Do I really have a fuel starvation issue (E85-but not only)

[Christos Adam]

In the past I dyno-tuned my turbocharged miata at 287 whp on 91 gas 550cc injectors and my Walbro 190 HP fuel pump w/o any fueling issues. Before switching to E85 I got 4 new 1000cc/min injectors and I kept the Walbro 190 HP pump.

Since yesterday I'm officially running E85. I haven't pushed the car but that will happen on Saturday during the new dyno/tuning session.Going back a few hours earlier today I had some communication with Bill S which made me think again about my fueling needs...so I went ahead and did some rough calculations, the results were shocking and it seems that my system is not capable on handling the increased fueling needs of the E85 - furthermore things got even more weird because I did an analysis on my previous set up my calculations showed again that it wasn't adequate (even though I never had a problem). That makes me believe that (hopefully) I'm doing something wrong in my calculations.

Here is my analysis:

The Walbro 190 HP pump can provide 190lbs/ hour or 110.7 lit E85/hour (this is with 0.78 specific gravity for E85 - very close but a bit heavier than 87 gas 0.72-0.76, 1 for water)
4 injectors 1000cc/min or 1 liter/min gives us 4 lit/ min or 240 lit/hour
Of course the injectors won't be utilized 100% but probably around 80% which still gives us 192lit/ hour. It seems that the fuel pump can only support these injectors on 46% utilization .

Same analysis on 91 gas shows that the fuel pump can't support my 550cc injectors (utilized at 91%)

[Marshall Grice]

you're mistake is that the numbers in the walboro part numbers are in l/hr.

something to note is that the pump doesn't provide 190l/hr for all fuel pressures and if you're turbo'd your fuel pump will see higher than the base pressure when in boost thus reducing the flow rate below the "rated" flow rate.

here are some general numbers.
http://roadraceengineering.com/fuelpumpflowrates.htm" onclick="window.open(this.href);return false;

[Christos Adam]

Thank you so much Marshall, that explains everything and makes me happy that I would probably be fine with the current fueling system...

[Kurt Rahn]

you're mistake is that the numbers in the walboro part numbers are in l/hr.

something to note is that the pump doesn't provide 190l/hr for all fuel pressures and if you're turbo'd your fuel pump will see higher than the base pressure when in boost thus reducing the flow rate below the "rated" flow rate.

here are some general numbers.
http://roadraceengineering.com/fuelpumpflowrates.htm" onclick="window.open(this.href);return false;

Thank God you're not an engine guy }:)

[Marshall Grice]

Thank God you're not an engine guy }:)

come on now, that's not even engines. everyone knows how to size a fuel pump...right?

[Christos Adam]

Thank God you're not an engine guy }:)

come on now, that's not even engines. everyone knows how to size a fuel pump...right?

I guess I'm not everyone
...
or if I see it in a positive way maybe I'm special right? }:) :mrt:

[Christos Adam]

By the way I got a Walbro 255 HP today - just to give myself a bit of a margin since the 190 HP will totally be at the border line with the current set up...

I just need to find some time tonight to J-B Weld my alternator and install an oil cooler - and I should be good to go to dyno session...

[Jonathan Lugod]

By the way I got a Walbro 255 HP today - just to give myself a bit of a margin since the 190 HP will totally be at the border line with the current set up...

I just need to find some time tonight to J-B Weld my alternator and install an oil cooler - and I should be good to go to dyno session...

[Aaron Goldsmith]

Yo dog, I heard you like JB Weld...

[Christos Adam]

LOL

I wish I had a better answer but all the above are very true.

I don't know how but there was a wobbly bolt in my alternator which made the hole for the alternator bracket to change from a circle to an eclipse shape. That by itself created tension to the bracket and cracked the piece of the bracket at the alternator side.
The problem is that the bracket for the alternator is part of the oil pump so to replace the bracket I need to pull the motor :barf: .
I tried to re-sleeve the hole with another cylindrical piece of metal and didn't work out. I need to revisit this again - unfortunately since there is oil in the engine I can't weld a sleeve in the alternator bracket hole - so it's seems that my only option is J-B weld.

I'm open for any other (brighter) ideas :ibrightdea:

[George Doganis]

Back in 2005, one week before Nationals, I decided to replace my oil pressure sensor. Well, the block casting where the pressure sensor threads in, broke off the block(the mechanic had tightened it so much that it had cracked )!!! So, Tom S. comes to my rescue and suggests that I JB Weld the block back together. And so I did. And not only it worked, but I won CSP Nationals in my Miata a week later(no protest of my JB welded block). And, up until I replaced the engine this year, the JB Weld never leaked while holding full oil pressure for all these years.

All of you young ones, need to feel, and become the "force of JB Weld". Once you master that you may win some championships. Christos is definitely on the right track.

George

[Steve Lepper]

Even better than JB Weld is Marine-Tex.

I've seen it used permanently on engine block / cylinder head repairs with no problem. Also, it's what the air-cooled VW guys use to fill in around the intake ports before porting (because they port clear through the casting and into the M-T.) If it's strong enough for that, it should hold your alternator bolt.

Just be sure to allow adequate curing time: add more time if it's in a cold garage.

[Sebastian Rios]

I'm gonna pickup some JB Weld on my way home tonight...

[Jonathan Lugod]

I'm gonna pickup some JB Weld on my way home tonight...

i don't think thats going to fix your hamsters seb.

[Christos Adam]

Back in 2005, one week before Nationals, I decided to replace my oil pressure sensor. Well, the block casting where the pressure sensor threads in, broke off the block(the mechanic had tightened it so much that it had cracked )!!! So, Tom S. comes to my rescue and suggests that I JB Weld the block back together. And so I did. And not only it worked, but I won CSP Nationals in my Miata a week later(no protest of my JB welded block). And, up until I replaced the engine this year, the JB Weld never leaked while holding full oil pressure for all these years.

All of you young ones, need to feel, and become the "force of JB Weld". Once you master that you may win some championships. Christos is definitely on the right track.

George

Thank you for your support George, as you predicted J-B Weld also worked for me
I put the car together this morning (left adequate curing time according to Steve's advice) and headed to Church (Automotive).
I was 1 hour late due to the heavy rain and then my LINK ECU boost control was malfunction but eventually Sean manually set the boost limit at ~17 psi and he easily got almost 20hp improvement over 91 pump gas. This time I got 306 wHP with faster spool up and better torque!

please let me know If any of you guys can open the apg dyno files for me - I have the previous version of Dynapack installed at my pc so I can't open the newer apb files