had two of them and they were both rubbish so the engine company ended up using the best of the all the bits I had then completely re-built it back to VW specs, except for a bit of an overbore due to issues with the bores (but only a fraction of a mm so slightly larger piston rings) the head was tested, skimmed, gas flowed and again rebuilt with new guides, springs etc.

It all cost a bit (well a lot tbh and much more than I was expecting £1650 or there abouts)

Apparently the 1400 has a better flow rate through the head than any of the other vw engines and it is a twin cam so that helps too. Problem is that all the powers at 6800rpm! At around 3500rpm I've only got around 90bhp so it's all a bit of a trade off tbh. I have to change out of 5th on the hills on the A30 down in Cornwall as it hasn't got the guts to pull itself up in 5th at 70mph. However in 3rd it'll accelerate up the same hill as if it's not there!

I believe you can use a 2litre long block from a mk3 on the bottom of an 8v head and it's supposed to add torque (more displacement I suppose) thus making it more drivable.

The cross flow head will definitely help. It's on my Bro's list of things to do as was a 2l bottom end.

There's a guy running a sprint/hill climb car with an 8v in it running over 200 bhp on carbs so it is possible. Have a google and a search through Youtube. Can't remember the guys name though, sorry.

The guys that did mine are RK Engineering, he mainly does chip tuning and ECU stuff but as a favour did mine. He then rembered why he doesn't do carbs anymore!    He got werll miffed with taking them off, drilling out jets, putting them all back in again etc etc etc.

Might be worth giving them a good clean as they do tend to bung up quite easily.

A good rebuild and matching all the ports to the manifold etc will all aid in hp. It's one of those incremental things i think.

Better ignition 5hp, port matching 3hp, better matched exhaust 4hp, baffled sump 2hp, better fuel 1hp, and there you go you've just added another 10hp just by fiddling.

You seem to get massive % gains by changing the carbs and exhaust then the rest is just how it's all put together. Depends on how much time, money and effort you want to put in I suppose

Ian

Hey Nick…

45's and 48's are for high spec road-race engines making 160-200+ hp. 45's can be run down to 145-150hp with 34mm chokes but below that 40's with up to 34mm chokes are fine to 140-150hp….or less power with smaller 32-33mm chokes. Not much power difference between crossflow heads and original style when both modded the same….crossflow heads flow more in standard form if it's the 2ltr version but not the 1600…lots of variations.

Weber and dellortos don't just bolt on though to the big block engines….they do physically but the manifolds need port matching to the heads (plus porting out if it's an old used one rather than a new better cast one)  which need to come off obviously to do it…if not you won't get the best from the carbs which is after all the idea in the first place.

I'm in Germany but I have two set of Weber 40 DCOEs. One set are off an old Alfa, Italian, model 27s. The other set are the new Spanish 151s. I have a box of jets, air horns, chokes, so I can set them up for your application possibly. Looking for 400 euro a set plus shipping. I ran the 27s for a year or so, upgraded to the 151s, pulled those last week for new 45s 152G. Message if your interested. I have an ultrasonic cleaner so I can toss them in the bath prior to shipping. I have a  thread over in the mk1 project forum.