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melle
V4 Guru

United Kingdom
3342 Posts

Posted - 14 May 2020 :  21:50:10 Show Profile Reply with Quote
I found some formulas for injector sizing here: https://www.rcfuelinjection.com/Technical (they're also in the book I linked). I've made my own calculator in Excel based on the formulas so I could play around with the data of the injectors I have, in units I understand.

I reckon I can get about 90HP out of a high compression 1.7 V4 without spending money on a "hot" cam and other trick parts.

  • Number of cylinders 4
  • BSFC (Brake-Specific Fuel Consumption) 0.5
  • HP 90
  • Duty cycle 80%
  • Injector cc/min 148


The 2.9 injectors flow 147cc/min at the prescribed 2.7 bar fuel pressure and a safe duty cycle of 80%, so that should be close enough. If not, I could try a set of Fiesta/ Escort ones I also have, which do just under 200cc/min at the same pressure.

www.saabv4.com
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Borstlap
V4 Fanatic

Norway
301 Posts

Posted - 15 May 2020 :  12:08:12 Show Profile Reply with Quote
Hi Melle,
Yes that is the sensor I am using. It is a while ago I looked at the XP trigger wheel and their site didn't work well on Android so I couln't open it yesterday. The bit of a challenge with using the flywheel I meant is determining where the right place of the trigger pattern getting it done physically and of course having the flywheel balanced again. I saw that the guy with the Jenveys used the inspection hole in the Bell housing as the point of entry for the sensor.

Alex
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Borstlap
V4 Fanatic

Norway
301 Posts

Posted - 15 May 2020 :  14:51:24 Show Profile Reply with Quote
Managed to take a look at the XP trigger wheel. You're right, they state it is meant for use with a non standard flywheel. Melle, what are your thoughts about pressurizing fuel, high pressure from a pump near the tank and a return line or a swirl pot with high pressure pump in the engine compartment?

Alex
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melle
V4 Guru

United Kingdom
3342 Posts

Posted - 15 May 2020 :  15:14:37 Show Profile Reply with Quote
Trigger wheel positioning isn't critical with Speeduino, as far as I know you can compensate in the software for the trigger pattern being (way) off. I don't think you can in Megajolt/ squirt? Or only a few degrees?

My idea was to do this




Or this:




I don't think balancing will be all too difficult. If I turn a short axle and use two pillow bearings, clock it level and statically balance it, I think it will be acceptable for a road engine. Or just drop it off at a machine shop...

Regarding fuel: I haven't really looked into it yet to be honest. I was hoping to keep the low pressure pump under the rear seat, and add a high pressure Walbro (clone) and a fuel pressure regulator in the engine bay and a return line T-d into the supply line before the low pressure pump close to the tank. Not sure if this will work, or if I may need a swirl pot. Ideas welcome!

www.saabv4.com
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Borstlap
V4 Fanatic

Norway
301 Posts

Posted - 16 May 2020 :  20:47:15 Show Profile Reply with Quote
You're correct, with Megajolt there are only a few degrees that can be compensated for, by heart 10 degrees to the next tooth of the trigger wheel. Has to do with the Edis module where the signals come in and go out.

I took a quick look at the flywheel of the spare engine in the garage and the concept with the holes should work, there's enough metal on the outer edge beyond the circomfence of the pressure plate boltholes.

Alex
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Dirtbiker
V4 Mad

United Kingdom
867 Posts

Posted - 16 May 2020 :  22:26:09 Show Profile Reply with Quote
Melle - I have had a quick look at ebay Porsche 944 throttle bodies. Do you know if the bolt pattern is the same as the 2bbl manifold or does an adapter need to be made?

I might take a 2bbl manifold to an engineering place I am friendly with in Plymouth this week and see if they can modify as per the photo you posted to accept individual injectors.

Cheers
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melle
V4 Guru

United Kingdom
3342 Posts

Posted - 17 May 2020 :  19:25:27 Show Profile Reply with Quote
This (slightly wordy) post is about my K-Jet V4 project; Dirtbiker I hope it answers your questions too! Let me know how you get on with a quote from your local machine shop, I may be interested in having a manifold done as well if they offer a discount for multiples.


Somewhere around 2014 or 2015 I started working on a V4 Bosch K-Jetronic injection conversion, basically for no other reason than wanting to do so. I'd heard of people converting V4s to K-Jet before, but I'd never seen a conversion in the flesh. These forum threads were what got me going: http://www.saab-v4.co.uk/speedball/topic.asp?topic_id=393&whichpage=1 and http://www.saab-v4.co.uk/speedball/topic.asp?TOPIC_ID=3246 As you can read in the latter, David "blue95V4" sent me scans of two SEC magazine articles in which a Danish chap explained how he converted his Sonett to K-Jet. His articles were very helpful and he emailed me some further information as well.

