Old vs New Turbo systems

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Subterfudge

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I'm new to turbo chargers but have heard about the 'ketchup effect' which older vehicles seem to have.

I have a 504 ti with FAG Kugelfisher MFI and would like to keep the all mechanical system

From what I understand, modern turbos are electronically controlled to smooth out the boost

So then would there be much performance difference between an older and more modern turbo system if neither are using an ECU? and is there any way to get more modern performance from an older turbo without compounding?
 
Hi Suberfudge :giggle: :whistle: welcome .
I am no expert on turbos or 504ti but here are my thoughts. Putting an old style turbo on your car will increase the air flow into the engine without doubt and the boost control valve will work OK to limit it to what ever it is set to. BUT just putting more air in will not make more power. You need to put more fuel in to make more power and the extra fuel needs to match the extra air so the engine is happy and does not burn up vital internal parts. Put very crudely :rolleyes:

I would doubt there is any information and expertise on modifying the Kugelfisher mechanical injection system to work with a turbo to get the extra fuel at the correct A/F ratio. There is your problem IMHO. You can research modern EFI systems on the web to find out what to do but with your old system you will be on your own and will need a high level of knowledge IMHO. Hmmm o_O
Jaahn
 
jaahn said:
Hi Suberfudge :giggle: :whistle: welcome .
I am no expert on turbos or 504ti but here are my thoughts. Putting an old style turbo on your car will increase the air flow into the engine without doubt and the boost control valve will work OK to limit it to what ever it is set to. BUT just putting more air in will not make more power. You need to put more fuel in to make more power and the extra fuel needs to match the extra air so the engine is happy and does not burn up vital internal parts. Put very crudely :rolleyes:

I would doubt there is any information and expertise on modifying the Kugelfisher mechanical injection system to work with a turbo to get the extra fuel at the correct A/F ratio. There is your problem IMHO. You can research modern EFI systems on the web to find out what to do but with your old system you will be on your own and will need a high level of knowledge IMHO. Hmmm o_O
Jaahn
Click to expand...
Adjusting the MFI is no issue, I rebuilt the thing



I'm looking to get modern performance without needing an ECU to control the turbo. I haven't messed with turbos enough to know if this is possible and I'd like to know before spending money on a brand new turbo that might end up performing like one from decades ago
 
I personally think that if you use technology from decades ago that is the performance that you will have.

The reason why everything is controlled by electronics is that it is cheaper and more adjustable and adaptable than the old mechanical gear.

Not saying that you can't put something together that will work, but like Jaahn has said that you are going to be on your own doing the research and development.

Still would be an interesting project and you seem to have a good grasp of the FAG Kugelfisher MFI fuel injection system.
 
COL said:
I personally think that if you use technology from decades ago that is the performance that you will have.

The reason why everything is controlled by electronics is that it is cheaper and more adjustable and adaptable than the old mechanical gear.

Not saying that you can't put something together that will work, but like Jaahn has said that you are going to be on your own doing the research and development.

Still would be an interesting project and you seem to have a good grasp of the FAG Kugelfisher MFI fuel injection system.
Click to expand...

I'm an engineer rather than a mechanic see, so was happy to fiddle about with the thing for a solid month haha ECU's go right over my head though... never much cared for programming.

Sadly, I have zero clue about modern turbos - besides knowing the basic principal of how they operate.

Was hoping to get quite a bit more 'juice' from this XN2. I had gotten rather hopeful after reading various posts on this forum but most people do seem to rip the MFI out entirely

The MFI system was installed on a lot of various vehicles though so I'm hoping someone somewhere has tried...
 
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I found this for a BMW 2002, not sure if you have seen it before but may help you.

www.bmw2002faq.com

Kugelfischer / turbo question

Searched but did not find a definitive answer. I am looking into whether or not the stock tii pump will be able to be tuned to handle the demands of a small turbo. Maybe 8psi with an intercooler. Possibly from a saab 900. I know the bosch mechanical pumps would work because they could be richened...
www.bmw2002faq.com www.bmw2002faq.com
 
Hi Subterfudge.

