I've got a biggish turbo for my new 2.0 engine and my mapper say it's going to be laggy on a 2.0 and says I should get a narrower up pipe to help spool and bring full boost down by a couple of hundred rpm.

That's all great but how does that work? Is it the same principle as putting your finger over the end of a hose pipe?

 

at a guess its gonna be higher pressure gas entering, but iam from far an expert

 

The exhaust gases will flow faster as the pipe gets norrower i think.

 

At low flow rates a narrowing ( venturi ) causes the gas velocity to increase.
To turn the turbine wheel it's a product of the mass of gas multiplied by it's speed ( momentum).

At higher flow rates the slight restriction is not an issue as most turbos can produce loads more boost than the engine can withstand.

All IMHO.

dunx

 

I was wondering how much difference it would really make and how effective it was, has anyone used one?

Thanks

 

I used to have RCM headers & up pipe ... replaced the up-pipe with one of Harveys which did make a difference. I have rr results somewhere before & after which I'll attempt to post up. Harveys pipe starts the same width as the RCM one but narrows to help spool up.

TX.

Edit - the after is 1bar at 4000rpm, 1.8bar at 4600rpm. The before is 1bar at 4100rpm, 1.7bar at 4600rpm. Both runs at same dyno. Small win I guess! The car "feels" much better though, well worth it for a modest outlay imho.

 

Sounds interesting, it'd be interesting to see the graphs for comparison.

What does Harvey's up pipe cost?

 

Think it's £149 wrapped. Might even incl install if you get Harvey to do it.

Just trying to find old graph now.

TX.

 

Thanks Won't be getting Harvey to fit it because we'll fit it when we build the engine.

 

3 bolt uppipe, DEI heatwrapped with five new Subaru studs specifically designed for the GT 2 spec type headers (tubular) £149.
2 bolt uppipe for use with standard headers or ported headers, DEI heat wrapped with five new Subaru studs £139.

 

Thanks Harvey When Rich is on the mend I'll be in touch Can't do a lot with the bits I have until he's fixed

Get well soon Rich

 

Pass my regards on. I did not know he was out of commission.

 

yes exactly the same except you dont get wet

 

...........although I do believe the principal was worked out by a guy dunking pipes of various sizes in the river Seine

Shaun

 

Will do He broke his foot in a motorbike accident last week