Bike oriented V8 Turbo

[jimbob82]

so, the current plan has changed. Flat12 on hold for the moment, as per:

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

New plan as follows:

Using 2 cylinder heads from a motorbike engine I'm planning to create a V8 to bolt them on. I was originally thinking (yesterday) to run it N/A but thanks to Max_Torque's suggestion in the Flat12 thread I decided TURBO is gonna be waaaaay more fun.

Heads I'm looking to use are going to come from the BMW S1000RR -- simply because everyone who I have read about says they are THE best flowing heads for a production bike. So, I need to get 2 engines or at least 1 engine and another head for prototyping.

BMW S1000RR specs here:

http://www.motorcyclistonline.com/2012/bmw/s/1000_...

for those who cant be bothered to look

Bore = 80mm
Stroke = 49.7mm
CR = 13:1
DOHC 16 Valve
Displacement (Total) = 999cc
Power = 179bhp
Max power @ 13,250rpm
RPM Redline = 14,000rpm

I spoke to my brother earlier today because he is a bike mechanic and knows bikes pretty well. He reckons it's a phenomenal idea (think's I'm crazy) and an even bigger task "for me"...I don't think he meant it like that though, just typical older brother stylee.

Anyway, running the specs and flow data I can find, if I run 2 turbos (hybrid t2860rs but with a smaller turbine housing for the hot side) i'll be looking at somewhere around the 800bhp mark @ 10,000rpm. <- with lower comp forged pistons ofcourse

Couple of questions for the more knowledgeable (i know im a PITA),

The valvetrain in the S1000RR heads can safely do over 14000rpm stock so my question would be, do you think those stock springs can handle 10,000rpm with the boost (20psi)? or should I get some heavier/beehive springs made up?

I'd have to switch out the exhaust valves for - probably - nimonic valves and stellite coatings, do you agree?

On the crank side of things, keeping it flat plane, I think the best way to set it up subject to measurements/calculations is to run the 2nd bank 360 degrees behind the 1st bank. does this sound workable or would I be better off running the 2nd bank 360 degrees after but the opposite firing order (reverse the head)? I don't see there being a problem with the 1st way of doing it other than possible bad harmonics...

Should I keep the stroke stock or increase it to 60mm = 2.4 litre? <--- yes I love that number lol

do you think 800bhp is too much to ask?

as usual, all advice, help, criticism will be much appreciated.

[Tango13]

The first problem you're going to have is getting all the con-rods onto the crank as the cylinder spacing won't allow a longer crank to run the big ends on the journals side by side.

This leaves you two choices, a master & link rod set up which would almost certainly vibrate the engine to death at 10,000rpm or go fork & blade. Fork & blade will mean both the cam chains will want the same part of the crank for drive but this can be neatly solved by reversing one of the heads to run the cams from each end of the crank.

So if the I is the cam chain and O is the cylinders the top view will look a bit like...

IOOOO
OOOOI

The rest of it should be straight forward design and manufacture, well, as straight forward as it can be

Edited by Tango13 on Saturday 16th February 22:33

[jimbob82]

Tango13 said:

So if the I is the cam chain and O is the cylinders the top view will look a bit like...

IOOOO
OOOOI

The rest of it should be straight forward design and manufacture, well, as straight forward as it can be

this was one of my trains of thought yes.

with regard to the crank, subject to measuring the stock crank, I was hoping I might be able to fit it all onto 1 forged crank. if the mains allow for the room it's do-able by narrowing the webs/counterweights...but this remains to be seen

[jimbob82]

sorry for the DP. found a pic of the crank...



looks like there's gonna be plenty of room to run 2 rods on 1 journal if i get a good billet crank made with narrower webs/counterweights. the rods - i did find a pic of them but it eludes me at present - appear to be cast rods and quite soft so I should be able - if I need - to make the rods slightly thinner if I get H-Beam rods made up to allow more room on the journal sizings.

all looking fairly good to me at the momoent...

[one eyed mick]

Its's been done by Harris in the states and Paramount ? in england plus others . The Harris one is available to order ,around £20K paramount a sim fig 4/5 years ago . There's a guy in the states put a twin turbo Harris in an Aeriel atom reputably 600+hp must be mental google HRv8 for a video of prod processes and install in a Caterthing

[jimbob82]

one eyed mick said:

Its's been done by Harris in the states and Paramount ? in england plus others . The Harris one is available to order ,around £20K paramount a sim fig 4/5 years ago . There's a guy in the states put a twin turbo Harris in an Aeriel atom reputably 600+hp must be mental google HRv8 for a video of prod processes and install in a Caterthing

got any links? i caant find anything...where they done using the BMW heads or was it the normal BUSA jobby that many have done?

[one eyed mick]

As in my post Gooogle H1v8, it may also be on yu tube they use hyabusa barrels and heads cnc milled crank case and billet forged crank std rods I think also cams and injection for something around 300 hp but it will prob take any bua eqpt for more !

Edited by one eyed mick on Sunday 17th February 15:02

[-Bladerider-]

LOL

Jim, as per my comments in the other thread...

You got your exhaust housing thinking the wrong way round mate, high revving engine with oversquare internals will equate to a zero torque low down response and hence having a restrictive smaller housing is counter productive, you will need the biggest housing you can get, which is why I suggested the GT28 in the first place !!

