What Ted said, you have it backwards, peak torque is not the peak of fuel needs, it is at peak hp and higher RPM where fuel is needed the most, and where the IDC's are the highest. Log the IDC curve sometime and you will see it increases with RPM, not decreases like IPW does. Maybe you are confusing IDC with IPW? RPM x IPW / 1200 = IDC

Spool has nothing to do with peak IDC's and is not even close to to stressing the demands of a fuel system.

If you are not maxing out a fuel system with a single pump and 1000cc's on a 35R, then you are not even close to the true power potential of that turbo on E85.

 

~95% IDC at 25-26psi, with my 950's.


More pump and injector to come though. Gotta love e85

 

If you read David B's post when he said the IDC'S on the 1600's were maxed out on sheps car, when they made 596. He later figured out that idc's were not his problem, but fuel pressure to the rail was! This is what i base my opinion on. Ted said it right when he said "Fuel demand is a function of mass airflow". I have one car with a 35r that made 520hp and 420tor on single pump and 1000cc fic's and it was out of fuel up top. But on the other hand a tme wr with rc 1200's making 460hp and 450tork had just enough fuel to get peak tork, but plenty fuel up top. In my experience with e85, the fuel is heavier which takes longer to get the the fuel rail and you need so much more of it to power the car. Thats why i believe fuel pressure is the main problem with e85. You cant think of fuel pressure like its 93 or race gas, this is a whole new ball game now. Different flow and weight!


I agree Ted, it will take more fuel to power bigger turbos! But it will take more flow to power the red compared to the bigger turbo. I have 4 stock turbo set-ups and 5 big turbo set-ups in my area all running e85 and all the fuel problems are the same.

 

Its funny you say that, the hta 88 car has got 1200cc's and made 565hp at only 28psi. HE picked up 45 whp and all from going from 1000's to 1200's. Now the car is getting a motor build and already has 1600's installed. So with the br double pumper and 1600's on the stock ecu we shall see what 7 to 10 more psi puts down. Remember i did say our dyno reads high, but it produces numbers close to a dynojet. I just want to see the true potential of the hta88 on e85.

 

Ok I really think there is a communication problem here. You contradict yourself a couple times in this paragraph.

What are you basing "out of fuel" at peak *torque* off of? IDC? IPW? Fuel pressure?

 

A single pump maxes around 470 on a proper reading mustang with a good flowing turbo on E85, so yes that mustang reads very high.

 

you cant get a red to make 470 on any dyno without the doublepumps. It takes more fuel when you spike the boost! I will put it plain. You need more fuel pressure with a faster spooling turbo and less with a bigger turbo. Twin pumps are for smaller turbos and single pumps will work with bigger turbos to make your 470hp!

Razor, i know you have tuned alot of cars with different set-ups on e85 right? Then you will understand when i say this fuel is different in alot of ways! Flow rate, weight, density, and volume to spark the fire!

 

Single pumps with larger turbo turbos but dual pumps with smaller turbos is **** backwards.

Now you are back tracking and saying fuel pressure where before it was fuel requirements and single/double pumpers. Maybe show some logs to back up this argument?

Ok I am just going to agree to disagree on this one.

 

Regardless of power numbers:

Ethanol weighs 6.59 lbs per gallon, 1000s will only flow 240lph at 100IDC

240 liters=63.5 gallons which means its 418.465 lbs per hour

Formula SAE list BSFC at .7142 for E85

418.465/.7142=585.92 BHP not WHP

However a single pump doesnt flow 240lph at the boost level it takes to make 585bhp so a single pump will be much less. I am not going to argue the semantics of WHP just what brake horsepower should be flowed. Using RC engineering's calculator actually shows less than those numbers for reference.

I have observed 35R car being able to support 25-26psi on 1000s and one pump and only slightly better on 1000s and 2 pumps (27-28).

 

My point is that unless you have a built motor there is no sense in having twin pumps on a big turbo, one pump will make plenty of power for the stock bottom end! but two pumps are nessary to do at least 25 to 30 psi on the red if you want to run that much boost! Now on the stock bottom end with all bolt-ons and the red 30 psi , 1200's and twin pumps will be the breaking point on e85. But with one single pump and 1000's you could not make over 370 on buschurs md! With the bigger turbo and 1000's with single pump you could make around 440 on br dyno.

 

Ok so now a built motor is in the equation on how much power you can make and now we are talking about yet another dyno make and location. I can't keep up with your changing points.

Again, I'm agreeing to disagree with this and don't see the point for me to keep discussing this further if the points are shifting every post.

Have a safe and happy holiday.

 

SpoolnupTuning, quit while your ahead. I don't have time to read this multipage ****fest but in the last 10 posts that I've read I can tell that you are wrong and to top it off your arguing with guys who have done it and are continuing to do it.

 

yeah ST its ok man, but youre starting to look really evasive

 

The pump size has nothing to do with the boost spike, unless you are using a fuel pump that dramatically falls off in flow at the boost spike pressures. The mass airflow at lower RPMs is way too low at that point to max out the fuel pump. The point where the pump will begin to fall off in supply is at the highest mass airflows, which occur at the upper RPM ranges where max HP is. The fuel pump just needs to be able to supply enough mass flow of fuel to match the mass airflow for the intended AFR.

Why you think a single pump isn't enough for a smaller turbo's boost spike doesn't make sense. Dual pumps are only needed for the bigger turbos than sustain a higher mass airflow in the upper RPM ranges.

Here's a little math for you to help understand, and you can tell us where you disagree:

Let's say that we have a Red turbo that gets to 30 psi at 4000 RPM. Let's calculate the mass airflow at 4000 RPM and let's say we can hold that 30 psi to a 7500 RPM redline.

Airflow (CFM) = PR[RPM*V.E.*Cid/3456]
Airflow(lb/min)=(Airflow(CFM)*P/RT)*294000 RPM (assume .95 VE, 14.7 baro, 100F IAT):
Airflow (CFM) = 3.04[4000*.95*122/3456]=408CFM
Airflow(lb/min)=(408*14.7/10.73*560)*29=29 lb/min of airflow

7500 RPM (assume .90 VE, 14.5 baro, 120 IAT)
Airflow (CFM) = 3.04[7500*.90*122/3456]=724CFM
Airflow(lb/min)=(724*14.5/10.73*580)*29=49 lb/min of airflow

So, at 7500 RPM you are flowing 69% more air than at 4000 RPM. And you're trying to say that the fuel pump is going to have a harder time providing enough fuel to match the mass airflow at 4000RPM than it is at 7500 RPM? That doesn't make sense to me.

Even if we were to go to extremes and say that the turbo spiked to 30 psi and dropped to 20 psi at redline, the fuel supply demand would still be 31% greater at redline for 20psi than at 30 psi at 4000 RPM. Looking at a common fuel pump (the walbro 255), the flow of the pump only drops about 12-15% from 20psi to 30 psi of boost pressure (63-73 psi fuel pressure). So, if the fuel pump can support 20 psi at redline, it has plenty of capacity to supply 30 psi at 4000 RPM.

 

This has been by far the most beneficial post in this entire thread. I had to ask my wife (who knows nothing about EVOs) if several posts made sense and even to her it didn't sound right. I appreciate the humor and sometimes we all suffer for a case of pride, stubbornness, and intellectual arrogance.