question for the guys running boost..

where is thier limit with say an aftermarket ecu and a raising rate FPR,

i don't really want to run an extra injector.. would preffer to run slightly larger injectors..

say stock 6G72 turbo injectors? or the 2.5 twin turbo galant injectors? only problem is getting a hold of them..

thinking about 6G74 with a single turbo running about 7psi boost..

And you think you 4spd auto will agree with you on this? :bowrofl: :bowrofl:

Itll quit and quit in a big way.

That, and the fact that you wont do it anyway.................sorry im just a negative person.

question for the guys running boost..

where is thier limit with say an aftermarket ecu and a raising rate FPR,

i don't really want to run an extra injector.. would preffer to run slightly larger injectors..

say stock 6G72 turbo injectors? or the 2.5 twin turbo galant injectors? only problem is getting a hold of them..

thinking about 6G74 with a single turbo running about 7psi boost..

I don't know what the limit of the factory injectors is, and I don't think anyone else would know either. I was going to leave injectors till last, and try and tune the car with the standard ones to see what they could handle, but mid way thru the project I decided I didn't want to waste any more time than I absolutely had to - and got some injectors sourced while other **** was going on.

From my research - I know that Cthulhu and JasonsVRX were both running factory 3.5L injectors on their NA beasties with 207 and 240 front wheel kW respectively. My factory injectors were sent to a fuel injection specialist and flow tested, and it was deemed that they wouldn't be up to the task and were subsequently upgraded.

I don't know what the limit of the factory injectors is, and I don't think anyone else would know either. I was going to leave injectors till last, and try and tune the car with the standard ones to see what they could handle, but mid way thru the project I decided I didn't want to waste any more time than I absolutely had to - and got some injectors sourced while other **** was going on.

From my research - I know that Cthulhu and JasonsVRX were both running factory 3.5L injectors on their NA beasties with 207 and 240 front wheel kW respectively. My factory injectors were sent to a fuel injection specialist and flow tested, and it was deemed that they wouldn't be up to the task and were subsequently upgraded.

I did run the stock 3.5 injectors (although i did fit a brand new set) for awhile but they were basically at full duty cycle and thus wernt going to handle that for a long amount of time, so i modded the fuel rail and fitted different injectors then redid the ECU map to suit.

When my dad changed his injectors in his XR6T to bigger units, we did a comparison of the stock turbo falcon injector (which is also the same injector used in the non turbo models) and the 3.5 magna injector and the falcon unit flowed only slightly more. This seems about right given that the stock falcon injectors are pretty close to maximum at around 240Rwkws.

I also run a hi volume walbro fuel pump and a 1.7:1 rising rate fuel reg on my magna.

And you think you 4spd auto will agree with you on this? :bowrofl: :bowrofl:

Itll quit and quit in a big way.

That, and the fact that you wont do it anyway.................sorry im just a negative person.


tell that to Jose and his twin turbo 400+ hp atw diamante

thats runing a 4spd auto!

and it goes pretty good to the tune of low 12's with mega wheelspin lol

slightly off the topic a little.. but what is actually the weak point of the auto? the converter? diff? gears? i'd most likley consider it manditory to do more frequient oil changes, auto fluid doesn't like being excessivley heated repeatedly (above it's range).. as with almost any oils..

Thanks black beard and jason, i may just see if i can get them flowed a bit.. run a decent fuel reg, see how the tune goes..

slightly off the topic a little.. but what is actually the weak point of the auto? the converter? diff? gears? i'd most likley consider it manditory to do more frequient oil changes, auto fluid doesn't like being excessivley heated repeatedly (above it's range).. as with almost any oils..

