Alfa Romeo Forum banner

1 - 5 of 5 Posts
S

·
Guest
Joined
·
0 Posts
Discussion Starter #1 (Edited)
Today I conducted a massively un-scientific experiment.

My car came with the big black plastic resonator. I replaced it about a year and a half ago with a 90mm alloy elbow.

Recent talk here about the relative merits of having the resonator or not got me thinking.

Today, I took the car with the alloy elbow for a drive. I used a 2ish mile stretch of single carriageway including a number of bendy bits.

I set a time along the route, never exceeding 60 mph as I wanted to measure acceleration, not top speed. I did this 3 times. With 1 aborted go due to traffic (otherwise I had it all to myself.) the three decent runs were an average of 2minutes and 35seconds.

I then removed the alloy elbow and put the resonator bit back on. I tools 20 minute drive to allow the car to resort itself.

I did the 3 runs again. Averaged out at 2 mins 29.

Therefore, utterly un-scientifically, the resonator does add speed on acceleration.

Overall feel however isn't as pleasant. The induction roar is now much muted, the added kick at 4500rpm ish is much less marked, and the overall excitement is less to. It seems the resonator adds torque, but like a Diesel engine, it destroys enjoyment.

I'll keep the resonator pipe on for now, and repeat the process in reverse on a few weeks to see if the engine adaptation to the change makes a difference.
 

·
Registered
Joined
·
198 Posts
Nice work :thumbs: Maybe a more accurate method would be runs in a single gear, like, 10-60mph in second, repeat repeat repeat, maybe use multiecuscan to log the speed against time.

I remember a while ago somebody posted dyno graphs with and without the intake resonator, and it did lose power, about 1-2hp around the mid-high rpm range. That's less than 1%, I didn't really notice any change. Apart from the nice sound that is :)
 

·
Registered
Joined
·
2,654 Posts
I'll pitch in on this again with the same stance as last time.. mine was much more choked when dropping a gear and flooring it at motorway speeds once I lost the resonator.. the resonator seems to gives the engine a pocket of air to tap into immediately when flooring it, rather than without, where there is more of a delay pulling it through.. just a guess, and as unscientific as your own experiments.. ! It's almost like the concept of having the small turbo on the BMW's twin turbo.. for an immediate throttle response.. maybe? :) It still sounds nice if you take the snorkel off.. then you have the best of both
 

·
Premium Member
Joined
·
19,119 Posts
What you haven't taken into account andy is the change in air temp :lol: mate it's a pointless test as you say. I seem to remember the autodelta carbon pipe gave 1/2 a torque less low down and a couple of bhp up top. Basically it's absolutely no different. It's all about the extra noise.
 
S

·
Guest
Joined
·
0 Posts
Discussion Starter #5 (Edited)
Yeah, it's no big thing. I'm not too fussed about it all.

The day to day drive is better with the resonator fitted though. It feels more eager to go from low down. The lose of noise and s degree of the 'on cam' kick are the downsides.

I'll leave it as is for the time being because the chrome pipe needs the rubber MAF connector to be stretched a lot to fit. It needs time and washing up liquid. The resonator refit was 5 minutes, most of which was finding the 7mm socket for the clips.

On temperature difference, the difference was barely anything. The swap took only a few minutes. Only benefit on the second set of runs was a slightly emptier fuel tank.
 
1 - 5 of 5 Posts
Top