My Datalog

[VAROOM]

Hi Jez,

i just emailed you my datalog hope you get it ok.

can you please reply to me on this forum as i sent you the email from my work computer.

cheers dude.

[Jez]

I've had a look at the logs

It seems like air flow is tailing off a lot as you approach 6krpm. This could be a number of things:
The hose between the turbo and AFM collapsing
Some sort of exhaust restriction
Valve problems

Check the hose should be easy, and if you're on a free flow exhaust I doubt its that...

[VAROOM]

Hey,

cheers for looking at the datalog for me.

the intake hose from airflow meter to turbo has been replaced with a stainless pipe with silicone ends.....its is slightly shorter than the rubber one not much but maybe a couple of inches?

i have tubular manifold,3" elbo,d/pipe,de-cats,mongoose system and blitz nur back box...the blitz has started rattling but i can see right through the baffles in the back box so it doesnt look restricted?

as for valves i spoke to the engine shop guy and he said they were re-cut when the head was skimmed and pressure tested so they should be ok.

could it be something to do with the variable cam? ive fitted a new sprocket and solenoid but dont really know if it is working or not...is there a way i can test this?

:cry:

[VAROOM]

Ive sent you a 2nd datalog as i got a better chance today to hold it at full throttle.

[VAROOM]

found out on the way home tonight that car behaves like this...

0.9 bar boost car will rev to 7.5k no problem
1.0 bar boost car will rev to 7k max
1.1 bar boost car will rev to 6.5k max
1.2 bar boost car will rev to 6k max

i am using the standard turbo with 110k miles on it do you reckon its the problem?

[Karan]

it shouldstill carry on at lower boost really shouldnt it til 7.5k

mine did something similar when my rubber hose was collapsing, but it felt slower up to that point too......

[VAROOM]

yeah im running out of ideas now..this weekend i fitted another fuel pump..another cas....replaced all inlet manifold gaskets...my intake hose is metal.

none of this has made a difference.

this weekend im going back to the standard exhaust manifold to see if this makes any difference.

[Jez]

:(
Really hope you find the prob - I'm out of ideas...

[Gary@APT]

its weak valve springs try some stronger ones

[Jez]

its weak valve springs try some stronger ones

Thats what I initially thought - just a ball ache to change - lol!
Varoom - I've got them in stock, if you want to get them fitted

[VAROOM]

Thats what I initially thought - just a ball ache to change - lol!
Varoom - I've got them in stock, if you want to get them fitted

Kool...how much?

can i fit them without removing my head?

ive just replaced my headgasket with a cometic one and had my valves re-cut/ground and new valve stem seals fitted.....so i really dont want to be removing the head again.

ive ordered a snap-on cylinder leak-down tester so this will fill the cylinders with air.

what do i need to compress the valve springs?

im pretty good with car electrics but im no engine builder

this weak valve spring theory makes total sense....oooh maybe im gona get it sorred after all...im getting excited its been a longtime scince ive had fun in my car!!!

cheers

[Jez]

If you've got the leak down tester then you're halfway there. You just need a valve spring compressor.

You then bring the piston to top dead centre, pressurise the cylinder to keep the valves in place and then remove the spring.

Ive never done it, but it can be done without removing the head.

Let me know if you'd like some springs - they're Tomei uprated springs and £189.99 :)