Twin charged g40

[bbspolo]

Just wondering if any1 had ever tried this or thought about it?
Keep the g40 charger and add a turbo aswell??
Obersly gearboxes will be a problem if you start making 250-300hp but with the turbo not kicking in till higher revs having given it half a chance 2 get some grip maybe  it wont be that much more of a problem on the box??

I know of a yb that was twin charged a few years ago and they used a clutch on the charger that disconected it at 4000rpm, this being the revs the turbo was making good boost thus letting the engine rev to 8,5-9k and not having to worry about the charger blowing itself to pices??

Just a few idears that has poped into my head since ive had a weekend in bed ill! lol
Just intrested 2 hear what ppl think??

[Yoof]

Mapping & Packaging are the main issues, I'd love to have the time and cash to do it though...

[bbspolo]

But is it worth it..................... funny u say that as i had phill j or the phone 10 mins after posting that saying the same thing!

And the answer is proberly not.......... however im one of these ppl who likes the building, testing out new things rather than atchley driving the car!
So it would be more about just seeing how it would work, lets face it if u wanted loads more power easyly you whould just strap a bigger turbo 2 a 1341??

space i dont think would be so much of a problem as id just do what most the rst boys do and mount the turbo over the gearbox?

Yoof how differcult do u think it would be to map? problem i guess would be when the turbo kicks in and u have a massive boost spike 2 deal with!

Next question what turbo would u use?? say the target was 350-400hp?? IhI???

[Justin14100]

Next question what turbo would u use?? say the target was 350-400hp?? IhI???

I dont know intense amounts about these engines. But I do believe the most in the UK was around 230bhp?

would probs need a massive turbo, which would be laggy as hell
and a 1473cc 1w block. head restrictions would be huge at this point though.

if you have money to blow, it will make some interesting build threads!

[bbspolo]

If your gonna aim, aim high! lol
no this is all just talk no 1 is gonna do it! just the theory is intresting!
like u say id use a 1500cc bottom end, standard rods and crank (see how strong they rearly are?)
comp ratio .......... id say as low as high 7's??? does anyone make pistons as low as this??
Big valve head, cams etc
custom inlet manifold (some thing like this http://3.bp.blogspot.com/_fip_WjxItcI/STjyGWxP3OI/AAAAAAAAAaE/AEbVUTRDhSg/s400/DSC00051.jpg

Or even a 20v one?? They seem to flow very well even up 2 500hp?

[bbspolo]

This is ofcourse pretending a g40 gearbox could cope with 200hp let alone 350! lol

[Tommo]

You could spool a massive turbo if you had the supercharger, because the engine will be pumping loads of hot gas at low RPM.

If you wanted better cylinder head design you would be better looking at nissan micra or similar I would say, see what has a similar bore spacing.

You could run it through a carb and that would save any mapping ball aches.

Im sure there is a renault 5 turbo with 340bhp, and they arent even OHC. There must be people in germany knocking on for similar power on these engines surely?

[giorgio]

Most I have heard of is 240 out of a 1341 G, although I am sure a 1.5 will beat that.

Packaging in not that much of an issue. I think I could quite easily fit a turbo in my engine bay if I tried hard enough.

Probably easier to twin turbo than compound charge. Hmmm quad charged G...

[Yoof]

The mapping problem is the transition period- not so much the huge boost spike (as you coukld use an N75 valve to control wastegate duty) just point once the turbo is on song, and the relative ignition/fuel values.

I know AWT did a twin charged car, and from the videos it didn't look (or sound) massively smooth, but I've never driven it or been in it...

Merc using the M45 have electro-magnetic clutches on them to cut the charger at idle due to noise and emissions regulations, I suspect it would be possible to rig this up.

[pettsy]

I know AWT did a twin charged car, and from the videos it didn't look (or sound) massively smooth, but I've never driven it or been in it...

This one?

http://www.youtube.com/watch?v=BXnmGtdKgQk 

[Yoof]

That's the badger! Sounds insane 

[giorgio]

The mapping problem is the transition period- not so much the huge boost spike (as you coukld use an N75 valve to control wastegate duty) just point once the turbo is on song, and the relative ignition/fuel values.

You would have to have the turbo capable of equaling the SC before the SC efficiency starts to drop off.


Then through the use of you elctro-cutch ma-jig you can dump the SC (uses about 18hp at full wack apparently) and then using the N75 valve to regulate the transition.

Although I am assuming the clutch is not progressive so you the whole plan kind of falls down when you need to go back to the SC. Saying that you could leave the SC disengaged until its safe to bring it back into play but then whats the point of having it.

PS - that video sounds crazy. reminds me of this - http://www.youtube.com/watch?v=e-grRKVsOlU

Million internet points to the first person who gets their car sounding like this

Twin turbo makes much more sense.

[Andy]

Depends whether you're using the units in series or in parallel too. Series would be easier.

Either way, controlling and calibrating for transient events will be a pain in the arse to get perfect - certainly with Digifant! However, for the likes of us who're used to less than OEM levels of refinement, it'd probably be quite achievable to get something that worked.

One of my colleagues is building a compound-charged Golf at the moment. Be interesting to see how that turns out.

[giorgio]

Magnetic clutch


Somebody remind me why we own euro-shitboxes? I used to see the point but I have forgotten

[Tommo]

Why use twin turbo? Seems like a massive ball ache.

I would just get the thing to rev and then have a fairly big turbo on it. Fit a 16v cylinder head and get a bit of boost, should see you at 300bhp no bother I would have thought. Its been a while since I looked but IIRC there are plenty of people over 300bhp with A series minis with 16v heads on and turbos, but they are limited more by their bore size and stroke.

Somthing about the VW scene just seems to lack the performance developments that you see in a lot of other scenes, possibly because its a younger spread of people, or its more about cosmetics. Maybe its because VW didnt really make any cult performance cars like cossies, R5 turbo's etc. I suppose its too easy to upgrade to a 20v turbo.