|
|
Mar 18, 2015 18:00:28 GMT
|
I've been reading the K-Jetronic articles in the last few issues of PPC and something popped into my head:
Seeing as the system uses the volume of air flowing through it to regulate the amount of fuel which is metered to the injectors, would the addition of a positive-displacement supercharger (Eaton or similar) be 'relatively' simple? As the blower does no more than supply a set volume of air per revolution, the fuel side of things should be able to keep up (perhaps swapping injectors for ones from a larger capacity engine?)...
Would it then just be a case of monitoring the spark and possibly advancing it a smidgen?
*n
|
|
Top grammar tips! Bought = purchased. Brought = relocated Lose = misplace/opposite of win. Loose = your mum
|
|
|
|
|
|
Yes and no.
The air flow meter is only measuring the flow of air at atmospheric pressure, it cant see positive pressure. So just feeding boost into it wont work. What you can do is set the intake up so the supercharger sucks through the airflow meter, then pumps boost into the inlet manifold. That will be somewhere near to reading air flow correctly.
There will still be some small tweaking involved, and you may need a boost referenced fuel pressure regulator from an audi or volvo.
|
|
1988 Mercedes w124 superturbo diesel 508hp 1996 Mercedes s124 e300 diesel wagon 1990 BMW E30 V8 M60 powered! 1999 BMW E46 323ci project car
|
|
|
|
Mar 19, 2015 20:10:15 GMT
|
Yes and no. The air flow meter is only measuring the flow of air at atmospheric pressure, it cant see positive pressure. So just feeding boost into it wont work. What you can do is set the intake up so the supercharger sucks through the airflow meter, then pumps boost into the inlet manifold. That will be somewhere near to reading air flow correctly. There will still be some small tweaking involved, and you may need a boost referenced fuel pressure regulator from an audi or volvo. It's a positive-displacement blower; it doesn't do 'boost'; it just provides a higher volume of air. *n
|
|
Top grammar tips! Bought = purchased. Brought = relocated Lose = misplace/opposite of win. Loose = your mum
|
|
|
K-Jet ponderingDeleted
@Deleted
|
Mar 19, 2015 20:37:25 GMT
|
Cant see that working tbh. If you put it before the metering head its just going to push it down and overfuel .
|
|
|
|
|
|
Mar 19, 2015 22:01:15 GMT
|
It's a positive-displacement blower; it doesn't do 'boost'; it just provides a higher volume of air. *n Call it what you want, the end result is the same. Also you'll be wanting to retard the ignition timing, not advance it.
|
|
Last Edit: Mar 19, 2015 22:02:41 GMT by carat 3.6
1988 Mercedes w124 superturbo diesel 508hp 1996 Mercedes s124 e300 diesel wagon 1990 BMW E30 V8 M60 powered! 1999 BMW E46 323ci project car
|
|
|
|
|
Providing that the airflow meter/ fuel distributor unit is located upstream of the supercharger this will work perfectly well. It does need to be on the intake side of the supercharger though. K-Jetronic and turbocharging or supercharging can be made to work very well together very easily, and prior to the advent of affordable and reliable EFI/ management systems it could provide a relatively simple solution that avoided many of the issues with having to deal carburettors for blow-through use etc
K-Jet systems may largely have gone out of favour now and been largely superseded by electronic systems, but they can still be made to work extremely well with forced induction. On an older engine already equipped with K-Jet there is no reason that it couldn't be retained and tweeted to work perfectly acceptably in conjunction with a supercharger.
|
|
|
|
melle
South West
It'll come out in the wash.
Posts: 1,998
|
|
Mar 22, 2015 22:22:24 GMT
|
You might want to have a look at Saab 900 8 valve turbo engines.
|
|
Last Edit: Mar 22, 2015 22:22:44 GMT by melle
www.saabv4.com'70 Saab 96 V4 "The Devil's Own V4" '77 Saab 95 V4 van conversion project '88 Saab 900i 8V
|
|
ChasR
RR Helper
motivation
Posts: 10,241
Club RR Member Number: 170
|
K-Jet ponderingChasR
@chasr
Club Retro Rides Member 170
|
Mar 22, 2015 23:31:31 GMT
|
Or the Escort RS Turbo, and Porsche 924 Turbo cars . AFAIK on an RST the K Jetronic system is the same bar an electro fuel regulator adding in more fuel once the metering head reaches its limits in addition to the ECU dealing with the ignition (in the 924 this was a mechanical process until the later cars). AFAIK you can fiddle with the metering head to give you more fuel on boost but it is at the expense of overfuelling everywhere in the rev range.
|
|
|
|
melle
South West
It'll come out in the wash.
Posts: 1,998
|
|
Mar 22, 2015 23:44:52 GMT
|
Plenty pdf Bosch K-Jet manuals can be found through Google and downloaded for free.
|
|
www.saabv4.com'70 Saab 96 V4 "The Devil's Own V4" '77 Saab 95 V4 van conversion project '88 Saab 900i 8V
|
|
Smiler
Posted a lot
I no longer own anything FWD! Or with less than 6 cylinders, or 2.5ltrs! :)
Posts: 2,492
|
|
Mar 24, 2015 21:33:27 GMT
|
For anyone who might be interested there is a dumbed down guide on my website, though it's probably below the level of everyone who has commented on this thread.
|
|
www.Auto-tat.co.uk'96 Range Rover P38 DSE (daily driver) '71 Reliant Scimitar SE5 GTE 3.0ltr Jag V6 Conversion '79 Reliant Scimitar SE6A 3.0ltr 24valve Omega Conversion '85 Escort Cabrio 2.0 Zetec - Sold '91 BMW 525i - Sold '82 Cortina 2.9i Ghia Cosworth - Sold '72 VW Campervan - Sold '65 LandRover 88" - Sold
|
|
melle
South West
It'll come out in the wash.
Posts: 1,998
|
|
Mar 25, 2015 21:11:13 GMT
|
I'm sure nobody will find a clear guide like that to be below their level!
|
|
www.saabv4.com'70 Saab 96 V4 "The Devil's Own V4" '77 Saab 95 V4 van conversion project '88 Saab 900i 8V
|
|
Smiler
Posted a lot
I no longer own anything FWD! Or with less than 6 cylinders, or 2.5ltrs! :)
Posts: 2,492
|
|
Mar 26, 2015 11:08:24 GMT
|
Ta very much It is the most popular part of the website.
|
|
www.Auto-tat.co.uk'96 Range Rover P38 DSE (daily driver) '71 Reliant Scimitar SE5 GTE 3.0ltr Jag V6 Conversion '79 Reliant Scimitar SE6A 3.0ltr 24valve Omega Conversion '85 Escort Cabrio 2.0 Zetec - Sold '91 BMW 525i - Sold '82 Cortina 2.9i Ghia Cosworth - Sold '72 VW Campervan - Sold '65 LandRover 88" - Sold
|
|
|
|
Mar 26, 2015 15:28:37 GMT
|
Ooooh...
/clicky
*n
|
|
Top grammar tips! Bought = purchased. Brought = relocated Lose = misplace/opposite of win. Loose = your mum
|
|