GT2871r will easily reach your 800bhp target but with only 1.2 litres to spin it round even with the long powerband it may be horrid to drive
GT2859-9 might be a better bet as they still have good top end, are fractionally smaller but require slightly less to blow em round so should spool a bit quicker while still not restricting revs

But personally I would be checking out the new variable vane options or billet wheel twin scroll units with anti surge and such.

J

[jimbob82]

yeh. it seems I do. Maybe best to leave the turbo side of it to the guys you recommended. Probably better to run 2 vane turbos as you say.

My thinking was that if the housing is slightly smaller it would spool quicker. Because I have seen T2 turbo's with T3 housings so they spool quicker but throw out more CFM than a standard T2. I suppose it depends on the application though, I guess at 10krpm it wouldn't be such a good idea - head lift is more than likely me thinks.

@one eyed mick

thanks for that - I was searching for HRV8 as per your original post. The H1V8 looks good but it's been stroked and it's using busa eqpt, I'm looking at using BMW heads so in this particular sense/instance it hasn't been done before.

I think best thing is to do what someone else posted, get the engine built and running lower compression so it can be boosted, then take it to a specialist as per Bladerider's post. I can just concentrate on the engine side then, instead of doing my usual and trying to do it ALL on my own. Much better to enlist the help of more experienced folk than FAIL miserably on my own.

[-Bladerider-]

Dont know where you are or if it helps,

Friend of mine owns a bike breakers !!

Has supplied me various engines for projects in the past - busa, new gixxer thou etc

He is near Romford so he could be asked to keep an eye out for BMW lumps if you wish.

J.

[jimbob82]

-Bladerider- said:

...he could be asked to keep an eye out for BMW lumps if you wish.

J.

mate, that's awesome if you could ask him, I don't mind if they're U/S completely knackered, only need 1 to get measurements and stuff like that so even if they've thrown a rod out the side or smashed the pistons it won't matter for R&D purposes

[-Bladerider-]

okay matey.

[GavinPearson]

With respect to the valvetrain, the system is designed to work with the OE exhaust that has a certain level of backpressure. Of key relevence is the actual pressure in the ports, as this acts on the valve head and provides resistance against the spring.

In a turbocharged application, the backpressure is going to be far higher in the exhaust ports than an n/a engine. The more boost you run, the higher the pressure. You need to know that pressure in order to figure out the spring pressures required to seat the valves.

With respect to the valves, the material spec really depends on the temperature the valves will see. This is a function of how long the valves are in contact with the seats, the seat material and cooling characteristics of the head. An easy way out is to use beryllium copper seats and the highest temp spec valves you can buy, flow a great deal of coolant and then hope for the best.

A key issue with converting an NA engine to forced induction will be the rise in cylinder pressures. You will need to think about having a gasket than can handle the peak cylinder pressures and a clamping system that can hold it all together.

It would be a great deal easier to make a W12 NA than a turbo V8 as it would massively lower the amount of engineering work, IMHO.

[dom9]

GavinPearson said:

It would be a great deal easier to make a W12 NA than a turbo V8 as it would massively lower the amount of engineering work, IMHO.

Would require a longer crank though, I suspect?

I remember a paper on a theoretical design for a W9 that was pretty cool: http://epubl.ltu.se/1402-1617/2006/099/LTU-EX-0609...

[-Bladerider-]

Jim,

Got to speak to my pal who is a very experienced top level former racer, bike dealer and owned a bike breakers as I mentioned. He has also spent huge sums racing and modifying cars.

He tells me that the BMW lump is probably not the place to begin with for numerous reasons which I wont go into detail of here.

His best recommendation would be the GSXR1000 engine for a mix of component reliability, tuneability and so on. He is keeping an eye out for one for you.

J.

[jimbob82]

dom9 said:

Would require a longer crank though, I suspect?

I remember a paper on a theoretical design for a W9 that was pretty cool: http://epubl.ltu.se/1402-1617/2006/099/LTU-EX-0609...

a W12 is pretty much the same size as a v6...

bladerider, does he know i'm turbocharging it? and can you gimme his number? maybe i could have a quick chat with him 1 day. ty

[GavinPearson]

dom9 said:

GavinPearson said:

It would be a great deal easier to make a W12 NA than a turbo V8 as it would massively lower the amount of engineering work, IMHO.

Would require a longer crank though, I suspect?

I remember a paper on a theoretical design for a W9 that was pretty cool: http://epubl.ltu.se/1402-1617/2006/099/LTU-EX-0609...

So this is where the benefit of experience helps..... it's one thing to put something to paper, but it's another to have a team of twenty engineers spend 3 to 4 years each develop the engine and make it production ready.

The key part is knowing that the combustion system is sound, that the parts are adequately reliable. When you double or triple an engine up your calculations and validation are limited to the stuff you changed, add a turbo and now you need to revalidate the bearings, head gasket / joint system, cooling, develop the combustion et cetera et cetera - a massive amount of work.

The engine might need a longer crank, it might need two or three cranks. But that is far easier to do than develop a turbo combustion system, size the turbos etc etc.