BMW 16V TT Racer
Turbo Mini Forums

This looks very interesting and I am sure that the maths supports it. But surely 2 turbos on half the cylinders must be very similar to one bigger turbo on twice the cylinders. I understand turbo speed and such. It will be very interesting to see how it goes.

http://www.twin-turbo.co.uk
http://www.hillclimbandsprint.co.uk/default.asp

A man without a project is like a like a woman without a shopping list.

Hmm its about time someone tried a twin turbo.

1/4 Mile 14.3secs 96Mph Terminal 10psi of boost.


Fibreglass Parts? - http://www.tdkracing.co.uk/
Split Rims? - http://www.force-racing.co.uk/

Looking good, im not up on the maths and that but it looks fun anyway

Cant say ive seen too many twin turbo'd minis so good to see something abit differant! good luck ;D

The maths is really quite interesting and I encourage anyone who is interested to give the maths on this one ago. I was really amazed at just how much these K heads flow. They really make for such a clean burn the energy at the exhaust port is really quite something for people to under stand this a little better think of this as not one engine with 4 cylinders but rather two engines with 2 cylinders with a common crank things become a lot clearer if you brake it down this way. About 4 years ago I was involved with a project where we fitted a turbo to a CBR 660 cc bike engine and we had resounding success than a year after we Twin Turbo a Kawasaki ZX-900 again with fantastic success, when I was talking with some folks at TD a suggestion was made about the idea of a twin GT 15 setup and the die was cast.

I admit to thinking at first that it was a silly idea.

However, having had a look at the GT1544 compressor maps and the potential airflow on a high spec K1100 engine, then it starts to make sense.

But, your pulses are going to be odd due to the firing order. I would have joined the inners and outers to get pulses at 360 degrees. With this setup you are going to get two pulses 180 degrees apart and then a gap of 540 degrees.

I have heard an arguement that this will spool the turbine quicker but I'm yet to be convinced.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

well i think it`s a great idea,,, But i also believe in splitting the system a bit different, but either way the idea is wicked & i agree,,, just a plumbers nightmare & an R&D cluster Phuck to get it all right,,, but i see absolutely no reason why it wouldn`t work very well indeed,,, & the it`s just the added stuff around, bulk more time/money & the extra weight that makes me wonder about it`s Worth

but still,,, keen to se some results whn you have it all sorted

& for the fella questioning the firing order,,, One word---> Ford Escort/pinto among many other 4 cyl production engines with this very same firing order

www.miniman.com.au

"""LazyGoodForNothingSmartArseKnowItAllBackYardMiniMechanic"""

this is the only area Im no 100% sure on Paul, the only thing paul is the gap interval is only 360 not 540. My idea is to brake the plenum into two so turbo 1 feeds cyl 3 an 4 and turbo 2 feeds cyl 1 and 2, this should meen the the will never be a boost lag for a cylinder the turbo not on boost will be on a closed inlet valve thats the theory I am still doing the sums on that tho.

Very interesting.

I recon that one well chosen modern turbo would be as good and save lots of weight though.

IMO two turbos should be used for packaging reasons (i.e a 'V' engine) or where capacity is too great for one turbo. Or (like the Subaru Legacy GT) staged turbos.

I'll be interested in the results, but it looks like ballast to me.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

There is no doubt about it will one well chosen turbo would be cheaper and would probably perform as well but there is allot of evidence to back that statement up, on the other hand is there any physical evidence to deny that maybe two small turbos won’t work, If there Is I would be very interested to see as of yet I have not found such evidence and so I am going to run the trial my self.

As it stands total weight is 100g heaver than that a fixed length manifold and GT28 where the weight could come in is in the split charge cooler and piping we will see.

Hello hello!!


Ahh im back in action, im not sure what happened last night to my keyboard

Jean-what I was trying to say is that for some reason the bmw head cars have a different firing order

Nic, I can understand about the different order, but it still means that 1 should be paired with 4 and 2 with 3 as PaulS also mentioned if even pulses are desired. That may not be necessary if the idea that uneven pulses create a faster boost build up is true.

PaulH, I can't see how having each turbo feed 2 cylinders independently and paring them 1,2 and 3,4 will be a good idea. This seems to me like recreating a siamese port engine with a potential uneven boost between the cylinders.

Jean

http://www.jbperf.com/

how do you work that out Jean Im not with you logic, a Siamese engine has one inlet port for two cylinders we non the other hand have a trottle body and port for each cylinder there can be no cros port scavenging ??

paulH ,
in case it helps ,heres a 500 cc twin running a t25 , boost comes in at 3800 max power 9500 ish and max torque around 7500 on the rd

, this dyno sheet was with no flow through the intercooler ,so at 90mph odd its a bit more powerfull ,thats when it starts to lift the front wheel anyway ,

just to show it is possible ,even with a too big turbo to get boost in reasonably low down the range .
regards robert

Edited by robert on 7th Nov, 2008.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

http://www.twin-turbo.co.uk
http://www.hillclimbandsprint.co.uk/default.asp

A man without a project is like a like a woman without a shopping list.

just a megajolt would do ,and a connecting pipe to the map sensor to even the boost ... no probs ?.. having said that , i would run it common plenum .

Edited by robert on 7th Nov, 2008.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

http://www.jbperf.com/

http://www.twin-turbo.co.uk
http://www.hillclimbandsprint.co.uk/default.asp

A man without a project is like a like a woman without a shopping list.

Yes we most definitely did do this before Ben Ha I have been involved in some funny old projects in my short number of years.

We did run a mono plenum on the tt bike Ben we had a big problem with harmonic at the start though, we where runing a 1 and 4, 2 and 3 turbo arrangement when we changed to the 1 and 2, 3 and 4 turbo arrangement the harmonic went away this is why I have chose the current setup, I think for the sake of making things lighter I will run a mono plenum on this motor as well.

bear with me lads if my explanations are no interlay clear as I am understanding this as I go I am in uncharted waters with this one.

Thanks Robert It really is amazing that 500cc can spin the T25 up , the GT1544 is really quite a small turbo and as such there is not going to be any issues with them spinning up in fact my wore is that the may not be big enough to flow the demand of the motor on full chat the figures suggest it will but only time will tell.

I chuffing love that bike

would i be right in saying that to get say 20psi on a twin turbo setup each turbo wouldonly have to run 10psi? or am i being logical stupid?

Absolutly Loving it Paul keep up the good work mate... between you and Gary Ireland has now doubled in turbo minis LOL oh and I cant wait to see you dissapear off into the distance down the straight on mondello...lol

I think my bigest problam Mark is to try not Dissapear into a puff of smoke :(