R33 Fueling/knock Issues

[Checkbuzz]

Hi Guys

I have recentyl upgraded the RB25DET with 550cc injectors and a HKS GT-RS turbo plus supporting mods. My tuner originally said 245rwkw @ 18psi

At the track for the first time on the weekend and I was getting knock; it started out in 5th gear only, even on small throttle openings and seemed to get worse as the day went on... occuring at lower boost and in lower gears. My tuner came down did some data logging (without a wide band) and reckons my fuel pump isn't keeping up... It is a recently (less then 2 years and 15000kms) installed Walbro 255lph with the direct battery feed (14v) and new earth etc. I went to a lot of trouble to confirm it was a genuine Walbro and was purchased from reputable Aussies dealer (NOT Ebay!)

My tuner also said that they have recently found out that their dyno under-reads by about 30kw at the 250kw mark so my beast is actually putting out more like 275rwkw (nice to have some good news!). I think at this power level the Walbro may be struggling (especially at the end of the straights) and I'm looking at the Deatschwerks DW301 in-tank replacement pump.

Has anyone else experienced similar issues? What was the cause/fix?

My tuner is also recommending a surge tank...

So my main question is how neccessary is a surge tank in an often tracked R33?

It seems like a complicated, expensive set up with more things to go wrong (relying on 2 pumps) and is also very obvious and illegal (car is still street legal and stealthy).

How good are the R33 fuel tanks (baffles) etc for track work? At what point do you seriously need to consider a surge tank on an R33?

Cheers

Edited December 14, 2011 by Checkbuzz

[The Mafia]

I had the exact same problem with my GT3037 and Walboro. You do not need a surge tank. That piece of shit Walboro 342 "255lph" pump, are crap. Once they go beyond 60psi, their flow goes to shit.

Do some maths - 18psi of boost (FPR is 1:1) + 42psi rail pressure + a few psi in pressure drop = 65psi+ of pump pressure needed. If your boost goes a bit higher, or other reasons, the pump needs to make even more pressure.

Once your flow drops off, the car is starving of fuel and leaning out. If you don't do anything about this soon, your engine will blow.

My advice, and I did this - Buy a Nismo 275lph pump, install, and all problems will go away. They are a complete drop in unit, come with the bracket, sock, cables, etc, and it takes about 5 minutes to put them in. Don't buy the bosch 040, their pickup is absolute shit.

If you do want to go cheap, buy a bosch 044 and do a direct replacement of your walboro.

You will most likely need a re-tune too, because if your existing tune was opened right up to accomodate for a failing \ inadequate pump, a new pump will make it as rich as hell. Your tuner should have seen this, instead it looks as if they have gotten lazy, or left it like this so you'll come back to be charged more.

Attached is a picture of the Walboro dying in the ass.

Edited December 14, 2011 by The Mafia

[Levy]

From what my tuner told me is the Walbro 255lph are known to make 500hp atw. Considering it is original, and alot of people on this forum are making over 300rwkw with the same fuel pump. Maybe just bad fuel...

Iv got the same fuel pump myself and also getting installed 555cc injectors and looking at making the same power...il let you know how it goes

[The Mafia]

From what my tuner told me is the Walbro 255lph are known to make 500hp atw. Considering it is original, and alot of people on this forum are making over 300rwkw with the same fuel pump. Maybe just bad fuel...

Iv got the same fuel pump myself and also getting installed 555cc injectors and looking at making the same power...il let you know how it goes

I tuned my own car, and had it connected to the dyno flow tester. If you don't want to listen to me - That's OK, your money not mine. You'll need to change the pump and get a retune, and the retune the tuner will happily charge you $500+ for.

The Graph I have attached states exactly what I said in plain English.

500hp my ass. Anybody that says that the Walboro GSS342 can make that much power is dreaming.

[Levy]

I had the exact same problem with my GT3037 and Walboro. You do not need a surge tank. That piece of shit Walboro 342 "255lph" pump, are crap. Once they go beyond 60psi, their flow goes to shit.

Do some maths - 18psi of boost (FPR is 1:1) + 42psi rail pressure + a few psi in pressure drop = 65psi+ of pump pressure needed. If your boost goes a bit higher, or other reasons, the pump needs to make even more pressure.

Once your flow drops off, the car is starving of fuel and leaning out. If you don't do anything about this soon, your engine will blow.

