proper atomization is the question... is this the Holy Grail or BS?

 

Bob:

About 18 months ago I was lucky enough to sit next to the guy at dinner who was a part of the team that put together the MCS upgrade package for Dinan- in fact it was his car that was the "mule".

The fuel pump issue came up. He believes the issue was an anomaly in his car that has not yet been replicated.

In other words, the modification was probably influenced by the beta tester's faulty pump - not an actual documented fuel delivery issue inherent to the car.

If you would like, I can give you the guy's contact info (offline). You can ask him for yourself.

 

atomization is important. The better the atomization the safer the car can be and it will make more power... but.. there are wayz around this with really big injectors...

 

and economy.

Now, there are tons of existance proofs that its not needed, but who knows if higher pressures and shorter durations make for any difference or not? I sure don't......

But you run into another limit as the fuel pressures get higher. It's what the injector has to open against, and higher pressures slow down opening times. Tweaking the rail pressure is a common trick in some other tuning circles, and I'm actually surprised no one has done it as a poor mans way to lean the car during WOT.....

There are lots of injector capacity calculators out on the web. Just remember to put in the motors gross HP (before blower drive loss), as that's the amount of usable chemical energy you need to release, not the crank HP, what you get to use.....

These will get you close. Then you can see what's available, and what you can tweak with pressure changes.....

And then you stick em in and tune er up and hope for the best. Just like always!

Matt

 

HMMMMM

 

Do we know that a 380 is the next best step with a pulley, CAI, exhaust, bigger IC? IMHO, yes. Does fule presure play a big part with the bigger injectors? At 380, I don't think so. Dinans solution is simple & cost efficent. However, I don't agree with it ( I agree it works ). Matt mentioned duty cycle as well as flow. The larger injector wins over high presure on both counts.

 

so is the consensus that with 440s and safe A/F ratios that this is probably not worth chasing?

 

Say it ain't so! For all the bragging I've always heard about Dinan's rigorous testing, if their package includes parts that are present because the car (singular) they used as a mule had a fuel delivery problem... That's disappointing.

Please tell me they tested their package on numerous cars and encountered this issue with more than one. If not, well... It makes me kinda sad, ya know.

 

Both Randy Webb and I heard the same story - straight from the source and in the flesh. I have given Bob the contact info and he can check it out for himself. Whether there is some meat to the story or not - we may never know.

Do you not think that it is odd that no one else has run into this fuel delivery issue, considering the mod work that Tuls and company have done?

 

Hold on, their solution DOES work, I just don't agree with it.

 

Again, the same as what I heard - I know which Vendor it was. We were sitting next to each other at the time.

 

the JCW 210 kit steps up to larger injectors. The Dinan doesn't but tweaks fuel pressures. What's the big deal? Same effect, different solution....

In fact, the latter is a way to add more fuel that oddly doesn't need to have an ECU reprogram for good idle and closed loop operation, as the injectors haven't changed, and the difference from fuel rail pressure really only comes on when under boost, and the car is open loop... Hmmmmmm

Matt

 

440s are in line with your mods. There is much more potential HP & TQ than what I have, or looking for. As long as you can manage AF & emisions, bigger is alyays better. If I could get 200whp with what I have I would be very happy. You, on the other hand, could break +250 very drivable horses.

 

In order to take advantage of their mod, their software is needed. The upstream O2 sensor does see the extra fuel.
You can use 380s without a tune & possibly see some improvement ( they made a difference on this car ).

 

The most important issue in this thread seems to have been ignored: drivability. Drivability not only trumps peak horsepower at the road race track but on the street as well. From my experience, injectors larger than 400cc have both idle and cruise issues. Fuel puddles in the trough; it does not atomize well.
However, it seems Fireball has no issues with larger injectors because they posted in another thread that they utilize up to 650cc injectors in stock based cars with no drivability or OBDII issues. That is 63% larger than Dinan, MTH, Wegner, or I recommend. (At this level of injector size the issue is not MTH or Dimsport software based; it's a physical limitation. Remember, we are talking about 400cc cylinders!)
I tend to err on the side of safety and when more fuel is needed by whatever car I am tuning I simply add anther injector.

