symptoms of faulty N75

[bentaw]

When i am on the motorway or going up the slip road in say 5th or 6 th and i put my foot down it feels like the car is going on full boost almost like it gets to a certain PSI and holds, whereas when i am in lower gears the car seems to come on boost and not stop it doesnt happen all the time only sometimes. It also at some points hits a brick wall at some point in the rev range i am accelerating and like a judder its like the turbo has gone and then it kicks ack in again but a lot slower than normal.

Is this symptoms of a faulty N75 or something else

 

[Mitchy]

Have you got a boost gauge bentaw?

Surely a neccessity for a chipped car? Mines has been so useful at detecting problems that if i didnt have 1 i'd be chasing my arse all day trying to find out what was wrong

Im not really understanding what your problem is? When in 5th and 6th gear, it hits a certain psi and doesnt go further? But when in 1st-4th it goes past that ''certain psi'' to a higher pressure?

Brick wall could be down to your revo map, pulling timing if it has advanced too far.

You really need to go stage 2 as quick as you can with your additional mods as you may be hitting a brick wall due to too much ignition advance.

Do you have an SPS dongle to adjust timing?

 

[bentaw]

yeah that is what it feels like, i will give you the scenario i am on the motorway in 6th dong 70mph at 3000rpm to overtake the car in front i pull out and put my foot down in the same gear and it seems slow to react and sounds like it is really struggling but then slowly but surely it starts to move. It is probably normal and me just be silly but if i was on a dual carrageway and did that in 3rd or even 4th to an extent it seems to pull more at the same rpm. Its probably the way the gears are setup and me just being thick

 

[bentaw]

no dont have a boost gauge, it feels in 1-4 it goes to 1.55bar and in 5th and 6th it only goes to 1.2bar when under load

 

[Mitchy]

Is your clutch slipping at all, as i had similar symptoms in 5th/6th gear at exactly the same 3000rpm although it was fairly obvious as my revs would rise too quick for the speedo and then settle down once the clutch had engaged properly

Boost gauges are so useful at detecting problems! You would be able to definitely tell if you are hitting required pressure.

If it were N75 surely it would happen in all gears not just 5th/6th?

What happens if you plant the foot at say 4000rpm in 5th/6th gear? Is it okay then?

 

[bentaw]

no clutch slip and i will give it a go later let you know

 

[Scotty_b]

Sounds like turbo lag to me? AS my turbos not up to pressure at those speeds so takes a while to get spun up comprade to lower gear pulls as shes already blowing away

 

[bentaw]

it probably is that mate and its just me being paranoid

 

[Mitchy]

Yes if it pulls fine at 4000rpm then i agree with scotty its probably just turbo lag!

As to hitting a brick wall, thats got to be with your mapping. Ecu pulling back

 

[bentaw]

how is your motor going now scotty whats the latet spec for it and what plans do you have for it

 

[bentaw]

yeah but it doesnt do it all the time, if it did it all the time i could understand it pulling back ike that

 

[Pabs]

Ben, I'd say its normal - and its turbo lag. My car does the same - lower gears probably have more torque too, so that'll make a difference.

I'd not worry about it mate, but i'd consider a boost gauge.

Hows your overheating problem going? Has your car done it since we last spoke? Mine has

 

[bentaw]

funnily enough mate mine hasnt dont know why perhaps its cos i have been treating her recently what with 99ron fuel, cleaning her and sorting her boost issues out but who knows its a weird one but i dont think it is down to the weather either cos it did it to me in the winter last year i dont know what is wrong. Has yours ever gone to the point of 120 degrees cos mine never makes it that high which is weird it only rises to about 100/105

As regards to the lag i think that is what it is, booted at 4000rpm in 5th and it pulled like it should so thanks for putting my mind at rest guys

 

[Pabs]

mate, mine's never hit 120 either, and thats the warning light/buzzer temp too.
I only hit 100, maybe 105 and then it drops rapidly back down to 90.

I've sorted my boost issues and stuff too now, so all is peachy

 

[Mitchy]

Is this only a problem with the pace FMIC? Pabs have you got 1 aswell?

 

[Pabs]

no my friend - I have a Forge FMIC. Its a really weird problem. I think we've both replaced thermostats too. I know I've done the waterpump/coolant and everything recently too at my 60k service.

I'm due my 70k service in a few weeks, but thats just oil and filters i think.

 

[bentaw]

i have not replaced the thermostat yet and i havnt done the water pump yet fingers crossed i wont have too till the cam belt service, but it is a weird problem

 

[Pabs]

well i stand corrected. But my thermostat was fine on removal, so didnt need to change it.