Installing injectors and was wondering if people have tested the air-flow to the various cylinders,... and/or if tuners know which cylinders run leanest.

This data was prevalent in the last platform that I had,.. and so you knew where to do porting,.. and what cylinders to install the highest-flowing injectors.

Just wanting to know which cylinders I should put the biggest 2 injectors. Middle two?

 

You'd never do it with injectors like that.

 

install egt's in each exhaust port, then you can adjust injector trims accordingly. The IM is what throws it off.

 

Well,.. you'd have to have O2's AND EGT's in each to make adjustments like that,... timing has a big effect on EGT's,.. so no way to know if it's lean,... or retarded timing that causes high EGT's.

 

Do what?

I'm not looking to correct anything,.... rather just to get them in the most ideal locations.

If no one has done this sort of thing on this platform,... then I'll just toss them in there randomly.

 

Your know it all attitude does you no service really, you asked a question and I answered it with some legit info, didnt pull it out of my ***. EGT's are more than sufficient to provide you with the data you are asking for. Running O2's pre turbo, and different timing per cylinder really say a lot about your level of expertise. Maybe you should just leave these things up to your tuner.

 

Wow,.. sorry man. Didn't mean it that way.

I do have a mulch-channel EGT setup that i iused with my last car. but it proved pretty useless,.. as small changes in ignition timing have a very big effect on EGT. And EGT alone won't tell you which intake runners / cylinder head ports flow the most.

Most platforms DO have tables in the ECU's that have per-cylinder fuel and timing compensations in them,.. and from the factory they are not always the same cylinder to cylinder.

it is a common practice to run one cylinder with slightly more timing and slightly less fuel than the others,.. and place the knock sensor on that cylinder (so it knocks first,... allowing the ECU to read the knock as soon as it starts).

But I wasn't asking about any of that,.. rather just wanting to know if anyone had done flow-testing of the engine and could tell me what cylinders flowed the best.

No one has chimed in with any info yet,.... and that's fine. Just thought I'd ask.

My car hasn't been tuned yet,... I'm doing some projects this Winter in preparation,... including injectors. Just trying to get them in the ideal holes. But perhaps no one has done such in-depth work on these motors yet,... or at least no one that's talking.

 

Any reasonable quality injector set will be matched well enough that picking a cylinder to put it in would not be worth the effort considering you can trim fueling to each cylinder on the software side.

If you couldn't, then yes.. it would help.

 

True.

The set of ID1000's I bought had a variance of 2.8%,...

So I bought 3 replacements to tighten them up to 0.8%. I'll toss the other three.

 

why toss them. why not send them back to id for ultrasonic cleaning and flow testing?

 

They JUST came back from them. They're still sealed in the little bags.

Their flow must have changed since new,... so I replaced the 3 that were farthest out.

Which makes me wonder how much the flow of the new 3 might change over time.

Anyway,.. if anyone needs a spare ID1000 that flows;
965
977
1002, let me know. They're freshly cleaned and still in the bags from ID.

(mine are now all in the 992-998 range)

 

Consider for a moment. To answer the original question by the OP, which cyl runs leanest, i.e. flows the most air, I would ask him this question. Why do you assume that ANY of them flow more or less than a fraction of a percent or of the others under almost all load and rpm conditions? That's what things like VarioRam and VarioCam were initially invented for. In Weissach they have been at this game, developing racing engines as powerful and efficient as any in the world, on this engine platform, for 20+ years. The Mezger engine in our cars is simply a detuned and civilized version of the GT1 LeMans car. Which itself derived from the 962. Hans Mezger STARTED at Porsche in 1956! He essentially lead development of ALL Porsche turbocharged engines from the 917 till he retired in 94 after the crown jewel in our cars. Realize the boffins in Weissach have essentially unlimited time, unlimited budgets, and every available flow modeling tool and toy available to the industry, not to mention a vast database of all the collective engine design knowledge Porche has amassed over 70+ years. These engines are spec'd something like +2/-0% of rated hp output. With CAFE standards as stiff as they were even in 2007, there is no way those cyls are flowing anything other than identically for our purposes. Bottom line, put your injectors in any cyl you wish. Sleep like a baby.

Please don't take this the wrong way, but you tend to focus on minutia, and frankly, trying to impress the boards your tuning knowledge based on other platforms. That's ok I suppose, but the folks here on 6so in the turbo forums have also been at this game for a LONG time. At this point, there is very little they don't already know about the platform. What works, and perhaps more importantly what doesn't work, based on your goals. I would politely suggest you should search and read a bit more on what the other VERY successful tuners and vendors have achieved, and how they've achieved it, rather than asking a lot of questions that are a bit out in the weeds at times. There is a tremendous wealth of knowledge here, and folks are very willing to share what they know, there's no need to impress or reinvent the wheel. I'm certainly a total beginner, and have learned the gurus here aren't easily impressed anyway.

Just some thoughts.
Cheers
Mikey

 

Do what? Do what you asked to do what do you mean? As others mentioned you'd accomplish doing what you want by trimming fuel for a given port and that's that.

 

Different intakes are flow tested in this thread. No, they're not equal in flow.

 

Not sure just installing slightly higher flowing injectors would suffice. And the problem is under less than or different RPMs at which the flow was measured the higher flowing cylinders might not flow any more air than the others and then the cylinders run rich and the DME dials back fuel and leans out the cylinders with the normal flowing injectors so they run leaner than they should.

Ideally the cylinder head should be flowed on a bench and all cylinders brought into spec regarding air flow. Then all injectors matched regarding their flow rate.

There is still the possibility the cylinders will have some variation or variability in flow in the real world due to less than optimum intake manifold runner differences (or exhaust manifold differences) causing interference of one cylinder's flow vs. another's and affecting a cylinder's flow.