My advice, and I did this - Buy a Nismo 275lph pump, install, and all problems will go away. They are a complete drop in unit, come with the bracket, sock, cables, etc, and it takes about 5 minutes to put them in. Don't buy the bosch 040, their pickup is absolute shit.

If you do want to go cheap, buy a bosch 044 and do a direct replacement of your walboro.

You will most likely need a re-tune too, because if your existing tune was opened right up to accomodate for a failing \ inadequate pump, a new pump will make it as rich as hell. Your tuner should have seen this, instead it looks as if they have gotten lazy, or left it like this so you'll come back to be charged more.

Attached is a picture of the Walboro dying in the ass.

From what the manufactures say it can easily handle 80psi or more. then again I guess its all theory

[Levy]

I tuned my own car, and had it connected to the dyno flow tester. If you don't want to listen to me - That's OK, your money not mine. You'll need to change the pump and get a retune, and the retune the tuner will happily charge you $500+ for.

The Graph I have attached states exactly what I said in plain English.

500hp my ass. Anybody that says that the Walboro GSS342 can make that much power is dreaming.

500hp does sound like bulshit to me aswell, though im not considering that much power but im sure it can handle 350hp

[DVS JEZ]

How about putting a wideband on it an seeing if its leaning out. Always best to test theories before replacing.

I believe Mafia but like i said best to test it out 1st

[KiwiRS4T]

Tuners round here all want a better fuel pump once you're getting up to 300kw + and I have relegated my Walbro to a lift pump and have a 044 pumping from my surge tank but to be fair I just had a look through the RB25 upgrade thread and there are quite a few people making 300kw with a Walbro.

For the OP I would make sure fuel pressure and afrs are ok on the dyno but would seriously consider a more grunty in-tank pump - the Deatschwerks looks like it will flow enough or a Nismo., Denso etc.

If you are going to the track a lot I would get a surge tank. When you are getting stuck in on the track it is amazing how quickly you can empty your tank, Either that or keep an eagle eye on your fuel levels and keep topping it up. Are surge tanks definitely illegal where youe are? There is no reason for the cops to be looking in your boot anyway.

[SargeRX8]

Tuners round here all want a better fuel pump once you're getting up to 300kw + and I have relegated my Walbro to a lift pump and have a 044 pumping from my surge tank but to be fair I just had a look through the RB25 upgrade thread and there are quite a few people making 300kw with a Walbro.

For the OP I would make sure fuel pressure and afrs are ok on the dyno but would seriously consider a more grunty in-tank pump - the Deatschwerks looks like it will flow enough or a Nismo., Denso etc.

If you are going to the track a lot I would get a surge tank. When you are getting stuck in on the track it is amazing how quickly you can empty your tank, Either that or keep an eagle eye on your fuel levels and keep topping it up. Are surge tanks definitely illegal where youe are? There is no reason for the cops to be looking in your boot anyway.

You drive a Skyline, they have EVERY reason to look in your boot. A uncommon but common thing they look for in the R33 is the battery in the boot. Even though it came like that, they can defect you because it can't vent. If you have a sound system, they can ask to check its not blocking your spare tire. They can even just want to check your spare tire. I don't think surge tanks are legal anywhere. You've made some pretty big mods to the fueling system which if there is a fault could leak fuel and the result could be catastrophic.

Your fuel pump is probably getting too hot and running inefficiently. Get a 040 in tank or if you track often, surge tank might be a good option.

[Checkbuzz]

Bingo!

@65psi the Walbro is only flowing 170lph which is only just enough for 450HP from my (very rough) calculations.

Keep in mind these flow figures for fuel pumps are averages taken from limited samples so you may get a bad one (or a good one)

Anybody trying to run 500HP on one of these is fooling themselves the pump will be right on the edge of it's limits (Walbro only rate them to 500HP and that is only at 3bar)

The NISMO pump seems a little pricey and still only flows 276lph @ 3bar...

The DW301 is half the price and is still flowing close to 275lph @ 5 bar and is also a drop in replacement!

I'll definately be going back in for a tune and will also be recieving a wide-band for Xmas. I am not keen to do any more "testing" (read detonating my engine to hell!) without taking some remedial action first (i.e. new pump) and fitting the wide band so I can see what's going on with my AFRs. For a couple of hundred dollars ia new pump is cheap insurance!

I have seen that engine management warning light flash a little too often for my liking lately... god knows how much damage has already been done

P.S. The PFC is going great thanx Mafia

[Dose Pipe Sutututu]

for that much power you don't need a surge tank, many guys have run just drop in Nismo or Tomei pumps and crank out heaps more power than that and have sexy time with their cars and experience no lean outs like what you're experiencing.

I ran a Tomei drop in fuel pump and made close to 250rwkW on my old R33 and never experience any lean outs, also self tuned.

[DVS JEZ]

Have u got the fuel pump wired up via a relay and battery voltage?

U say the engine light was flashing. What knock did it reach?

Did it max the injector duty?

Did it max the air flow meter?

[SargeRX8]

Is the datasheet for the 040 correct? It say it can flow 300LPH at 94psi and in the same paragraph says its the direct comparable unit to the Wallbro 255.

[boostn0199]

Were you actually experiencing fuel surge on the track? If not then yeah you dont need one. In my case when ever I had anything less then 1/2tank on hairpin turns my car would surge so chucked a surge tank in and no problem now can run til empty if I want. But by the sounds of things your not actually describing experincing fuel surge but just high knock levels.

[Checkbuzz]

I know I don't need a surge tank for the amount of power I'm running - it's the track work that is the concern with surge

for that much power you don't need a surge tank, many guys have run just drop in Nismo or Tomei pumps and crank out heaps more power than that and have sexy time with their cars and experience no lean outs like what you're experiencing.

I ran a Tomei drop in fuel pump and made close to 250rwkW on my old R33 and never experience any lean outs, also self tuned.

[Checkbuzz]

The pump is wired to the battery via a relay and I gave it a new earth etc

Knock was getting up to 120

No (550cc Tomei's should handle this power easy)

No (ditto for the Z32)

My tuner was there at the track (FYI - Sabbadin automotive have fantastic customer service!) pulling timing from cells (5 degrees out of a conservative tune) etc but it just didn't make any difference...

I'm sure they would have double checked injector duty cycle and AFM levels etc the only thing that couldn't be checked was AFRs due to lack of wide-band hence the suspicion about the lack of fuel. The issue was also mostly occuring only in high gears at the end of the straight i.e. after I'd been on WOT for some time again raising suspicions about fuel.

Have u got the fuel pump wired up via a relay and battery voltage?

U say the engine light was flashing. What knock did it reach?

Did it max the injector duty?

Did it max the air flow meter?

[The Mafia]

I will almost guarantee that the fuel pump is running out of flow.

The tuner should not have tuned it like this.

[Checkbuzz]

What data sheet are you looking at Sarge?

There seems to be some wild claims made about the 040 but I tend to go straight to the source: http://apps.bosch.com.au/motorsport/downloads/fuelpumps.pdf

That would be only 102LPH @ 6.5 bar for the 040!!!

A definate downgrade from the Walbro... it's the 044 or nothing from Bosch for me however I have reservations about putting one in the tank (not what they were designed for) which is why I've been looking at the DW301 & Aeromotive 340 (DW301 seems to be more tested and comes from Deatschwerk who are known for quality injectors etc).

FYI - the DW301 has similar flow rate/characteristics as the 040

http://forums.evolutionm.net/automotosports-illinois/566110-bosch-044-aeromotive-stealth-340-deatschwerks-dw300-walbro-255lph-fuel-pump-test.html

Is the datasheet for the 040 correct? It say it can flow 300LPH at 94psi and in the same paragraph says its the direct comparable unit to the Wallbro 255.

[Checkbuzz]

There were no issues on the dyno or during road testing at the time.

I have full confidence in the tuner (Sabbadin automotive) these guys have been doing it longer than most and have an impressive track record.

The problems started happening towards the end of a couple of long spirited runs through the hills and then again on the track deteriorating as the day went on.

It really does sound like the Walbro is getting hot and slowly breaking down under long periods of high load.

Anyone got any experience with the DW301?

I will almost guarantee that the fuel pump is running out of flow.

The tuner should not have tuned it like this.

[The Mafia]

I still don't understand why you'd tune a car right on the edge of the fuel pumps capacity.

Anyone in the industry knows the walboro is shit beyond 60psi, or much beyond stock power.

It's basic maths.