Mmh interesting I was looking to replace the original with the autodelta intake pipe,not so sure now, I run on super aswell

 

might make a difference if you have it tuned with the pipe installed....

 

He makes a valid point Joe

 

If the boxes are just there to keep the noise down then why should it be tuned with the pipe installed? Do autodelta sell it with a remap? Nope.

Anyway make what you want of the info, just giving you the facts.

 

Is it possible that the timing might be ever so slightly out? Would that explain your missing power?

 

My timings fine it hasn't been changed since the 261bhp figure.

 

The helmholtz resonators do more than stifle noise.

The chamber also smooths out the tiny surges and hollows in airflow caused by the opening and closing of valves. It's effect is only noticed at small throttle openings.

I have a single 90degree aluminium 89mm pipe installed. So I lose 1 bend.

 

Joe

Are you suggesting that Jano does not know what he is doing ?

John

 

But it was mapped on 95 fuel? Surely it will perform best on the fuel the map was based on? I.e my noble is mapped to 497 bhp on 98Ron but if I run it on 95 it will run fine but will only make about 450

 

And seeing that it was 11 bhp down from before would suggest their rolling road was telling porkies

John

 

They always are :lol:the only true figure is an engine dyno, sealed room. Rolling roads can read whatever you punch into them. Good for pub talk.as long as it feels better than standard, it's worth the money

 

My car has had the same calculations each dyno run. I loaded them myself. Regarding the fuel mapping I need to talk to Augusto from red dot.. He wasn't there this week.

 

How is / was the power being measured on the rolling road? 3rd, 4th or 5th gear. Weather on the day the intake was fitted and the day it wasn't? Too many variables with dynos, even the same ones. Probably nothing to worry about. Bet it sounds better than standard which is the main reason for one.

 

All on the same day. Power measured through the tyres on an American land and sea dyno...Not sure which gear, third or fourth I think.

I'm just putting the results up. I don't care if the pipe is any good or not. Most people won't tell the difference on the road.

 

Best change your avatar then.

 

Joe. Another quick question.
1.Have you had the timing belt changed inbetween this? If so could it have been done with 3.0 locks as this could also account for your power loss.
2.Another point. Did you use the same dyno both times?

Just thinking of possible reasons. Jano was a smart man and I'd like to think the pipe was ok. Mainly because I have one :lol:

 

Timing is exactly the same Joss. I had the belts done in June last year when I bought the car.

Same dyno and same calibrations. There is a specific file for each car model and engine.

I had a 156 GTA back in 2008 that a certain dealer in Cheshire did the belts with 3.0 cam locks.

 

Out of ideas then. Surely with the old pipe off it should have gone back to 261. You say it leans out so perhaps look at the MAF

 

Rolling roads are a dark art. The temp, humidity, adaption on the ECU on the day. They all change outputs.

The only useful info is direct before and after comparisons for the car in question.

On this car, the AD pipe reduces peak power. That's all.

If the car didn't need the resonators. It wouldn't have them.

That said I removed mine for an alloy pipe. Didn't notice any difference in drivability or power, but a tiny improvement in mpg so it's staying.

 

To be honest the pipe looks fantastic. Really finishes off the engine bay. As has been said before though, companies like Alfa don't spend thousands on research for nothing.

I'm doing the CF2 pipes very soon though. We all know that that is something Alfa had to do purely for emissions...

 

I wouldn't worry about the dyno result. Go back tomorrow and you'll probably get another figure. They are what they are, just a number on the day. If it was over 261, you'd be made up!

 

I was expecting it to be over 261 on the basis of using V-power religiously for 3 months.

 

V Power is only 98 octane when it is made, after that it decays quickly. If the car isn't filled with freshly delivered VPower, any power increase for higher octane will be limited.

Regular 95 suffers the same. I remember reading that 6 month old fuel can have an octane rating as low as 80 or 85 just from sitting in your tank.

 

I disagree with the view that super unleaded doesn't do much. When they do the fuel tests V Power regularly comes out on top both in terms of power made and mpg, usually followed by Tesco 99 with the regular supermarket unleaded coming in bottom.

 

Agreed, but from the research I have done though it seems it has a much bigger effect on the turbo or supercharged engines. The 5th gear test showed only a couple of bhp on the golf gti they tested.

@ Andy, V-power is 99 octane here in the UK.

@ torker - yes I know that there are a lot of variables. Probably 2-3BHP tolerance on each run but still if my figure has dropped off 18BHP there is definitely an issue but the torque figures can't really lie if the car gains 10ft lb of torque after changing a simple pipe.

 

Fresh high octane fuel has an effect, as I found a few weeks back, the problem is it's life expectancy. Most GTAs are used for low mileage per year. A tank of. 60 odd litres will last maybe a month. High octane fuel will work at its peak for the first week, and will be down to 95 octane rating by week 4. It's only really good for high mileage people who use a lot, fast.

That said the detergent and cleansing agents are stable and continue to be effective . It's the octane increasing additives that don't last well.

 

I may have to eat my words.

Just found this

http://www.bp.com/retail/liveassets...ia/STAGING/local_assets/downloads_pdfs/0_999/Petrol_Life_in_vehicle_tanksv4.pdf

From BP which suggests that although light volatile elements in petrol evaporate off- the octane rating INCREASES over time. That means less fuel, but higher power, although harder starting due to less high volatility elements.

 

Is the diameter of AD intake pipe bigger than stock? If so, the reason could be lowered airflow speed and thus negative impact on the cylinder filling volumetric efficiency. The airflow log during the dynotest would prove it.

 

It's around the same as stock. A bit flatter at one point. The inside of the pipe was not smooth though, far from it in fact.

 

The inside shouldn't be smooth. Intake pipe inside surfaces should be roughened to a degree so air doesn't stick and separate creating lumpy flow. Same reason a golf ball has dimples.

 

yep, the microturbulences. But I'm unsure if this apply to any roughness. The golf ball dimples are very special.
Although the turbulences at golf ball dimples are used to lower the pressure on the ball upstream face. So talking about pipe, it would benefit it only in the outer side of the bend I'd say.

 

This is a very interesting experiment Joe!! I should be at Reddot for the RR day as I have no idea what mine is running these days :lol: