sequential fuel injection

sequential fuel injection

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darren no 7

Original Poster:

558 posts

247 months

Monday 2nd May 2011
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has any one tried fitting this to a ajp ,i am getting the 4.7 built for the race sag but want it to use the min amount of fuel poss as i want it to be as light as it can be in race trim,i have been told that the standard fuel injection fires fuel to two injectors at the same time when the sequential system only fires the one injector so uses less fuel,i have also been told it will give more power what do you all think any one tried it or will i be the first

FarmyardPants

4,099 posts

217 months

Monday 2nd May 2011
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Not an expert by any means but can't see why it wouldn't work if you use an ECU that supports it (and the AJP's vee angle of course). Not sure how much fuel you'd save since the unneeded fuel just sits in the inlet until the inlet valve opens, does it not? Maybe gain a bit of efficiency.

Alan Kee

136 posts

170 months

Monday 2nd May 2011
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You can get slightly better economy and emissions at part throttle/idle but don't expect anything better at large throttle openings. You still have to fuel safely for racing, and unless you run mahooosive injectors you'll never get an injector pulse short enough to fire all the fuel in when the inlet valve is open at high loads/rpm. So .. you set the injector end point for when the inlet is closing, but youve got to start the pulse waaay before the inlet opens to get enough time to fuel it at high loads/rpms .. you still get fuel standing around in the port even on sequential.

Even if you did have a big enough injector you'd have such poor resolution in the map at low rpm that you'd lose some of the control you need for good economy there anyway.
best bet is to forget about sequential unless you are running it with two sets of injectors where you can stage them for the best of both worlds.
In reality, how much % gain in power and economy are you expecting to get?

darren no 7

Original Poster:

558 posts

247 months

Tuesday 3rd May 2011
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in race form the 4.7ajp uses around 1.3ltrs per min,the race ls2 which is a 6.9 only uses around 1 to1.1 ltrs per min so i am trying to get it down to that or better.power wise 20 bhp would be good but only a guess. i am trying to keep the car with a tvr engine

fatjon

2,144 posts

212 months

Tuesday 3rd May 2011
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Assuming a brake specific fuel consumption figure of 0.5 which is quite typical for a racing petrol engine a fuel usage of 1.3 litres/minute equates to an output of roughly 200BHP. Which is probably about right as you are not on the throttle and maximum RPM for 100% of the lap. I don't think sequential injection will have any bearing on this at all. It is a method of controlling emissions at low RPM and once you get above maybe 3000 RPM the injection time exceeds the available valve opening window anyway. It looks like either to the bigger engined car is mapped better or he's just faster through the corners.

450Nick

4,027 posts

211 months

Tuesday 3rd May 2011
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darren no 7 said:
in race form the 4.7ajp uses around 1.3ltrs per min,the race ls2 which is a 6.9 only uses around 1 to1.1 ltrs per min so i am trying to get it down to that or better.power wise 20 bhp would be good but only a guess. i am trying to keep the car with a tvr engine
But the AJP will be making more power than the LS2 won't it?

I looked into running my 4.7 on sequential injection but was advised against it for a couple of reasons. Firstly you'd need to put in a cam sensor, which is a pain in the arse on an AJP due to lack of room. Secondly, I was advised that with a race engine, you really won't notice much difference in economy due to the throttle being wide open all of the time. A final point is that in a race engine, you can pick up some cooling benefit, as the extra spray of fuel in the cycle can help cool the cylinders slightly and ensure that there is a little extra charge in the runners.

You should speak to Ryan at SYVECS about this, he seemed very knowledgable on this subject and has run his own Tuscan road car on full seq injection, though has convinced me to go wasted spark on my race engine, albeit with more injector drivers than the MBE uses to reduce injector load slightly.

darren no 7

Original Poster:

558 posts

247 months

Tuesday 3rd May 2011
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same car and driver mapped at tvr power

Mr Cerbera

5,031 posts

229 months

Wednesday 4th May 2011
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450Nick said:
But the AJP will be making more power than the LS2 won't it?

I looked into running my 4.7 on sequential injection but was advised against it for a couple of reasons. Firstly you'd need to put in a cam sensor, which is a pain in the arse on an AJP due to lack of room. Secondly, I was advised that with a race engine, you really won't notice much difference in economy due to the throttle being wide open all of the time. A final point is that in a race engine, you can pick up some cooling benefit, as the extra spray of fuel in the cycle can help cool the cylinders slightly and ensure that there is a little extra charge in the runners.

