46 replies to this topic

[NickB787]

I want to check the Fuel pressure on the car. I have a brought a gauge only problem is its too short so I cant see it while driving. Will I still get an acurate reading if I extend the hose so its long enough to go into the cabin so I can keep an eye on it?

[vocky]

yes, but please remember it's fuel under high pressure inside the cabin, so make sure it's secure 

[NickB787]

Thanks , will do

[techieboy]

What was the thread size/shape/details for the bleed valve on the high pressure line Nick?

[NickB787]

Believe it or not I would say it's a truck tyre valve. I will nip over to Formula one and see if they have anything to help me, need a new dust cap anyway.

 

 

[Exmantaa]

What is your base pressure now?  (so with disconnected vacuum line)

[NickB787]

I showed approx 4.15-4.2 idle hose disconnected bit high really

 

I have a spare I borrowed from Lee may swap it just to check

 

Peter is saying

3.3 idle (0.5 Bar)

3.8 engine off

6.0 under full load 6500 rpm (2.2 bar)

Edited by NickB777, 23 September 2013 - 09:59 AM.

[Exmantaa]

3.3 idle (0.5 Bar) => Depends on idle rpm and f.i. cams. Normally substract ~0.6 bar from Base pressure.

3.8 engine off.

6.0 under full load 6500 rpm (2.2 bar) => Depends on boost pressure. Harrop on full swing and decent exhaust flow reaches close to 1.5 bar, so you should see ~5.3 bar fuel pressure if your system can cope with the fuel flow. (2.2 is A LOT of boost...)

 

 

Edited by Exmantaa, 23 September 2013 - 03:07 PM.

[NickB787]

Just been out couldn't get a direct fitment for the gauge, did get some proper hose though so will get some hose connectors and will cut the pipework and add about a mtr of pipework to allow me to see it properly.

 

am running a 2.8 when sorted will drop it to 2.7 pulley so should run 1.8 bar if I can keep the temps down, may have to turn the water injecton on

 

IAT are about 45C when boosting it now much better. 

 

 

Edited by NickB777, 23 September 2013 - 04:13 PM.

[Exmantaa]

Just been out couldn't get a direct fitment for the gauge, did get some proper hose though so will get some hose connectors and will cut the pipework and add about a mtr of pipework to allow me to see it properly.

 

am running a 2.8 when sorted will drop it to 2.7 pulley so should run 1.8 bar if I can keep the temps down, may have to turn the water injecton on

 

IAT are about 45C when boosting it now much better. 

 

 

 

  Did you ever check your intake temperatures on serious use??

 

I know the track temps with a 3.15" Harrop pulley, and no way we're going down before the water injection cools things down to more acceptable levels... 

[NickB787]

These have just been a few runs I have not yet given it some constant beans until I have the fuelling sorted and mapped properly.

[Exmantaa]

Tip; start easy on the pulley, as our 3.15 reached almost 90*C on the track... (1.48 bar boost or so)

 

With a smaller pulley you get diminishing returns (drive loss & heat) and even some US guys now say that a 2.9 on the Harrop is about the smallest you should use... 

[NickB787]

I extended the hose so I can now check the pressure in the cabin while driving.

 

Something strange though, I changed the FPR for a spare and still get 4.2 bar on idle, how does CMS mode the FPR? do they do mod the fuel rail or the FPR itself? 

 

Might need to nip over to someone with a vx so I can check to see if it is the gauge

Edited by NickB777, 26 September 2013 - 11:25 AM.

[siztenboots]

crushing the FPR means it opens at a higher pressure

[Nev]

Are you saying that your harrop can make 2.2 Bar of boost in the inlet manifold? That seems mega high to me Nick, AITs will be mental with prolonged use.  You are certainly wise to lower the boost of 1.8 Bar (or perhaps even lower).

 

Did you ever install a meth/water spray kit BTW ? If so, what results did it produce please?

 

Edited by Nev, 26 September 2013 - 11:34 AM.

[NickB787]

crushing the FPR means it opens at a higher pressure

I know they use a hammer on it somewhere but is it the bit you can remove or do they something within the rail itself, wonder since I have change the actual FPR itself twice now

Edited by NickB777, 26 September 2013 - 11:34 AM.

[Nev]

 

crushing the FPR means it opens at a higher pressure

I know they use a hammer on it somewhere but is it the bit you can remove or do they something within the rail itself, wonder since I have change the actual FPR itself twice now

 

 

You need to get some sort of flat ended and round shaped punch/tool, like a length of iron bar - perhaps 8mm diameter. Place that on the top of the FPR and then whack it with a hammer. This depresses the metal top of the FPR down a bit, thus exerting more pressure on the diaphragm inside.

 

All rather "vauge" what extra pressure you will get, and once crushed too much, you can't uncrush it to reduce the pressure.

 

Bosch do sell the same form factor FPRs up to about 5 Bar, but they are expensive.

Edited by Nev, 26 September 2013 - 11:38 AM.

[techieboy]

Can't see what they could possibly do to the rail. Given the added complexity of your fuel system, I'm not even sure a comparison to my fuel system would be of much use.

[NickB787]

Was just wondering if I attach the fuel pressure gauge to yours to see your shows 3.4 or 4.2

 

I have one of those adjustable ones which I bought (  spelling) some time ago (same as Lee has but removed)

wonder if I should try that or are they rubbish

Edited by NickB777, 26 September 2013 - 11:44 AM.

[The Batman]

 

crushing the FPR means it opens at a higher pressure

I know they use a hammer on it somewhere but is it the bit you can remove or do they something within the rail itself, wonder since I have change the actual FPR itself twice now  

  You need to get some sort of flat ended and round shaped punch/tool, like a length of iron bar - perhaps 8mm diameter. Place that on the top of the FPR and then whack it with a hammer. This depresses the metal top of the FPR down a bit, thus exerting more pressure on the diaphragm inside.   All rather "vauge" what extra pressure you will get, and once crushed too much, you can't uncrush it to reduce the pressure.   Bosch do sell the same form factor FPRs up to about 5 Bar, but they are expensive.

Use a socket, vice and hammer