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Big one or little one?!

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Have just bought a 16v gas flowed head :D I’m going to be port matching the inlet manifold myself, but was wandering which one to match?! I’ve got the 50mm on the car at the moment, and the smaller one sat on the shelf :?

 

I seem to remember someone saying you got better air speed; thereby promoting torque through the thinner one – Is that right – have I just answered my own question :oops:

 

Turboing is a real possibility in the future too :twisted:

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small one will give you mid range, at the expense of top end flow.

 

big one will give you top end power, at the expense of mid range torque.

 

 

your call. I'd go for the mid rnage over top end any day if it's a daily car. if it's a weekend racer, then go for top end power.

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I’ve got the 52mm on the car at the moment, and the smaller one sat on the shelf :?

 

It's 42mm and 50mm respectively!

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It's 42mm and 50mm respectively!

 

:oops: ......duly edited

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the 42mm one came stock on all of the US cars. i think you might be better off with the 50mm. i just got the 50mm for my car. hopefully by the end of the week i will finally have it running. use the one you think will apply best to how you will be driving. 42mm for more mid range and the 50mm for more top end.

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Ive converted mine from 42mm to 50mm thenback to 42mm again.The corrado is heavy and has crap gear ratios compared to the golf 16v and i have 17s so this throws the acceleration out the window.When i switched back to the 42mm one i noticed a big increase in overall torque and the car is much more fun to drive now

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have to agree with that, i noticed that my acceleration and general performance of the car suffered after fitting the bigger inlet manifold. its likely i will be changing back to the smaller one next time i see one up for grabs

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cheers - will be opting for the smaller bore at this stage, means i can get cracking straight away :D

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I found 10lb/ft torque using just the 42mm manifold on one of my Golf 16Vs. No loss of top end either.

 

You know how VW used to quote 0-60 in 7.3 seconds for the Golf 16V? Well it was true, but only on the C-D reg 42mm equipped cars. The later 50mm cars did 60 - 7.8. The incremental times for the 42mm valver were better too. I've got an Autocar mag from 1987 featuring a head to head with a Golf 16V and the Pug 309 1.9 GTI - a known, torque car with good handling (better than the 205).

 

The Golf killed it in all key areas 8)

 

K

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I found 10lb/ft torque using just the 42mm manifold on one of my Golf 16Vs. No loss of top end either.

 

You know how VW used to quote 0-60 in 7.3 seconds for the Golf 16V? Well it was true, but only on the C-D reg 42mm equipped cars. The later 50mm cars did 60 - 7.8. The incremental times for the 42mm valver were better too. I've got an Autocar mag from 1987 featuring a head to head with a Golf 16V and the Pug 309 1.9 GTI - a known, torque car with good handling (better than the 205).

 

The Golf killed it in all key areas 8)

 

K

 

it would be good to get a variety of torque plots together for the 42.5 and 50mm manifolds on different engines, (even if there is a margin of error in rolling road plots)

 

here is my 2.0L bored KR block with KR cams and an internally polished and ported 42.5 inlet

and secondly the engine as it started out, unmodified 1.8 KR with a 42.5mm inlet

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I've got the 50 mm one on mine now and it has absolutely no torque until about 4300rpm, its like waiting for the turbo to kick in, i was actually considering putting the wee one back on but i've had the big one powder coated and it looks all pretty, decisions decisions :roll:

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I've got the 50 mm one on mine now and it has absolutely no torque until about 4300rpm, its like waiting for the turbo to kick in, i was actually considering putting the wee one back on but i've had the big one powder coated and it looks all pretty, decisions decisions :roll:

 

Internally polished(rough, not a mirror finish) and port matched 42.5mm is the way to go IMO, unless the engine is race spec in a mk1 Golf track car

 

David.

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The intake ports where the manifold joins to the head are of a smaller cross sectional area than the smaller manifold, so unless you have much larger ports than standard, I can't see there being an advantage with the larger intake manifold.

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The intake ports where the manifold joins to the head are of a smaller cross sectional area than the smaller manifold

 

Didn't think they're was any difference between the standard intake/ head ports - They're definitley the same size on this particular head, so must have been matched then polished :D

 

Made my mind up though - definitely going with the smaller manifold.

 

Cheers everyone.

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