subaru fuel injectors

[gs14racer]

Do you guys know if subaru injectors will work in the 94+ vh rails. I would imagine they would, i know the subaru injectors work on sr20/ka24s, and i can get 8 750 or 850cc subaru injectors for about 550.

[CrazyTrance]

Well i dont remember where i heard/read this but... I thought i remember seeing somewhere that SR injectors are the same as the 94-96 VH injectors.. so like you said i dont see why they wouldn't work.

well idk after reading this thread... showthread.php?t=26696

I would say try and figure out the part numbers

[gs14racer]

thanks for the link, thats exactly what i was looking for..

According to the pics they subaru ones are exactly the same as the brown top jecs.

Now the question is 750 or 850, i think ill endup with the 750's, although my ka-t buddy whos pushing like 700 whp on e85 is trying to talk me into switching over.

I dont know if 750s will be big enough for e85 though, i may need at minimum 850s for e85.

[infamous_t]

Rule of thumb for e85 is size up fuel system 30% more than pump iirc.750cc should see 700whp on e85

[SuperHatch]

thanks for the link, thats exactly what i was looking for..

According to the pics they subaru ones are exactly the same as the brown top jecs.

Now the question is 750 or 850, i think ill endup with the 750's, although my ka-t buddy whos pushing like 700 whp on e85 is trying to talk me into switching over.

I dont know if 750s will be big enough for e85 though, i may need at minimum 850s for e85.

750cc injectors will flow enough fuel on a V8 for about 1000 crank horsepower on race gas. With E85, I'd say about 650HP at the crank.

850cc's will do about 1130 crank hp on race gas and about 730ish crank horsepower on E85.

If the cost is the same, go with the 850s, there is no forseeable drawback and plenty of potential for growth later. That's my opinion of course...

[CrazyTrance]

thanks for the link, thats exactly what i was looking for..

According to the pics they subaru ones are exactly the same as the brown top jecs.

Now the question is 750 or 850, i think ill endup with the 750's, although my ka-t buddy whos pushing like 700 whp on e85 is trying to talk me into switching over.

I dont know if 750s will be big enough for e85 though, i may need at minimum 850s for e85.

Sure thing. Although I think they ane talking about the KA rads in the first link. Then the second link kind of contradicts it.
Modified by CrazyTrance at 10:16 AM 10/19/2009

[elwesso]

If the cost is the same, go with the 850s, there is no forseeable drawback and plenty of potential for growth later. That's my opinion of course...

makes sense to me... From what I understand its harder to control the higher flow injectors for lower cycle times, which may have a detrimental effect on cruising MPG and idle...

[SuperHatch]

makes sense to me... From what I understand its harder to control the higher flow injectors for lower cycle times, which may have a detrimental effect on cruising MPG and idle...

This is partially an urban legend, and partially true. It has a lot to do with the type of injectors in the car. High impedence injectors require low current to open, but respond slower than low impedence injectors that require high current to open.

Since Nissans use low impedence injectors the response time is greater, allowing for more control over the injection cycle and in effect, better idle. It also allows for slightly higher duty cycles than high impedence injectors.

Bottom line is, I've seen and tuned 1600cc low impedence injectors to a perfect idle and good part throttle behavior. It's all about getting the dead time set correctly.

[Nealoc187]

Nissan uses high impedence injectors not low impedence.

I've used up to 850cc injectors on VQs and had only the most barely noticeable starting issues on bone cold start, roughness cleared up within 5-10 seconds.

With 8x750cc injectors you could make well more than 650hp at the crank. I've made 520WHP on 6x650cc deatschwerks injectors at stock fuel pressure (3.5bar) and 92% IDC on a VQ. We were able to maintain 11.0 AFR while never going over 92% IDC (I like to keep bosch and siemens deca top feeds under about 93 or 94% IDC.) JECS side feeds I try to keep under 90%.

[c-west]

the nissan rb20 rb25Sr20detVH 45

uses High inmendance side feed injectors (all the same type)

The nissanrb26ca18rnn14 sr20det

uses low impendance topfeed injectors (all the same type)

Talked with a friend of mine witch has done alot of mapping and tuning on Jap cars,and he said that the New thin style topfeed high imp. injectors are the ones to go for now.They have ALL the accurate data you need to set them up to your ecu,witch makes the best out of your fuel economy and get you a more accuratley adjustable AFR.