 

we are going to drag this one out again? you might want to reconsider... or just go visit the last thread about this...

the next thing i would recomend to you is to go cruise the honda forums or the supra forums before you start talking about cylinder size and fuel injector size... there are hondas with 1000+ cc injectors on 1600cc engines... and guess what they idle perfect and drive perfect!!!! spend sometime cruising around some of the other forums... you might learn that what you said is not entirely accurate all of the time.

 

As I have said before you, Fireballs and a few others seem gifted: you guys see things I do not (my data shows an average MCS makes 140 WHP; you guys have seen on numerous occasions more power at the wheels than BMW sees at the crank), you guys can do things I cannot (such as make 650cc injectors atomize fuel in a stock MCS with ease). What more can I say other than I cannot compete at your level (there are hondas with 1000+ cc injectors on 1600cc engines... and guess what they idle perfect and drive perfect!!!!).
I know: I not happy I joined another thread in which irrationality seems to be the rule. Same guys; same result. In threads like this speculation is completely removed as to why Dinan and other tuners don’t play here. (As a matter of fact, the irrationality is also why people like Andy Ross get driven away. And do not worry; soon me.)

 

Where do they play? Average readers who have little to contribute mechanically, or religiously as some alliances to vendors go, get sick of all the BS, too!

mb

 

Are F-1 cars driveable?

 

I just added the JCW injectors this weekend, and I'm pleasantly surprised at the improvement without any ECU changes. The car starts faster, pulls harder at 1/4-3/4 throttle, and idles perfectly. WOT seems about the same, which seems odd since that is where the stock injectors should be running out of room. I'm curious to know how much GIAC/MTH/Unichip could add, because I'm pretty happy with the car now.

 

Not again.

It is very true that injectors over 400cc are extreemely dificut manage for the Mini application. You are taking a design that is designed to atomize at a much higer air volumn and make the nozzle react as if it was smaller cc untill the demand allows for, its, design spec. Don is simply saying that this is an area that MTH does not address with an injector over 400cc, it might at a later date. I understand Dons concern as to the practical use of very oversized injectors for such a small cylinder capacity. Without proper management "too big" is an even bigger problem, driveablity, emissions, etc.

On the other hand check out the injectors on a top fuel dragster, how many & what they are used for.

 

not really.... according to my friend who races a 3000 with an F1 engine they are a handful... but I would not know personally

 

at speed, they seem fine... But at Monterey, the Toyota F1 car seemed to sputter and spit unitl somewhere north of 7000 RPM or so.... Wouldn't want to drive it in bumper to bumper....

And for the injector stuff. This is all interesting to me. From my Mustang days, larger injectors were hard to control for idle as they didn't really open and close that well for the very short durations that are needed for a good idle. The notion of needing so big an injector (and the comparisons to dragsters just doesn't hold. They don't plan to have them run for years without tuning or cleaning) that you can't control it for idle, and the task of getting really large fuel delivery with either a secondary set of injectors or a huge throttle body injector isn't new or uncommon.

I'm also frankly baffled at what our injectors are actually doing! One data logging session I did the ECU thought it was opening the injector for over 120% of a camshaft rotation! It would need a time machine to make that happen. So while the 380s seem to have some life in them, I really don't know what the duty cycle is.

I'd be very curious about how to get 1000cc injectors to idle well without really dropping fuel pressure to them!

Matt

 

I have 1st hand info on the the Alta/Walboro 255 pump as I installed it in my tank. It does drop in with no modification other than the electrical connectors. You can see pix in my gallery. The only issue I have with it is how it sits in the carrier. The stock fuel pump sits under the lid of the carrier not on top of it like the Walboro pump. I found this out to my dismay when trying to remove the stock pump. The issue with the Walboro sitting on top is it doesnt sit as low in the tank. So now I dont get to suck up all the fuel in my tank like before. I have the Nav system, so I have the little led fuel bars. When I get to the last bar, I can not go my 30~40 miles like before safely. I need to stop ASAP or run the risk of running out of fuel.(which coincidently has happend thrice!)

 

did you "need" the new pump for the 550s.....