rl

What walbro pump are you running? How much boost? Do you have any idea what the BSFC for your engine is? I would assume it's in the .65 range..? We can easily figure out if you need more pump... Regardless, if you are running out of fuel pressure a walbro in-line will fix the problem, it wont raise the pressure either, just allow it to maintain the pressure it requires when you are under boost with that amount of flow. The reason it is running out of pressure is because the single pump cannot maintain flow that is required at the pressure you are running (I'm assuming over 60psi of FP while under boost).

Flowing into a bucket is not a good measure of anything, it needs to be a pressurized system to work correctly. An in-line pump is NOT a band aid for injectors that are to small, that's called an FMU, an in-line fuel pump is used to support more power and flow MORE fuel at MORE pressure (if needed, like in boosted applications). In a return system that has an adequate FPR and fuel lines the fuel pressure should not raise with an in-line pump. The only way adding an in-line pump will increase pressure in a return system is if it outflows the capacity of the return or the FPR, otherwise it allows you to move more volume at greater pressure (with a FMU or AFPR), but it also allows you to move more volume period. Your dealing with a pressure drop across the pump, so say you have a single pump, atmospheric on one side and 42psi on the other, you now have a 42psi pressure drop across the pump. The problem for someone like Chris is that he is running probably 42psi base pressure, but to keep the pressure drop at 42psi across the injector under boost the FPR raises the pressure on a 1:1 ratio with boost, so if he is running 20psi, he is now running 62psi (yet the injectors flow just as much as they would under 42psi, the FPR compensates for the pressure at the tip of the injector). What happens when you have a 62psi pressure drop across a single 255lph pump rated at 40psi? You lose a significant amount of flow. Now- 40psi/(42psi+20psi boost) = .65 sqrt.65 = .806 806*255 = 205.53 So you how now effectively turned your 255lph pump into a 205lph pump. Now lets say that you have a 255lph in-tank pump and add a second 255lph in-line pump. The only real way to measure this is to take the pressure between the pumps, but since this is hypothetical, we'll say that there is 20psi between the pumps. Now- 40/22+20 (using 20 because the pressure drop across the pumps is now 20 instead of 42) = .95 sqrt .95 = .974 .974*255 = 248.37 for each of the pumps. You now have over 400lph of fuel FLOW at the given pressure, as opposed to the 205lph of FLOW that you had before with a single pump. Of course the calculations all change with a 255lph high pressure pump (they are rated at 60psi I think), but the ideas are exactly the same. Its basically repeating what is said in that link, read the link if what I said doesn't make sense to you. Chris, are you losing fuel pressure in 3rd gear? If so an in-line pump is what will fix the problem correctly. Rob:) [ 18. February 2004, 09:27 AM: Message edited by: rl ]

http://www.modulardepot.com/?show=articlesdet&aid=24 Read smile.gif The guy who wrote it knows what he is talking about. Desperado basically said everything I would have said, he is 100% correct.

smile.gif

Yep, on any of them with a VSS instead of a speedo gear. If its a speedo gear you're outa luck. 96+ we can for sure, not positive with the older ones. We also do it CORRECTLY in the EEC. With an Abbot ERA or speedcal that alters the VSS signal the tranny doesnt work right.

We are offering tuning for Ford 7.3L powerstroke trucks now. The average gains are 70+rwhp and 150+ rwtq, right now the 'good' tune makes 90hp over stock and 190ft/lbs over stock on the test truck, with JUST a tune on a stock 7.3L. We have 2 stages of tunes below that as well. Cost for a single program chip and dynotune (including dynotime) is $430. Cost for a 4 program chip and dynotune is $550. We can also tune V10 trucks with impressive gains. Last weekend we saw 15hp and 25+ ft/lb gains, not to mention area under the curve. The prices are the same for the V10 trucks. The 6.0L power stroke tunes are coming soon.... Call us at (740) 971-4901 to set up an appointment! Rob LaSota www.lasotaracing.com [ 02. February 2004, 06:20 PM: Message edited by: rl ]

The battery terminals are dirty. Remove them, clean them, and put them on again tight. Rob

Adjusting timing, getting the AFR correct, and fixing a few other things from the factory.

We can Dynotune it for you, Ford left a lot on the table with tunes in those cars, we can flash the EEC or burn a chip (even a multi-position chip). smile.gif

I make intercooler pipes, I've done them for a few people on here who can attest for my work. I'll build them and powdercoat them any color you want for a lot less than you would think. Email me or call me rob@lasotaracing.com (740) 971-4901 Rob

What that guy said. It wouldnt be very strong either.

Internal Combustion Engine's

Ditto. If you want it done right, he'll do it.

24's or 24's depending on the combo. For a basically stock car autolite 25's are perfect.

It holds true even with a race car...

Well put. We generally do a 11.5 target, with a little more fuel at the torque peak. With a Honda system you have the problem of the AFR changing day to day due to air, I always tune rich with Honda's. With the Ford systems we use they have adaptive learning, it calculates how much it must compensate to achieve 14.7 at idle and it uses this information and applies a correction across the entire curve. If you tune the car correctly then the adaptive will keep the AFR right where you have it targeted, so it could be a 100* day or a 20* day and it would maintain the same AFR. It is a little more complex than that and takes in a LOT more variables, but you get the idea. smile.gif Not that this has any relevance to anything in this thread. I'm very partial to MAF systems. lean =/= mean. Dont listen to what you read on the internet message boards, go read some books on ICE's.

13's are breaking ring lands if it detonates at all. Especially if your just using a piggy-back system on a stock Honda ECU. Leaner is not always meaner, you'll find power running more fuel a LOT of the time.

Tuning a street car that close to the 'edge' is not the best idea ever.

It'd be close with a normal 1.90 head, the TFS heads would probably hit. What about trading it for another cam? FWIW, We just tuned a fox car with a strock shortblock, fox lake ported edlebrock heads, a edlebrock intake, a crane 2040 cam, 24# & pro-M injectors and a full exhaust and it made 300rwhp and 321ft/lbs on a mustang dyno. smile.gif

Probably another hose.

If you need help let me know. I have an Auto-tap we can hook it up to and figure out whats going on.

What he said.

Your good to go Brian...but you already knew that!

We'll have our 4 position flip chips and flashers within the next 2 weeks guys!!! smile.gif Rob (740) 971-4901

You think its making 550-600hp and its only trapping 121? With that kind of power you should be trapping 125+ and going low 10's. You probably wouldnt see a gain going to a 75mm+ throttle body.