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stock fuel system for single turbo and intercooler/downpipe flow ?


msupra1

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I have a few questions that I'm looking to get some insight on, so just making one thread for this.

 

My J-spec 6-speed is getting new GSC S1 269 cams put in along with AEM water/meth kit, I have the parts ready to go in.

Current setup is AEM V2, borg warner s366 turbo, sard 800cc drop-in injectors, walbro 400lph pump, hks 3.75" carbon exhaust and 3" downpipe.

 

After the new cams and depending on my boost level, I'm aiming for 580-600whp.

Dyno's here read In WHP, so +15% that should be around 660-690bhp I think.

 

 

So my questions are,

 

- I'm running stock fuel lines and stock fuel rail. I have drop-in Sard 800cc Injectors, along with Walbro 400lph pump with 14v wire mod.

My performance shop told me my system as it sits should suffice for my power goals. And I know the Injectors and pump should be fine,

I'm just trying to see what the true limit of the lines/rail? I'd like to avoid touching it unless necessary.

 

- I have an ARC 2 row intercooler and not sure if there would be significant power gains going to a 3 row setup. Would mine be fine for my power goals?

 

- The downpipe is 3" that goes down to an HKS Carbon 3.75" exhaust. Would there really be any point going to a 4" for that power? I'd rather avoid doing that but just something to consider.

 

 

Tuning is not cheap, so I want to make sure my setup is good before I have that done.

 

Cheers

Edited by msupra1 (see edit history)
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A cheap multimeter that has a K type temp sensor input, and a type K wire thermocouple trapped under the hose to the throttle body will let you monitor inlet air temps. Or maybe your ecu will log them from the stock air temp thermocouple? Then you can actually see in real time how your current IC is coping. Most issues with front mount intercoolers is a lot of the core is totally wasted and the bumper aperture masks it, as it's the wrong shape, and that they are rarely ducted, and air WILL bypass the core rather than force through it, given a chance. The importance of ducting to air to air or air fluid heat interchangers CANNOT be stressed enough, yet is usually overlooked as it can be very tricky to implement. The small looking stock side mount intercooler is so good just because of this. It is fully ducted from a high pressure area, with a correct angle diffuser section, and exits into a low pressure area (the front wheel well).

 

 

As for your fuel system a pressure gauge and AFR readings will tell you if it's marginal. I think folk get carried away with fancy rails, centre fed rails, huge fuel lines, blah blah. Bit of a marketing thing, the stock lines, regulator and rail would probably suffice for 90% of builds assuming suitable injectors are available..

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Dont get so hung up on numbers if your worried about the cost,

 

There are big gains to have from a 4" down pipe as well as many other things but come as at a cost which you are worried about , So get the car mapped drive it and see if you like it then change if your not happy with it ,

 

http://www.mkiv.co.uk/vbb/showthread.php?278633-3-quot-vs-3-5-quot-exhaust-confirmed-results&highlight=results

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Good to know ^

I was reading about lots of guys doing big numbers on 3".

 

This current downpipe I have now is my 3rd I've had fabricated, which involved welding a new flange size to the turbo.

So another reason why it's just easier to keep things as is, unless necessary.

 

I think I'm going to leave my setup as is, put the cams and meth injection kit in and get it tuned. When I get around the 660-690bhp range +/- it will suffice for my goals with this car.

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Guest Budz86

You're probably gonna want and FPR, but everything else you mentioned in your first post should be fine for that power. Only thing to consider is the ducting for the FMIC as Chris says :)

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I'll have to go do some more research about them. What is involved to install one?

Adjusting the FPR just increases the injector flow = resulting in more power?

 

I guess what I'm trying to figure out if the injector flow is left at the standard setting if that would suffice for my power. I guess it's hard to tell.

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You're probably gonna want and FPR, but everything else you mentioned in your first post should be fine for that power. Only thing to consider is the ducting for the FMIC as Chris says :)

 

Luckly I have a Ridox front end which really exposes the intercooler

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Can stock lines take ethanol?

You would proberbly want a fpr.

 

I'm not too sure,

 

I am running Pump Gas + 50/50 methonal/water mix. Which from my understanding is fine, and that's injected directly into the motor through intake manifold

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I'll have to go do some more research about them. What is involved to install one?

Adjusting the FPR just increases the injector flow = resulting in more power?

 

I guess what I'm trying to figure out if the injector flow is left at the standard setting if that would suffice for my power. I guess it's hard to tell.

 

 

Fuel pressure against the injectors is governed by the line pressure, which is controlled by the FPR. The FPR pressure is skewed by the vacuum / pressure line to it from the intake plenum. Under vacuum the fuel pressure is reduced, under boost it's increased, by the boost or vacuum on a 1 to 1 basis. The injectors are then controlled by the ECU to open and close both at the right time, and for how long, adding finer control to how much fuel is delivered. Everything should work together, and it's quite complex. More fuel pressure or more fuel flow does not always equal more power, it is much more subtle than that. More fuel pressure or flow, (and they are different things), could well give less power.

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