Turbo/supercharging project

Competition engines and 'live' projects only. Good photos to illustrate your post are expected.
Post Reply
bialbero-racing
Posts: 5
Joined: September 12th, 2006, 9:31 pm
Location: Norwich, England
Contact:

Turbo/supercharging project

Post by bialbero-racing » September 17th, 2006, 7:09 pm

I am looking into a way of fitting both a supercharger and turbocharger on the same engine, the idea is to mount the turbocharger away from the head at the end of a four branch manifold, this should help the engine breath better, then run a supercharger to compensate for the lack of boost down low. The supercharger could be made to produce it's boost earlier by changing pulley sizes.
I idea is to have which ever unit is supplying the greater boost feed the engine via some sort of demand valve?
If I used an already turbocharged engine would the ECU be mapped for a boost condition lower down the rev range.
I am not looking for great gains in the total BHP produced just the additional Torque lower down with out losing out top end.

Guy Croft
Site Admin
Posts: 5033
Joined: June 18th, 2006, 9:31 am
Location: Lincoln, UK
Contact:

Post by Guy Croft » September 18th, 2006, 5:33 am

Well, the two boost devices differ in that the supercharger gives a speed sensitive boost response and the turbocharger boost is load sensitive, and the turbo engine ecu is mapped up for the latter, so, no I would not expect the fuelling to be right for both.

GC

SteveNZ

Post by SteveNZ » September 18th, 2006, 7:10 am

Can you let us in on more details? Engine, turbo and supercharger you intend to use? how much power do you want, and boost at what RPM? Also what sort of budget?

Given you want to run a standard ecu and engine, I assume your budget would be quite low. This is not really a low budget project. This is a massive project to say the least. Phasing the 2 chargers can be difficult even with a healthy budget. Most manufacturers dont even make a good job of it.

At the end of the day, is it all worth it?

Julian
Posts: 181
Joined: June 22nd, 2006, 6:45 pm
Location: Manchester, UK
Contact:

Post by Julian » September 18th, 2006, 8:09 am

In terms of the mechanicals behind what you are trying to do it is all available pretty much off-the-shelf from the VAG parts bin. You would still need to provide a suitable map and various fabrications to make it fit your car but the really tricky bit has all the work done for you already.

The parts are all pretty new still so I couldn't comment on cost or availability.

Traditionally the biggest hurdle was providing a smooth transition from supercharger to turbocharger. Abarth solved this with a rather clever clutch mechanism but it took them a long time to get it right. The important aspect is that there isn't any shock in the boost pressure as it can be very destructive to the turbocharger.

bialbero-racing
Posts: 5
Joined: September 12th, 2006, 9:31 pm
Location: Norwich, England
Contact:

More details

Post by bialbero-racing » September 22nd, 2006, 5:29 pm

Thanks for the information

The fine details has not yet been worked out. I am looking to use Fiat/Lancia parts where possible.

As for base engine I have 8V 1600 & 2000 turbo engines I also have a 16V integrale engine.

The original intension was to use the VX supercharger but with secondhand BMW mini units being so cheap I think this could be a better unit.

I am not opposed to buying an aftermarket ECU.

As for smooth pressure change the original intension was to have a simple reed valve on the engine side of each charger but I feel this will just cause the unit not winning the pressure war to stall. It might be possible to use that system and fine tune a bypass/blow by to prevent supercharger stall. this would only dump compressed air as fuel is not added until the inlet manifold.

For Power I would be happy with 250/300BHP which is not much better than the original Integrale unit and I don't need the torque as the target weight is only 650Kg (this was the weight of the original car I hope to fit the engine into) It just a engineering problem I would like to solve.

I planned to back the engine with a Lexus/Toyota 6 speed gearbox or the Tremec 5 speed I already have.

Guy Croft
Site Admin
Posts: 5033
Joined: June 18th, 2006, 9:31 am
Location: Lincoln, UK
Contact:

Post by Guy Croft » September 23rd, 2006, 5:42 pm

Lionel, dump the turbo.

Supercharge the 16v.

GC

petert
Posts: 61
Joined: July 13th, 2006, 12:38 pm
Location: Sydney, Australia
Contact:

Post by petert » September 24th, 2006, 2:38 am

So long as you choose an ECU that can sense load via manifold pressure, I can't see why you can't supercharge and turbo at the same time. With Haltech ECU's for example, it's possible to fit 1 Bar, 2 Bar or 3 Bar external MAP sensors. So mixtures at different load /RPM sites would set according to the nett total of the two boost systems.

bialbero-racing
Posts: 5
Joined: September 12th, 2006, 9:31 pm
Location: Norwich, England
Contact:

Post by bialbero-racing » September 25th, 2006, 9:49 pm

Hi Petert
would this not take me back to the first question. If my current turbo ECU is load sensing from manifold pressure and throttle position, how would it know where the pressure came from and why would is care.
The only thing I can think of is that the factory did not populate the ECU with a full set of curves and so for boost at lower RPM than the turbo would normally run it reverts to a nominal/background map.

I like Guys idea of just putting a blower on the 16V lump, but if the above is true then it to will need time on a rolling road setting up an ECU.

Lionel

Guy Croft
Site Admin
Posts: 5033
Joined: June 18th, 2006, 9:31 am
Location: Lincoln, UK
Contact:

Post by Guy Croft » September 26th, 2006, 5:44 am

Lionel hi

you need to make the call here as to whether you do one system or use both, because to get to the 250-300bhp it's going to need a different ecu setup and maybe injectors too whatever you do. Running both boost sytems will double the complexity of the architecture as well as the calibration, whereas either super- or turbo-charging could easily take you there on its own.
I am prepared to give the twin setup some thought but you need to make the decision first.

GC

G&G Motorsport

Post by G&G Motorsport » September 26th, 2006, 6:01 am

Hello all
This is my first post on GC

I have been reading with some interest this thread.
I can tell you all that when done properly a dual charged engine is totaly awesome, I have recantly mapped and been involved with the latter end of developing such a system.

The torque is just there all the time, as soon as throttle is opened( I mean as soon) there is positive boost, but un like anti-lag the vehicle drives nicley too.

Good to be here

Phill

Post Reply

Who is online

Users browsing this forum: No registered users and 2 guests