K-Jetronic (continuous mechanically controlled injection) is great because parts are cheap, easy to come by and I have a bit of experience with the system from my '88 900. I love its ingenuity; K-Jet has a reputation for being "difficult", but the design is very nifty and I've never had issues with it in the nearly 9 years I've had my 900. A great advantage of K-Jet is that it's been used on many different cars from many different manufacturers like Saab, Volvo, Porsche, Ferrari, BMW and Mercedes. All car makers that seem to know what they're doing. Many parts are, or seem to be, interchangeable, but it's very hard to get specifications from Bosch. Trial and error is a tried and tested method here though, so I'm sure I can build something that will work.

K-Jet can be upgraded to KE-Jetronic, in which the "E" denotes "electronic" and indicates a few extra bits, like a lambda sensor and ECU (electronic control unit), are added to the mix. This way the system is slightly more advanced in how it controls the air-fuel ratio, and hence a little more powerful and fuel efficient. With power to the ECU switched off the system runs as K-Jet again, which is handy in case the ECU fails. Lastly, there is the option of adding a turbo. Hmmm, interesting! But too many other projects for now...

The plan is to use a mix of K-Jet parts from different cars. I've collected a myriad of parts from Saab 900, VW Golf GTI, Audi 80, Porsche 944 and Ford V6 over the years, just to see what might fit. I had some K and KE-Jet spares for my 900 already, and I got some more from two friends. Inspired by the Danish chap's articles, I set off drawing up a design for a 90-degree adapter between the 2bbl V4 inlet manifold and a Saab 900 throttle body, of which I had a plain K-Jet version and a KE-Jet version with a throttle position sensor. The adapter needed the 90-degree angle, or the throttle body would sit too high for the bonnet to close. I had some flanges water jet cut and that is as far as I got. Only because a better alternative was looming! One of my many K-Jet googling sessions led me to the K-Jet variant used on Volvo 200-series. Where the 900-throttle body is incredibly bulky, the Volvo version used on BE21 engines is nice and compact, which allows for mounting without the 90-degree adapter. I would only need to draw up a simple adapter plate, and have it water jet cut or CNC-milled. I went to a Volvo breaker and he had one, but wanted silly money for it, so the search for a BE21 throttle body went on. (For some reason I thought at that point only a TB from a K-Jet engine would work.)

I had earlier used Volvo 240 parts to convert a V4 distributor to a Hall system, but I used VW Golf and Scirocco parts for that a couple of times as well. This got me thinking: the MKII Golf had 1.6 or 1.8 engines and a least some of them were fitted with K-Jet. Their displacement is much closer to that of the Saab 1.5 or 1.7s than the two-litre 900 engine. Maybe a Golf K-Jet system would be a better match for the V4? The hunt for Golf parts was on. I found that not only had the Golf a two-choke throttle body, which I hoped might improve low rpm driveability, but more importantly it looked like it would fit a V4 2bbl inlet manifold. The only way to find out was to buy one. So I did. And it did. Like a glove. The throttle body slides right over the four carb studs; not sure if there is a DIN specification for carbs and throttle bodies? Great, this not only means a relatively straightforward adapter to the inlet manifold, it also means an even more compact design than the Volvo TB and hopefully better performance because of the 2-barrel design. I now have a few different VAG four stud TBs and a mix of Audi and VW rubber ducting to go between the fuel distributor and the TB.


Saab 900 and VAG throttle bodies (I've collected a few more over the years, but I don't have pics of them).




Confirmation of my hunch the Golf TB might fit the 2bbl V4 manifold.




I need a spacer between the TB and the inlet, because the injector bosses will interfere with the throttle linkage if the TB would sit directly on the manifold. I started with paper prototypes to figure out how much space I would have for an adapter that also incorporates a take off for the brake servo, a PCV valve and a cold start injector.




Then I made a slightly more accurate wooden prototype.




And finally, I drew up adapters for a Golf and a Porsche TB in CAD. I'm not sure which one to use yet; they need different adapters because of a few design differences. I rarely rev my engines over 4000rpm and I want peak torque in the 2500-3000 band, so I think a smaller primary butterfly may be the best choice. I'll have them 3D printed for a final fit, and then I'll have my mate water jet cut the basic shape and I'll do the rest by hand, or I'll leave all the work to a wizard with a CNC mill, not sure yet.




What slightly worries me, is the lack of intake volume/ runner length, which would be less of an issue with a 90-degree adapter that would act as a plenum and add some extra volume, or with a high revving engine. Not sure how much of a problem this will be in practice; there are bolt on injection conversion kits for other carburettor engines that seem to work fine. The intake ducting between the air filter and the TB will be pretty long, hope that may reduce the issue? I'll do some more research and calculations when I have time.

There will be a solid aluminium block with coolant channels plumbed into the cooling system (fed with the lines that normally serve the auto choke) for the thermo-time switch, the auxiliary air valve (AAV) and the warm up regulator (WUR).


In the meantime I've built an engine test bench. It's a fair bit more finished than it was when I took this photo and now has a dashboard too, but I can't find a more recent pic.