I belive there is a good reason why all car manufactures uses this injectorfor all new cars now.

Check out injector dynamics.

My friend is going to make complete bolt on kits with fuel rail for these injectors.He is going to make kits for the most popular nissan and toyota enginesincluding the VH45

This kit will be going on my engine within a few months.Will keep you updated.

[SuperHatch]

Nissan uses high impedence injectors not low impedence.

I've used up to 850cc injectors on VQs and had only the most barely noticeable starting issues on bone cold start, roughness cleared up within 5-10 seconds.

With 8x750cc injectors you could make well more than 650hp at the crank. I've made 520WHP on 6x650cc deatschwerks injectors at stock fuel pressure (3.5bar) and 92% IDC on a VQ. We were able to maintain 11.0 AFR while never going over 92% IDC (I like to keep bosch and siemens deca top feeds under about 93 or 94% IDC.) JECS side feeds I try to keep under 90%.

You are correct about the impedance. I spent too much time this past week in DSM mode, my mistake.

You made 520WHP with 6x650cc deatchwerks injectors on E85? That is mighty impressive. If you notice I said 1000HP on race gas, 650HP on E85. I think we had a misunderstanding.

[SuperHatch]

My friend is going to make complete bolt on kits with fuel rail for these injectors.He is going to make kits for the most popular nissan and toyota enginesincluding the VH45

I am very interested to see what your friend comes up with. Has he actually looked at a VH intake manifold? It would be tricky to physically fit a top feed injector and a fuel rail in the space available between the lower runners and the plenum...

[Nealoc187]

You are correct about the impedance. I spent too much time this past week in DSM mode, my mistake.

You made 520WHP with 6x650cc deatchwerks injectors on E85? That is mighty impressive. If you notice I said 1000HP on race gas, 650HP on E85. I think we had a misunderstanding.

Yeah i figured it was just a brain fart

The 520whp was on 93 octane. I've never done anything with E85, I didn't realize you were talking about E85 (even though I see it was right there in the sentence now that I read it again lol) - I've got no experience with it other than to know you need a lot more injector for whatever hp level you plan to run. That must have been where our lines got crossed.

[SuperHatch]

Yeah i figured it was just a brain fart

The 520whp was on 93 octane. I've never done anything with E85, I didn't realize you were talking about E85 (even though I see it was right there in the sentence now that I read it again lol) - I've got no experience with it other than to know you need a lot more injector for whatever hp level you plan to run. That must have been where our lines got crossed.

I figured you misunderstood...

A good rule of thumb (this is by no way hard and fast). If you have 650cc injectors on a 6 cylinder motor, there should be enough fuel for 650 crank HP on pump/race petrol based gas. Your number of 520WHP supports this btw.

Since a V8 has 8 injectors, it can support about 33% more HP than 650. A 4 cylinder will support 33% less.

E85 takes a lot more fuel, and that's all I know about it. For a given injector, expect only about 65% the peak HP you would have gotten on pump/race.

[hannibal]

So why use E85? I assumed it'd make MORE power than 93 octane for the same size injector.

[SuperHatch]

So why use E85? I assumed it'd make MORE power than 93 octane for the same size injector.

Bad assumption...

E85 uses MORE fuel than petrol. Petrol stoich mixture is 14.7:1 (parts of air to parts of fuel) and E85 is 9.7:1.

That means for a given cycle, there will be 50% more fuel per power stroke using E85 than petrol, that is why you need bigger injectors.

The reason to use E85 is because:

A - Its higher octane ratingB - Its higher heat absorbtion due to more fuel.

Higher octane allows more timing advance/boost and in effect more power, while higher heat capacity also allows more timing advance/boost and in effect more power.

You use E85 when you want to make race gas power for pump gas prices. Of course the fuel consumption is higher, so some of the cheaper price is negated, but the benefits outweigh the costs in this case.

[Q45tech]

Don't forget the higher air displaced by E85 volume results in 2 % or more loss.