Could anyone tell me what I should look for
My sti p reg drops boost at 4000 rpm wht can this be due to?

Cheers

 

Prob a boost leak somewhere!

 

More info needed if you are going to get helpful answers ...

Drops boost from what to what ?

Does it come back ? or just cut at 4000 ish ?

Mods to the car ? What car / year ?

 

Boost kicks in at 3000 rmp drops out 4000-4500
No doesn't come back in
Just cuts out at 4000 ish

I bought the car as I have it here I will list wht it has
It's a 96-97 import wrx sti v3
Ihi vf35 turbo
Walbo fuel pump
Open bell mouth decay
Induction kit
3 inch stainless straight through
5 inch rear box

That's pretty much all I can tell you

Cheers

 

Is the speedo working correctly ?

 

Yes all workin fine

 

Has it got a silicone Turbo inlet pipe?

 

Sorry this maybe a stupid question do please forgive me
Where would this hose be?

Regards

 

In between turbo and MAF under manifold....it is front entry turbo right?

 

Standard pipe

 

Is there some deep and meaningful relationship there?

JohnD

 

Great now today to top this all off I now have a metalic rattle noise coming from which I can only say as the exhaust.. It's a very strange metal rattle but sort of bearin noise

Any ideas
😔

 

Because the OP mentions 4000rpm is when boost drop off, that rpm figure coincides with a faulty speed sensor on the gearbox i.e. when its faulty/fails, the speedo won't rev past 3500-4000rpm (as an OEM inbuilt safety measure)

So rather than a boost fault, it could be a speed sensor fault...?


Well, I think that's what Duncan was angling at...

 

very clever

 

Matt You've got a lot of changes there, the sum of which make it essential that the fuelling and ignition maps be tailored to suit. In an extreme case the mechanical integrity of the engine can be compromised. I certainly hope the rattle is exhaust/heat shield/bracket related and not an internal issue.

JohnD

 

Yup. Would limit it at 4300

As an import it has prob got a kph to mph converter. Thus could be faulty.

 

^^^ Indeed!

 

Could also be coilpacks breaking down - very common failure and you dont describe the symptoms too well. Take them out and remove the rubber cover to check for cracks or falling apart