Hey Guys

Just thought you may find this interesting.

I just had my 510cc injectors bench tested at RC Engineering, and got the data. Each injector was tested at 3 bar and 5 bar of fuel pressure, against 1.006 bar absolute pressure (ambient pressure at torrance CA according to weather.com is 30.10 inHg).

Here it is:

------Inj 1 - Inj 2 - Inj 3 - Inj 4 - Inj 5 - Inj 6
3 bar 550cc 552cc 553cc 549cc 553cc 551cc
5 bar 720cc 721cc 722cc 720cc 722cc 720cc


So the 'rumors' that these are really 4xx cc injectors (because PE tests them at more than the industry standard 3 bar) are pretty much proven false. On the contrary...they seem to flow about 40cc higher than rated..which leads me to believe that PE/Denso's testing is done not at 3 bar but in fact at 2.75 bar...which I had heard from someone a longtime ago. No matter what, you see the data. Another thing that this test shows is that the increase in flow of the injectors is no where near proportionally increasing with fuel pressure, which is a widely held belief. If they flow 550cc at 3 bar, you would expect them to flow 550xsqrt(5bar/3bar)=~710cc. So the 720cc numbers are right on the dot! Also, you can see that they vary by less than a third of a % from their calcualted mean...NOT up to 10% of the standard tolerance for production injectors, part of the reason why they are more expensive.

These are AWESOME injectors, with 8-nozzle dual delta pattern, they idle perfectly at fuel pressure of 47psi (3.24 bar), etc... And now we know exactly what they are = 550cc!

 

Nice job...and great data...even better they plug into the factory loom and drop in with just some simple spacers...

 

Yeah forgot to mention that.... and those spacers/collars come with those injectors already!

 

On second that...I imagine this would apply to the 380cc injectors too correct? If so... and I'm sure my math might be wrong but wouldn't that yield 447 cc of fuel when run at 47 PSI of fuel pressure?

Edit: I thought I did it wrong check make my answer ~412CC sound right?

 

Well..one would really need to bench test the 380's to know they flow MORE than 380..but assuming they exhibit the same behaviour as the 510 cc, i.e. they flow 7.8% more than the rated flow, then the 380cc's would really be 408cc injectors at 3 bar, 473cc at 4 bar, and 526 cc at 5 bar. But remember, these are flow rates against 1 bar absolute. So they will flow less under boost. Let me know if you need those numbers, i wll do the calculations... but you pretty much need to take into account differential and not absolute fuel pressure.

 

Well yes of course...I'm just factoring a comparison of similar injectors. The 380s are made by Denso as well as I'm sure you know. I would certainly love to bench test those as well. The thing is the Turbonetics kit is designed to run 47 PSI under full boost. Base fuel pressure is 53 PSI and lowest measured fuel pressure under full boost was 47 PSI as measured on my car. SO with a pressure ratio of 1.54 my fuel pressure was 3.24 bar

 

Sorry just to clarify and correct me if I'm wrong

My car runs:
8 PSI= .55 bar (boost)
47 PSI= 3.24 bar (fuel pressure at .55 bar of boost)

 

I am little confused as t why the base pressure is 53 psi and it goes down to 47 psi while under boost.

Nonetheless, if it's 47 psi fuel pressure and 8 psi of boost, your differential fuel pressure is 47-8=39psi, which is (39/14.5)=2.69 bar differential.

So, the PE 380cc injectors (assuming they flow 380cc at 3 bar) would deliver (380*sqrt(2.69/3))=380*.947=359cc/min. Assuming they flow 408 cc as per the previous post, they they flow 408x.947=387cc.

All you need to do is turn up the fuel pressure, assuming you have full fuel return system. But i am thinking that you have another setup.

 

This isn't a return system so the base fuel pressure is set higher to compensate for the added boost. So the differential pressure is actually going to be higher. This was done by design to compensate for the boost pushing down the fuel pressure. Its more like 53 PSI-8PSI=45 PSI. Although in real world logging my fuel pressure is 47 PSI when at 8 psi of boost.So the differntial fuel pressure is 47 PSI or 3.24 bar. Hence the 412 I came up with...Is this incorrect?

 

No, differential fuel pressure is fuel pressure at the rail (fuel system) minus the boost, just like in my previosu post.

 

Right but if fuel pressure at the rail is 53 psi...and you apply 8 psi back against it..it would be 45 psi at the least. When I measure the fuel pressure at the condensor at idle its 53 PSI. When I measure it at a full 8 PSI its 47 PSI. SO wouldn't that be the differential pressure? Not arguing just trying to learn.

 

Awesome data gurgen...thanks for sharing. So sounds like the 510 PE's are about the same flow as 550 RC's. Another rumor dispelled!! Love it.

 

Nice work, its good to get hard facts about things like this.

 

So for those of us preparing to install 440 CC injectors, does this mean we should rethink our decision? Is there a reason to run one vs. the other on a stock motor?

 

Good point Kelly...I would love to see some flow test results on the 380s...I'm sure since they are both Denso that the testing is done just the same. If so by this math the 380s would flow ~412 at 47 PSI of fuel pressure...

 

IMO, unless you are trying to save, let's see... about $280, there is no reason to do RC imo. I am not getting paid by PE to say this. Look at the advantages, they are plug in, fit perfectly, maintain the same identical nozzle depth (to which it descends into the intake runners), points to the back of the pair of the intake valves, spraying right into the combustion chamber as the valve opens (because of the dual delta spray pattern), and not straight at the divider between the two valves.

Given that you can run these injectors at 4 bar differential ULTRA SAFELY, the 380 cc injectors willl flow at least 438cc assuming they flow 380cc at 3 bar. But if they anythign like the 510cc's, then the probably flow a little more than that.

Unless you are building a forged engine, the 380cc's are ideal. If you are buildinghte engein, then the 510's will get you into the low-mid 600's for sure, IMO.

 

Well the bonus to this for Kelly is the Turbonetics kit comes with Denso 380cc injectors out of the box...now he can go safely to 400 RWHP (assuming this is accurate) and not have to upgrade injectors like he planned.

 

one the 3S community tuners has tested denso 720s (got em on my car too) at higher pressure. i think he said he squeezed like 764 out of them or something. he was maxing them out with one of his turbo setups.

 

great info, very interesting...you are going to take this to a whole new level!!!
hey gurgen , is it frustrating trying to have any sort of intelletual conversation with others? because you definately have a better conceptual understanding of almost EVERYTHING as far as forced induction and tuning than 99.9% of the rest of the human population...
i just get to say i know when you become famous!

 

Differential pressure is the pressure difference between rail pressure and the pressure in the manifold. Because the air in the manifold is pushing against the fuel coming out of the injector it will actually push out less and that is why differential pressure is so important. You want it to rise 1psi in the rail for every psi in the manifold. This makes it much easier to meter the fuel precisely.
Gurgen this is great info. Thanks for doing that. Do you know spray pattern width in degrees? I couldn't find any answers online.