I think you have received the general flavour of your answer already.

I don't have specific knowledge about your application so can't offer any assistance. But I have some comments.

The trouble is that after driving modern vehicles with variable nozzle turbochargers and multipoint fuel injection, VVT, electronic ignition and many sensors providing feedback to the ECU that micro adjusts all of the parameters in real-time, they just work smoothly and seamlessly. Negligible lag, very good drivability, good power when you want it and good fuel economy when you are cruising.

Retro fitting a mismatched turbo onto an older vehicle that requires bespoke plumbing, mounting etc and limited pool of established knowledge to tune fuel supply, ignition timing for boost/no boost etc etc, will end up feeling very frustrating to drive. Sure you might achieve good performance when turbo is on song, but for the expenditure and time that will be consumed for a project like this I suggest the outcome and general drivability will not be satisfactory.

Different if you were retrofitting a turbo system from an engine that was a production option for your vehicle engine previously, as all of the calculations and thinking and dyno and road testing and modifications have been done by mechanical engineers that have the resources of a manufacturer and also prior applied experience.

It's your vehicle you can do what you like. But I wouldn't be doing it.

Cheers.

​

 
I suppose modern turbos have nice fancy wastegate control bleeds built in, and variable vane and sometimes nozzle control, but it will need a bunch of load sensors and ecu outputs to control... So since you dont have any of that. Just get a decent adjustable wastegate, and sort your fuel pressure to match.. Your fuel is cammed control so you can't really just push more pressure can you.. You will need to adjust the cam in the fuel delivery block? Ah well. Do the math and set that correctly and go nuts!
 
`There is some experience in matching turbo with KF MFI ( BMW Turbo ) and lots of experience matching it with supercharger ( ME 109 et al. )

It might be worth asking Koller and Schwemmer (Hermann Sattelberger ) in Nuremeberg about specifications and availability of the „Klotz“ ( internal 3D cam ) which regulates mixture v. Throttle opening/Load, also about how they tweaked the vacuum control of mixture on the KF6 to make it work with boost.

When I was in the shop picking up my KF2 they had a variety of MFI setups in for servicing as they are still used in a lot of hysterical racing ( Porkers, Beemers, Capris etc ) My guess is that you will not be the first to have grappled with this

Porsche used MFI on high end race cars well into late 90‘s because at the time it was very tunable ( if you had the bits and know-how ) EFI has these days made it lots easier, at least if one understands computers, and the advice to either leave alone or use EFI is very sensible, but MFI can still do a lot If you have the urge and the pain threshold.

Good luck

Andrew
 
The biggest problem with MFI is getting enough fuel in with the right progression, when the boost is up. Back in the day with our BMW turbo race car in the early 80's using MFI, we had a different cam in the injection pump, running at higher than standard pressure which was fed by a high volume/ high pressure Bosch race fuel pump. The MFI pump was modified by the guy doing the Benneton F1 engines at the time.

We also had a water injection system running a tank pressurised by the boost pressure from the inlet manifold. When the boost pressure went over 12 psi it operated a solenoid that opened a water injection nozzle that fed the pressurised water mist into the turbo inlet.

That water injection could become alcohol injection if you added a certain percentage of alcohol into the water. That solved the problem of getting enough of the right juice into the engine on full boost.
 
Hi well Col put a good reference to give some answers. Read that.
BUT people talk about one extra injector for extra fuel. If you run say 8PSI boost then simply put you need 50% more fuel to match the extra air !! Not just a bit of an extra spray in somewhere. And can you say the KF system can supply 50% more fuel and the injectors too.
There were lots of tricks I read about from the old days to get more fuel in to match the boost but it is all old technology. I never did any of that.
Dual diaphram pressure regs and things like that spring to mind. Get some old books is what I might do. But remember that running petrol engines lean(not enough fuel) at full power for any time will eat up the valves and pistons as will pre-ignition/detonation caused by excessive combustion pressure. :rolleyes:
Jaahn
From Col's link; NOTE 15 year old post !
Hi Zachary,
The tii hp kit we install is very simple. This will correct the air/fuel ratio on modified tii engines. Bigger cams require a non-linear fuel increase above 4000 rpm. Adjusting the Grub screw on the pump for more fuel will create a linear fuel increase which will reduce power at the low and mid range. We install a hand made link to the pump throttle lever that acts on the Grub shaft which is externally adjustable with small shims. All of our pumps are bench tested at various throttle positions and engine speeds. We calibrate our pumps to less than 1/2 of 1% differential between cylinders.
We have been so busy with other mechanical pump projects and racing that we never seem to find time to advertise our services to the tii folks. But we have a high regard for the KF pump and we have done a good number of stock and hp units. So please let your friends know about us. Some day we will add a page on our site http://www.wesingram.com.
Thanks, Wes Ingram
 
