OK,Then please explain to me that it had 70 in the midrange,the highest TQ,,,,But then it went down to 65 when the peak TQ was falling and thats when it was nearing peak HP???

 

Well, if you go by the standard equation for fuel flow = hp*BSFC/#inj*DC then max flow would occur at peak hp assuming everything else being constant.

 

I don't see how that equation supports the statement that max flow would occur at peak hp ? I think that formula is used to determin what size injector to use.

I am not say the statement isnt correct, just not sure I understand how the equation supports it.

Also what are you using for your BSFC ? A estimate for turbo motors or actual results from your Dyno testing ?

 

I have to admit that I probably have the least hands on experience than most on this forum. So please take whatever I say as "theoretical"--
As for the equation, the units are quantity/time, i.e. lbs/hour which is flow. Based on this, max flow would occur at max hp assuming BSFC and duty cycle remain constant. When people say they are running out of injector/fuel, they usually are referring to the upper hp end. An average BSFC of 0.65 is generally accepted for turbocharged engines. This value can change, however, depending on the tune and how rich or lean the tune is running at a given load/rpm.

 

.65 is a generally accepted BFSC figure for a turbo engine. So what we are estimating in that formula is the hp figure. Doing so allows you to calculate the injector size needed. .8 is the DC ( duty cycle ) figure commonly used.

My hands on experience is in designing systems for off road race cars and not so much the hypothetical or Dyno side of things figuring out how to supply hp engines, more in how to make the system work in extreme environments of Baja 1000 type racing where you have to deal with steep angles, dirty environments, high heat, radical vibration, the constant change in the vehicles attitude. ( bouncing around at high speeds over 2 foot whoops , sever off camber angles and such )

So I don't have any first hand experience with the Porsche turbo motor and it's specific horsepower and fuel requirements. But if you want it to run while the car is on it's side or climbing a 60* incline I am your guy..... Lmao

My comments to dgreen however are still very relevant as it doesn't matter if the system is for a 800 hp trophy truck or a Porsche race car. Plumbing is plumbing and the same issues arise and have to be delt with.

 

On a side note, the porsche in tank "monster" or octopus as you guys call it is looks like a nice piece of engineering. Pretty straight forward setup.


Somebody mentioned a cooler. Is the cooler standard on these cars ? And does it come from the factory on the return side ?

Somebody mentioned that theirs was hooked up to the return to tank.
This makes no sense to me and I have a hard time believing Porsche would do this.

 

John, What are your AFR's at those points? I have always had leaning issues at torque peak rather then hp peak. That is also how you see improper fuel delivery on a motor, lean in the torque peak and the afr's make a rough rather than a smooth line at the top end. I do not know the math on this because if you have the right fuel system for your needs it is no problem, My thought on it is that if you are using 65% @ 3500 rpm and 70% @ 7000 rpm then you are using more fuel at 3500 verse air flow compared to 70% at 7000. The motor is an air pump and in theory the faster it spins the more air it moves, with that theory you should be 40% @ 3500 rpm and 80% @ 7000 rpm. That is not the case at all though.

 

Hi,I do not have the charts with me,they are at Kelly Moss Racing.I will be going back there or I can find out from Tony at EPL. . But...as I recall,they were richer in the mid,peak TQ area and then went lean as the RPMS were climbing....With Carbureted non turbo vehicles on the dyno,,,I always had to jet up, as I went past peak TQ range to achieve the right A/R to make max HP in the higher RPM band,,But then again with my engine builds I made more max HP then max TQ.....Thanks for your info,,,,Just my info now.......

 

I never really was involved with tuning a carb on a car but have seen it done. They would dyno to get close then the track, they would jet it back until the mph would stop increasing then fatten her up one jet. I was told they have to do that just about every race day as temp, altitude, and humidity play a big part. I did mess with the flat slides on my old bikes and jetski's but that was years ago and I was using pyrometers...

 

HEY Guys,,,,Kelly Moss Racing,Wisc.,Just made a plug in kit to add an extra fuel pump on my car.It leaves the stock one in tank ,leaves the filter in the original location,,,,they found a safe place between the the two and use factory connectors....Have not be there to see it yet.......I will be putting it on the dyno and hoping Tony/EPL will do his magic with this ,as he said I needed this......I will keep you posted.....

 

Yes they called me I sent them the connector lol now they just have to place the pump somewhere... without it they cant direct fit ... I cnc machined that part.
good luck
mark

 

10 people will skin a cat 10 different ways!

 

yup!
great talking to you today, Tim!

 

I always find it best to go right to the source, none better than Markski.

 

LOL

Always good to hear from you. Funny the way things work..