Need bigger injectors..??

kokkolanpoika · Post by **kokkolanpoika** » Thu Jun 21, 2007 8:33 pm

Hi..

I just notice that my std Rover v8 3,9 efi injectors are too small for my stage3 4,6.. ( at least 280hp 3-years go, but hope litle bit more now +300hp i estimate??)
They are 100% open over ~4000rpm to 6000rpm?
Also fuel pressure is ingrased to 3,3bar.. But need more fuel, because car pluck litle bit over 5000rpm, and air/fuel gauge shows also light lean mixture @ full throttle.. (all ignition parts are good contidition)
I also try to get lean the mixture (duty cycle 85%), but car pluck very badly then.. Run mutch mutch better with 100% duty cycle.

I just wonder is those injectors suitable for my 3,9 fuel rail/manifold??

Accel is cheaper..
http://store.summitracing.com/partdetai ... toview=sku
Accel O-ring seals are slightly bigger that Ford Racing??
Rover O-ring seals are 99% same size as Accel

ford racing..
http://store.summitracing.com/partdetai ... toview=sku

Has anyone experience those injectors??

ian.stewart · Post by **ian.stewart** » Thu Jun 21, 2007 8:40 pm

The only problem with fitting bigger injectors , especially too big, will be poor atomisation,

kiwicar · Post by **kiwicar** » Fri Jun 22, 2007 8:08 am

those injectors seem a bit large, 300bhp should be about 22 lb/hr, with 30lb/hr should take you to 400 bhp as Ian says the fueling at idle could be difficult to get get steady with the bigger injectors. What UCU are you using?
Mike

kokkolanpoika · Post by **kokkolanpoika** » Fri Jun 22, 2007 8:37 am

I need bigger injectors in near future, because i also build 5,3 or 5,5 stage 4 engine.. And that need fuel..

I dont want to buy 2 times unnecessary injectors..
I run with Haltech programmable ECU.
If i cant make this 5,3+++ engine, still i but my stage 4 heads 4,6 bottom end, and hope to get 330hp..
I still need bigger than 22lb/hr..??? if i get over 330hp..

kiwicar · Post by **kiwicar** » Fri Jun 22, 2007 9:47 am

Rather than spending the money on a 5.3litre+ engine, would you not get more power by keeping with the 4.6 engine and going to a set of the real steel E85 heads? as the 4,6 heads even ported as far as they go are ultimatly the power limiting factor? certainly be cheeper and less fragile.
Or is it going in a tractor?
Mike

kokkolanpoika · Post by **kokkolanpoika** » Fri Jun 22, 2007 10:20 am

kiwicar wrote:Rather than spending the money on a 5.3litre+ engine, would you not get more power by keeping with the 4.6 engine and going to a set of the real steel E85 heads? as the 4,6 heads even ported as far as they go are ultimatly the power limiting factor? certainly be cheeper and less fragile.
Or is it going in a tractor?
Mike

Yeah Tractor..

Its sd1..
i think i can get more power (homeported) stage 4 5,3 vs 4,6 + Real steel E85 heads..
I want to see 4,6 power curve with those E85 heads.. Speech are hard that those heads flow good, but ever saw a truth/dyno sheet..

I spend my money to 5,3+++ + E85 heads..

Or ewen wildcat..

kiwicar · Post by **kiwicar** » Fri Jun 22, 2007 12:47 pm

Now a 5,3 and wildcat heads would be fun !
Mike

kokkolanpoika · Post by **kokkolanpoika** » Fri Jun 22, 2007 12:51 pm

Back to the original question.. I just want to know is those both injectors suitable my std fuel rail/inlet manifold??
Without any comment of their size..

kiwicar · Post by **kiwicar** » Fri Jun 22, 2007 2:10 pm

Don't understand what you mean by "99% same size" (same size but to different decimal places, one imperial size the other the closest metric equivilant) it is either the same size or it is not surly???

You have the measurments off the website (which seem reasonably complete) and 8 injectors in the car to measure. If the top and bottom diamiters are the same as the rover ones then they should be a snap in replacment, if not you will have to bore them out the right size. same goes for the fuel rail. The height of the injector should not be that critical as all that will dictate is how high the fuel rail sits and provided it doesn't hit anything as a result...
Mike

kokkolanpoika · Post by **kokkolanpoika** » Fri Jun 22, 2007 4:31 pm

I mean that rover original 'O' ring seal are almoust same size as accel type..
Slightly different size.. some tenth millimeters if measure at vernier caliber..?
And i also want to hear that height of the injector should not be that critical.....
I just look at there is enought room to fit "longer" injectors..

kiwicar · Post by **kiwicar** » Fri Jun 22, 2007 8:19 pm

if the accel ones are 10ths bigger it is probably that they are not squashed by being pushed into the hole and sealing the injectors in place. As I said in my last post if they don't hit anything as a result of being taller then the height will not be critical.
Mike

stevieturbo · Post by **stevieturbo** » Fri Jun 22, 2007 11:12 pm

ian.stewart wrote:The only problem with fitting bigger injectors , especially too big, will be poor atomisation,

Ive run 1000cc injectors on a 2.2 4 cylinder.

Buy decent injectors, and it wont be a problem.

Im using 73lb/750cc on mine, at 4.25 bar, and they also work fine.

The poor atmosiation thing is old tech, unless the injectors or ecu really is crap.

If you are using hotwire stuff, just buy a set of the Ford SVO green 42lbs

They worked perfectly in my RV8.

Or a set of Siemens/Mototron 60lb ( small black inj ) are excellent items, and will cope with big power.