Thanks black beard and jason, i may just see if i can get them flowed a bit.. run a decent fuel reg, see how the tune goes..
I don't know that there is a real "weak point." mine's been running fine for almost 12 months with 225+kw and 400+nm.

like you said, fluid flush every now and then and it should be fine.

wrt the injectors, my stock ones have been up to the task so far... I might upgrade them later, but right now there's no need.

cheers,
.wook

If you up the fuel pressure you'll up the rate of the injectors, just incase you find they run out of puff

haha yeh i know, i've worked out that for approximatley every 10psi additional rail pressure you get approx 18-20cc worth of fuel.. but too much pressure starts turning the spray pattern to ****..

plan would be after i do all the fab work.. i'll just crank in the fuel pressure to limp it down to the tuner where a unichip will be fitted and tuned..

it shouldn't be too bad.. plan would be to use one of those slim coolers.. 2.5" in and out.. fit nicley in the lower bit of the stock bar

Overdo it (rail pressure) and they wont seal properly either! Was a problem on the turbo Saabs running 5 bar regs (and a $hitload of boost)

lol!!! 73psi rail pressure!! + boost?? jeeeebus!!

in my 300kw magna (as thought to be by other members, due to the kw figure atw) the injectors (stock 100,000km old) were at 90-95% i forget now but definatley had some more room left but only a tiny bit! only upgrade to the fuel system was a walbro intank pump...

the 7th injector was at about 60% no idea on the size and flow of that bugger though..


so unles you pushing more than 250kw at the fly minimum i wouldnt bother with injectors

i don't like the idea of running 1 extra injector.. it just doesn't seem like a proper way of doing it.. more like a bandaid approch..

i know it obviously works.. but i my previous engine builds there was many many options.. like in my AE86.. 4AGZE (superchanged 1.6) come with 365cc, need bigger? use 7MGTE ones 440cc.. and in my hi-comp quad throttle 4AGE, i used 7MGE 285cc injectors instead of the 220cc 4AGE ones.. 20v 4AGE u can use 365cc 1JZ, or 440cc 3SGTE..

thought there may be a cross over for some slightly larger injectors that drop in.. and require a different map, rather than running an extra injector in the plenum..

it had the 7th injector cos it needed it cam with the s/c kit

why not go carby, those were the days you could stop on the side of the road pop the bonnet turn a screw a lil bit and thunder off again, then stop hop out turn the dizzy a lil advancing the timing repeat till it went nuts! no computer geeks and dynos in site!

it had the 7th injector cos it needed it cam with the s/c kit

why not go carby, those were the days you could stop on the side of the road pop the bonnet turn a screw a lil bit and thunder off again, then stop hop out turn the dizzy a lil advancing the timing repeat till it went nuts! no computer geeks and dynos in site!

he is talking about a 6g74 engine, right? roflcopter

anyway, there are replacement high flow injectors... TZABOY and EGO have some, I'm sure.

been there and done that lol!! i had a G200 powered TG gemini.. bored out to 93mm, and offset ground crank to give her about 2400cc, used forged pistons from a toyota deisel of sorts (not sure as i bought it off a mate), twin 40mm webbers (kinda small), big cam, big 4-1's and a hand full of timing.. made 118rwhp and ran a 14.1 @ 98mph.. she used to boogie!! had white walls on her and everything.. but that was only about 3 years ago lol.. it was my daily before i bought my TH exec..

ok now thats getting waaaaaaaaay off topic..

lol!!! 73psi rail pressure!! + boost?? jeeeebus!!

Yairs. They didn't seal very well when you lifted off the throttle. At 25psi boost you had some very serious pressure. Used to leak around the banjo joints with stock plastic Saab washers - replaced with some copper washers got rid of that issue. Used to kill fuel pumps as well, they got pretty noisy.

As an aside, why has no-one considered adding 6 extra injectors? Simple enough to come up with a driver (so they are sequential) - ie. use the piggyback to to pulse extension/retardation a diode multiplexed injector signal (ie. mix all 6), and use the injector pulse to enable that injector. Easy. Jaycar pulse adjuster could do it (with some added electronics)

i think that using 6 larger injectors in the factory placement would be far eaiser than rigging that up, machining 6 extra injector bosses, and making 2 extra fuel rails, and running the extra lines..

doesn't it seem like it's the long way of doing it rather than simple dropping in some slightly larger injectors? either way it would need some sort of piggy back computer to control timing when on boost..

i know which one i'd preffer..