880cc injectors walbro 190 and dsmlink

[thewraith]

Hi all,

Well my little ebay turbo is running great right now. But I have 880cc injectors coming in with dsmlink now. I have a walbro 190 and an ebay 16g. My question is whether I will need a fpr to run the 880's with my setup? I am only aiming for about 20psi boost. Or do I need to get an fpr for this? I was hoping dsmlink would help compensate.

thanks
meek

 

[Black95TSIawd]

An adjustable FPR is for the fuel pump, not the injectors. Unless you want to make your injectors run more or less then what they are rated for via raising or lowering the base pressure. In a 2g's sake, overruning the FPR is more of a problem with the siphon in the tank. Because we have saddlebag gas tanks, a siphon is used to extract fuel from the drivers to the passenger's side in order to get the fuel to the fuel pump assembly. This siphon is tiny. I currently have warlbro 190 and have 50psi base pressure. Does my car run? Yes, but not being able to manually control the fuel pressure does not help in fine tuning.

 

[thewraith]

Ok a little clearing up needed here. I know the fpr is for the fuel pump and not the injectors. But what I'm wondering is whether the 190 will be able to properly send enough fuel to my 880cc injectors to fuel them for 20psi of boost. Or if it will even be needed. What do you suggest in my case? I have a walbro 255 too brand new in packaging but didn't install that.

 

[2GEcpliseluvr]

The 190 with a rewire kit should do fine to run 20 psi.

 

[Black95TSIawd]

Throw any amount of boost at a 16g, and a 190 will be up to par on gasoline.

 

[fwspin]

If I were running 550cc or even 660cc injectors i would run a walbro 190. With 880cc injectors I myself would upgrade to a walbro 255 and a FPR. Also may I ask why 880cc's thats a little over kill for for a 16g don't you think? Yes I know link will compensate for them but that means the duty cycle will just be set low. The only thing i can think of is you decided to go big now so you didn't have to buy new injectors when you upgrade again.

 

[thewraith]

Hi fwspin,

Yes- I will go 20g or bigger if this ebay turbo craps out on me, which I doubt it will in the next few years. Plus I picked the 880's up for a great price. I do have a walbro 255 but currently using the 190 since I wasn't planning to originally go with the 880's.

thanks
meek

 

[wret]

It is likely that you have more injector than you are actually using. Ultimately the fuel pump needs to be sized according to your maximum horsepower and maximum boost.

Here's the fuel counsumption calculation boiled down:
HP x 0.42 = max fuel consumption rate (in liters per hour)

So if your output is 300 HP:
300 x 0.42 = 126 lph

This is pushing it a little close for a Walbro 190 at 20 psi boost.

 

[Splitpi]

Wret is correct ... for a more accurate calculation that factors in Boost Pressure (which translates to fuel pressure due to 1:1 boost to fuel pressure), use these calculations:

http://www.dsmtuners.com/forums/newbie-forum/275824-fuel-injector-question.html#post151334548

A 190 with a rewire on a 2G (at stock base fuel Pressure) at 20 psi flows around 141.3 ltr/hr or enough for 588 cc/min injectors at 80% duty cycle... give or take 10% exactness and interpolation.

A 190 without a rewire on a 2G (at stock base fuel Pressure) at 20 psi flows around 124.5 ltr/hr or enough for 518 cc/min injectors at 80% duty cycle... give or take 10% exactness and interpolation.

This is the max output flow the 190 can give and feed your injectors... irregardless of the injector size.

A 190 with a rewire on a 1G (at stock 1G base fuel pressure) at 20 psi flows around 165.8 ltr/hr or enough for 690 cc/min injectors at 80% duty cycle. Note: injectors are usually rated at 43.5 psi... so when used on a 1G the flow decreases due to lowered based fuel pressure. i.e. 550cc on a 1G = 507 cc on a 2G. Thus the 690 cc/min would require 748 cc injectors on a 1G ... but only flow 690 cc. The resone is the base fuel pressure. By dropping the fuel pressure, the little wally 190 can supply more fuel. However, as you drop the base fuel pressure the injectors actually flow less fuel, so you must compensate with even larger injectors. Though in this case the drop in fuel pressure more than compensates and as you can see with an apples to apples comparison by dropping the fuel pressure from 43.5 to 37 psi the wally 190 can 690 cc/min injectors versus 588 cc/min. Though for the 1G you must run 750 cc/min injectors to get the 690 cc/min flow.

Also note these are the maximum flow rates of the pump and I personally would never push them that close to the edge.

 

[thewraith]

Thanks for the clarifications fellas, I will keep you updated on what happens with everything.

thanks again
meek

 

[wret]

Walbro makes the 190 and 255 pumps in regular and high pressure models. I didn't know this when I bought mine but I believe the typical 190 pump sold for DSM's is not the high pressure model. The 255's are available in both regular and HP.

Here is some flow data for Walbro 190 and 255 lph pumps at 12v and 13.5v.

 

[Splitpi]

Wret... where did you get the data for the chart? Off hand, it looks like the data differs significantly from that posted by RRE's findings here.

I'm not saying yours is wrong and they are right, I'm just trying to figure out the differences. For instance according to RRE a 190 at 14v (13.5 could be considered 14v for rough analysis) at 43 psi = 208.83 ltr/hr @ 58 psi = 162.78 @ 73 psi = 104.10. I.e they show a significant flow drop by 73 psi (half the flow has dropped off) but your data shows ~160 ltr/hr still or just a 23% drop.

 

[wret]

I got the data from Auto Performance Engineering - Walbro fuel pumps and more
They note that the data is supplied from Walbro.

 

[Splitpi]

I got the data from Auto Performance Engineering - Walbro fuel pumps and more
They note that the data is supplied from Walbro.

Ahh... different part numbers .... RRE uses GSS-250 for the Wally-190 and APE uses GSS-242

That may explain some of the difference... and how the tests were setup could change values aswell.