Hard data on effects of injector position on engine power

Following various earlier discussions, does anyone have any hard data on the effect of injector siting on engine power/torque characteristics?

What I mean by this is that the perceived wisdom is that injectors close to the head/valve are good for emissions and throttle response, and injectors further away from the valve are better for top end power.

If you look at race motors, many of them have injectors far away from the head, often outside the bellmouths even

But how much difference does it make ACTUALLY? Is it 10hp, or 1hp.......

I have never actually seen any hard data to suggest how large this effect might be.

I know from engines of a smilar spec to mine that on an engine dyno, moving from DTH 45's (with a close injector) to DCOE 48's (with a mid distance placed injector) gives 15/16hp, something in that region. But of course this could be just due to the larger throttle body size.

I have just ordered some DTH 48's from Bill and will run some tests soon, but I will also be trying a different injector type which could also affect the results unfortunately.

So what data do we have?

Cheers

Rob

 

http://www.hotrod.com/pitstop/hrdp_0704_pitstop_fuel_injector_location/index.html

some interesting info there

on a 1000hp engine, 50hp (5%) gain on moving the injector from 7" to 14" from the head - but it wouldn't idle below 1600rpm

[i.e possible 10hp on a 200hp engine]

large injectors have to be distant from the engine to allow time for fuel atomisation (by large, meant 96lb/hr....which are HUGE and at least double what anyone would ever use on a valver running petrol)

seems like the issue is better atomisation with a distant injector - but with modern injectors with multi-pintle spray patterns, atomisation is much more uniform than the old days anyhow.....so maybe as time goes by, the benefit of distant injectors will diminish...?.dunno

thinking about cars like berg cup cars - as these rev so high (12K rpm+) - presumably thats why they need distant injectors to give the fuel a bit more time to mix with the air on each stroke - again, not really needed perhaps on a 7-8K rpm engine?

 

Hard facts Rob, I've seen none.

Decent sources of information seem to suggest around 5% - so a potential 10 BHP on a 200BHP engine, which would seem reasonable, if mapped accordingly.

I've not got mine fittted yet to go playing.

 

I'm too slow again...

I'm fairly confident gains can be found...but probably at the expense of emissions at idle.
Maybe 8 injectors is the answer to that.

 

I dont really doubt there will be some gain - what I am wondering is how much

conclusive data seems very sparse

 

Rob are you going for RC Injectors

 

nope



Bosch EV6 'green giants' as used on volvo turbo's - P/N 0 280 155 968 - 14-ohm modern duel cone injector to replace the Cossie garden hoses that I have been using previously

Calc:

280hp needs 322cc petrol/min (100% duty cycle) or 402cc/min (80% duty cycle)
these flow 440cc at 3bar, 465cc at 3.8 bar, and I will probably run them at 4 bar so there is plenty of capacity in them (even just about for some alcohol work.......)

exciting

anyhow - back to topic......

 

Are 1.8T EV6s too small?
I'd have thought TT/S3 225 injectors would have been good too - they'll flow enough for 280BHP @ 3 bar, and are easily found for peanuts.

 

whats the p/n on those injectors?

 

Hmm...I'll have to dig it out.

 

I'm using two sets of 180 1.8T EV6s:
317cc @ 3 bar
VAG No: 06A 906 031 BA
Bosch No: 0 280 156 061

It looks like 225 AMK/BAM injectors are the longer EV12s. Any use?
386cc @ 3 bar
VAG No: 06A 906 031 BC
Bosch No: 0 280 156 064

I can't say I can remember my S3 injectors being EV12 type, so can't be certain...I thought they were the shorter EV6 type as shown above. May be wrong though. They certainly flowed enough for 280 BHP but it was getting marginal on duty cycle, at 3 bar.

 

My current ECU will only support 4 injectors, and I want to try ethanol at some point soon, so I needed something with more flow than 1.8T injectors (even the BAMs)

also, a friend of mine who builds some awesome duratec engines (2L, >300hp) recommended these

I was contemplating some 550 genesis injectors (as recomended by USRT - excellent website if you have a few mins spare to browse) but settled on these for now to try and get as fine and uniform a spray pattern as I can

They can be bought from the US for <200 USD a set

USRT - http://www.usrallyteam.com/index.php?main_page=index&cPath=10_44

 

225PS injectors are EV6 at 61mm long same as 180PS.

That Volvo injector is a 443cc job @300kPa supply 12Ohm impedance. The length is 73mm.

 

They are good at shipping too!
A mate bought some lightweight lifters from them for my old VR6 engine. Great service.

It'll be interesting to hear how you get on.

 

That's why I don't remember them being the longer EV12 type length, then?

The spreadsheet I was looking at has them incorrectly listed as EV12s.

 

right lads - back to the thread topic.....

hard evidence of power trends via injector position.....

 

The spread is incorrect with the part number your qouted above as a EV12 unit. There are EV12 varients found on the 225PS spec engine.
0280 155 892/3 are EV12 12 Ohm injectors VAG# 06A 906 031 J 386cc/min on 300kPa Heptan supply.

 

Regarding injector position, I would have thought we started to touch this subject in the 8 injector thread some time ago.
With fuel injection it is all about improving the homogeneous mix prior to entering the combustion area. This mix will be affected by the type of cylinder head 2V or 4 or 5v, injector spray pattern, manifold/port shape and airflow. A production engine has to pass emission regulations that became stricter as the years have gone by and has a limited range of RPM that does not justify a cost increase of adding extra injectors for high rpm/airflow. Even the JDM Honda engines that in production spin up to 8500rpm, B16A 170PS for example, have suitably sized disc injectors close to the inlet valve and passed JDM emission stds at the time. I would think that on an maximum effort engine, where every little helps, development costs, emissions, fuel economy and goverment limits are not an issue, placing the injectors, at higher pressure are an optimum distance, tuned to mix with airflow at higher engine speed where trapping efficiency ( on cam) is best, may justify the imminent wall wetting that will happen at slower air speeds as the fuel droplets dropout of the air mix.
Or as said have 8 injectors staged to minimise these effects.
The fuel supply pressure and the injector distance from the valve will have to be played with in order to determine what is best for you. If running 8 squirters then the switch on time and hysthesis as one set ramps in and out will also have to calibrated for smoothness.
That is my 2pence on this.

Scott@USRT is the man I spoke to when I bought my 630cc hose pipes. Very helpful he was on walking me through what I wanted for my multivalve boosted engine. I did have some idea what was required though which helped.

 

Yes we touched on it in that thread - but we still dont have any data, only theory and old wives tales.

My interest is focussed on how much a difference distant injectors make.

I have my own personal theories for engines that we deal with (and not F1 / WRC / touring car or whatever engines).

Until we have some reliable data, mindless comments rubbishing solutions that are working well will continue.

And that needs to be nipped in the bud.

 

Mindless comments and old wives tales will continue even with data as people still swear sidedrafts are better than EFI and so on.
The best bet would be to test your theories and possibly what I touched on, scientifically, on a target engine then share with the mindful ones on here if you choose.