The plan is to first get an engine running on K-Jet on the test bench, and if that works install it in a car. The exhaust on the test bench is already equipped with a bung for a lambda sensor, so an upgrade to KE-Jet, or even turbo, is an option. Let's see where I get with the basics first when I get back to the workshop and do some actual work on this project. At some point...


www.saabv4.com

Edited by - melle on 17 May 2020 19:33:58
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melle
V4 Guru

United Kingdom
3342 Posts

Posted - 18 May 2020 :  12:59:29 Show Profile Reply with Quote
Here's another cool V4 EFI project: https://www.norotors.com/index.php?topic=23366.0

www.saabv4.com
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AnttiK
V4 Beginner

Finland
64 Posts

Posted - 18 May 2020 :  17:05:19 Show Profile Reply with Quote
Hello from Finland!

I have 96 V4 -73, which my father bought when it was new. It was used almost daily until 2002 and was taken again in to use as our a wedding car in 2007. In 2010 I decided to install EFI to the car, because it was and it is so interesting to see the evolution of the old car. But first I had to do almost complete overhaul to the car. A lot of welding, grinding, painting etc.

In the beginning of summer 2019 I was finally able to drive the car with Megasquirt 1 installed with following features:
-Peugeot 206 1.4 engine throttle body with ~39mm diameter installed to 1 barrel intake manifold
-Peugeot 306 1.6 fuel injectors 156cc
-Volvo740/Saab900 fuel filter
-Ford EDIS4 controller and edis coil pack
-QSP fuel pump in tank with 3/8" feed and return lines
-36-1 trigger wheel installed to balance axle pulley
-Volvo740 2 wire bosch idle pwm valve (same as in Saab9000?)

Here is a picture of the throttle body and fuel rails:


And engine bay:


It was fun to drive the car last summer. Better throttle response, better startup, less fuel consumption, milder exhaust fumes and so on..

In the end of last year I decided to fit 7.2 cam, sport exhaust from swedish saabclub modified with larger mufflers and Megasquirt 2 for more precise engine control and sequential injection. And the car works even better than last summer. Exhaust produces less noise inside the car, more power and less fuel consumption.

In the future I have plans to install 1.7 crankshaft and ohc pistons for more power and better economy with higher compression (which I already have in my garage). Intake manifold modification to plenum type and dual port exhaust by using divider plate in exhaust.

Edited by - AnttiK on 18 May 2020 17:07:13
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AnttiK
V4 Beginner

Finland
64 Posts

Posted - 18 May 2020 :  18:20:47 Show Profile Reply with Quote
My solution of the trigger wheel sensor installation bracket is made of L-shaped steel. Sensor distance from trigger wheel can be easily adjusted by using shims and alternator belt can be removed without touching the sensor. Of course modified flywheel with trigger pattern would be more sophisticated solution. May be I'll do that in the future.

Edited by - AnttiK on 18 May 2020 18:22:12
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melle
V4 Guru

United Kingdom
3342 Posts

Posted - 18 May 2020 :  22:40:05 Show Profile Reply with Quote
Welcome aboard and thanks for posting! Nice back story, great conversion and even better plans. I was thinking along the same lines for the sensor bracket. Did you use standard extruded fuel rail profiles and AN fittings? Can you tell us more about your fuel set-up, did you modify the existing tank, or build a new one? What did you do with the oil pump drive shaft?

www.saabv4.com
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Dirtbiker
V4 Mad

United Kingdom
867 Posts

Posted - 18 May 2020 :  23:00:30 Show Profile Reply with Quote
Melle - great post on the K-jet, very interesting! I'll hopefully speak to my guy this week about modifying manifolds.

Anttik - be great to see a thread on your 96 - my 96 was bought new by my father in 1972!

Cheers
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AnttiK
V4 Beginner

Finland
64 Posts

Posted - 19 May 2020 :  04:53:12 Show Profile Reply with Quote
Thanks Melle and Dirtbiker!

I used standard fuel rail profiles, which were CNC machined by AMW Dyno service in Finland. I used AN6 fittings and route of the fuel lines is the same as with standard fuel line. Total cost of the AN6 parts was quite high, but they look nice and are reliable, which is important.

I made aluminium flange with CNC to fuel tank for fuel pump installation and connections of the fuel lines outside the tank are close to the standard placement.


For oil pump axle drive with MS1 I just cut the top end of the distributor smaller. For MS2 with sequential injection I modified the distributor for cam sensor using ford VR sensor, which I do not have picture of it right now. Another solution for cam sensor could be US 4.0 V6 cologne cam sensor, but I am not sure if it fits.

Edited by - AnttiK on 19 May 2020 04:56:32
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Derek
V4 Guru

United Kingdom
2019 Posts

Posted - 19 May 2020 :  11:09:18 Show Profile Reply with Quote
Do you have a picture of your modified inlet manifold? It looks like a bit of skilled welding went on there.
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AnttiK
V4 Beginner

Finland
64 Posts

Posted - 19 May 2020 :  12:39:04 Show Profile Reply with Quote
Yes i have. Local welding workshop welded the injector buns with TIG. Injector buns were self made with lathe.



After that I exchanged my MIG welding machine to one, which can be used for aluminium welding and made approx 70mm high adapter (plate -tube - plate) between manifold and throttle body. And I can say that welding aluminium with mig is quite difficult. I tested the air seal of the adapter many times under the water with pressurized air and made correction welding to it. Adapter is so ugly, that it is good it is under the air filter But it works.
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