You should speak to Ryan at SYVECS about this, he seemed very knowledgable on this subject and has run his own Tuscan road car on full seq injection, though has convinced me to go wasted spark on my race engine, albeit with more injector drivers than the MBE uses to reduce injector load slightly.
Sorry this subject is verrry interesting - but I know nothing !
However I would love to learn more sooo I ask....

1) What is wasted spark ?
2) What does more injector drivers mean in the physical world ?

Many thanks for any time you can spare on these explanations thumbup

Paul J.

nrick

1,866 posts

162 months

Wednesday 4th May 2011
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Hi Paul

Wasted spark is where the coil fires (in pairs normally) multiple cylinders at the same time. One will be on the ignition cycle i.e. full of fuel and air, the other on the exhaust cycle. There is no bang on the exhaust (well there shouldn't be) so the spark is 'wasted' i.e. not useful but still occurs. It makes the ignition system simpler and the cheaper than having individual coils but not as controllable.

nrick

1,866 posts

162 months

Wednesday 4th May 2011
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Multiple injector drivers are along the same lines. You can fire all the injectors at the same time which is the simplest system but the least efficient from a fuel point of view or you can have multiple drivers (the control hardware that fires the injector, a bit like a relay). The more drivers the more tunable the fuel injection is. Rather than run very big injectors you could run 2 banks of smaller ones, in different places. TVR did this in the GT cars I believe, it just gives you more chance to play with maps and fuelling for part throttle, idle, and wide open. Downside it adds more cost. The drivers get their signal from the ECU, so multiple drivers normally need a better ecu which is usually more expensive. Everything is a compromise.

SporttiJanne

112 posts

150 months

Sunday 4th December 2016
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Digging up this old topic: I tried to search, but could not find, where the cam position sensor is fitted in the AJP engines that have been converted to run injectors/coils sequentially? Has anyone done this yet?

Mr Cerbera

5,031 posts

229 months

Sunday 4th December 2016
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SporttiJanne said:
Digging up this old topic: I tried to search, but could not find, where the cam position sensor is fitted in the AJP engines that have been converted to run injectors/coils sequentially? Has anyone done this yet?
I think this was done by Jay at Powers Performance on MBE's new ECU.
There was an article in Sprint (14/15).


350Matt

3,733 posts

278 months

Monday 5th December 2016
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did it work?

Mr Cerbera

5,031 posts

229 months

Tuesday 6th December 2016
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350Matt said:
did it work?
The owner, Dave Parkes, was very impressed with it.


ukkid35

6,138 posts

172 months

Tuesday 6th December 2016
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SporttiJanne said:
where the cam position sensor is fitted ... ?
Good question - intrigued.

SporttiJanne

112 posts

150 months

Tuesday 6th December 2016
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Mr Cerbera said:
I think this was done by Jay at Powers Performance on MBE's new ECU.
There was an article in Sprint (14/15).
Would you be kind, and have a look at the article, and let me know, if there is a hint of the cam sensor placement? Unfortunately I do not have access to that article.
Or, if anyone else could share the information...

ukkid35

6,138 posts

172 months

Tuesday 6th December 2016
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Perhaps it uses the crank sensor making it wasted spark and wasted squirt!

Alternatively perhaps it's neither wasted spark nor wasted squirt, and it alternates between the two until the engine fires and then sticks to that.

I'm joking of course, how do other timing chain engines fit cam sensors?

jamieduff1981

8,022 posts

139 months

Tuesday 6th December 2016
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Jaguar AJ-V6 (related to Ford Duratec V6)



The camshaft sensors are the dark cylinders located above and between the camshaft sprockets. The big aluminium cylinders on the end of the inlet camshafts (inner pair) are variable valve timing units though.

gruffalo

7,509 posts

225 months

Tuesday 6th December 2016
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ukkid35 said:
SporttiJanne said:
where the cam position sensor is fitted ... ?
Good question - intrigued.
With no VVT on these engines is a cam timing sensor needed or could you take a feed off the crank sensor and extrapolate a cam position from that?


ukkid35

6,138 posts

172 months

Wednesday 7th December 2016
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gruffalo said:
With no VVT on these engines is a cam timing sensor needed or could you take a feed off the crank sensor and extrapolate a cam position from that?
That was my point, perhaps it could guess which stroke it's on (compression or exhaust) and just use the crank sensor when it's got the answer right.