Andrew Watkins said:
`There is some experience in matching turbo with KF MFI ( BMW Turbo ) and lots of experience matching it with supercharger ( ME 109 et al. )

It might be worth asking Koller and Schwemmer (Hermann Sattelberger ) in Nuremeberg about specifications and availability of the „Klotz“ ( internal 3D cam ) which regulates mixture v. Throttle opening/Load, also about how they tweaked the vacuum control of mixture on the KF6 to make it work with boost.

When I was in the shop picking up my KF2 they had a variety of MFI setups in for servicing as they are still used in a lot of hysterical racing ( Porkers, Beemers, Capris etc ) My guess is that you will not be the first to have grappled with this

Porsche used MFI on high end race cars well into late 90‘s because at the time it was very tunable ( if you had the bits and know-how ) EFI has these days made it lots easier, at least if one understands computers, and the advice to either leave alone or use EFI is very sensible, but MFI can still do a lot If you have the urge and the pain threshold.

Good luck

Andrew
Click to expand...
May have to jump over to some Porsche and BWM forums to see if anyone still has some info on boosting the old 2002 or 911 with KF
Perhaps there's also some Lancia fanatics that could shed some light

Thanks for informing me of Koller and Schwemmer, until now I had only encountered a chap in the Netherlands doing rebuilds (but for 5500 euro a pop...), I'll have to contact K+S and see if they're willing to chat

Don't mind the supercharger route, just as long as I can make enough power to justify the expenses. Just figured turbo would be better with the XN2 given the low compression ratio
 
K and S are the official agents, with all the tools etc

They did my KF2 for about $4K but I have had grief with it since, now sorted after much fiddling. When mine was in Hermann was off sick so it was done by a junior, which may account for this

The chap in Netherlands was politely scathing about K and S when I discussed my issues. Not sure whether it was commercial rivalry or a balanced assessment

For advice I think that Hermann would be a good bet, as I think he does a lot of the race stuff.

If you need anything done, Nottingham Diesel Services in UK are very helpful, have done some small stuff for me, and are well spoken of by Mike Tippett on this forum. They seem to be cheaper than the Germans/Dutch

Best Wishes

Andrew
 
Won't work, the injection system on the 504 is configured to work on a vacuum, no provision to work on positive manifold pressure. The earlier 404 system may work as it uses throttle position. Modern MAP sensors will work on both vacuum and positive pressure. You need to fit a fuel rail with EFI style injectors, different sensors and an aftermarket ECU.
 
The BMW 2002 TURBO is fitted with a different Kugelfischer pump to the 504. Google, BMW 2002 Turbo kugelfischer/ "Images".
 
I rebuilt the KF without spending £5.5K as quoted so I think I'll figure out how to boost it just fine without pedantises, thanks
 
Be sure to keep us informed as to your methods and progress, I might like to Turbo my Ti. Another 60 0r so HP would be nice. :)
 
....because the thread was asking about new "modern" turbo's, not about KF tuning.
 
Bowie said:
....because the thread was asking about new "modern" turbo's, not about KF tuning.
Click to expand...
But he is trying to use KF system with a turbo? Would possibly work with the 1.8 504 or the 404 systems which use mechanical load sensing, not vacuum. 2 litre went to vacuum for load sensing due to emission requirements apparently.
 
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