HFC frontpipe or HFC y-pipe

[Bakkums]

Hello,

 

I'm searching for the best option regarding the exhaust and performance. I think the following options are available:

 

1) Hfc front pipe with open/resonated y-pipe

2) test/resonated test pipes with hfc y-pipe

 

I will need a car with hfc so I can drive the car without having mot problems, on the other hand I want the most performance.

 

My thoughts were hfc front pipe is the best option, because the flow must be equal trough the exhaust from front till back or am I wrong? This has something to do with backpressure on a na tuned car. I've read that a bigger exhaust will perform less at some point.

 

Hope you guys have some good tips and maybe proof of the best option ☺

 

Thanks for al the help.

 

Regards Martijn

Edited January 11, 2017 by Bakkums

[Adrian@TORQEN]

Hi Martijn,

 

Have a look here: https://www.torqen.uk/89-y-pipes

 

Motordyne it's the best bet.

[Jetpilot]

Performance gains will be minimal at best on either so the choice is just down to personal preference.

[Bakkums]

Anybody knows the physics and can tell me what the best option is?

 

Also the exhaust manifold and ypipe back will be changed.

[KyleR]

It can sometimes be tough enough for some to pass mot with 2 HFCs in place of the OEMs, nevermind with a single HFCs in the y-pipe. If your tester is friendly however, just fit whichever.

 

Ps I wonder is there more restriction from a single hfc on the MD y pipe compared to a pair replacing the OEMs?

[Bakkums]

Are there people with the motordyne y-pipe with HFC and had the car on the dyno?

Maybe we can compare these with a dyno chart with HFC front pipes.

 

I've read the motordyne test but they didn't test this I think. Would be a nice input for them and us off course.

[KyleR]

Are there people with the motordyne y-pipe with HFC and had the car on the dyno?

Maybe we can compare these with a dyno chart with HFC front pipes.

 

I've read the motordyne test but they didn't test this I think. Would be a nice input for them and us off course.

 

It would be completely pointless to compare unless it was the same car on the same day with both set ups.

[BobbyZ]

Mark at Abbey Motorsport has said before that they see the best results using the Motordyne XYZ Y-pipe with HFC, and that they should pass MOT if it's up to operating temperature first. Maybe contact him directly to discuss further.

[Bakkums]

Thanks for the input.

I know it isn't a 1 on 1 comparison when it isn't the same car with the same other specs. But it can give an indication.

 

I didn't saw the comment from Mark, but I will contact the tuners directly. Thought it would be nice for the other 350z drivers to know what's the "best" option.

[ZMANALEX]

I see no point in chasing numbers with your proposed set up as the differences will be minimum and I doubt if you will notice any difference when on the bum dyno.

 

Go for what is VOSA friendly and what sounds best.

[Bakkums]

Thanks for all the reactions. Think I'll go for the motordyne HFC with test pipes.

 

Quote:

But here's the kicker. The 2.0" test pipes made 2 more HP than the 2.5" test pipes! ...It left me thinking "COOL. Smaller diameter test pipes make more TQ and more HP. That's a wining combination!"

 

So sombody a long time ago probably misinterpreted the smaller diameter as adding performance by being more restrictive. But this is not the case. It is because of increased scavenging. Smaller diameter pipes near the engine increase the velocity of the shockwave and thereby increasing the effect of scavenging. It was a misinterpretation of the results.

 

So I continued down this line of testing at the Y-pipe primaries. Using the 2.0" test pipes, I then tested various Y-pipe primary diameters. 2.0", 2.25" and 2.5".

 

The expectation was to see similar results... but not quite this time. At least not at the Y-pipe.

 

The 2.0" Y-pipe primaries did indeed provide the highest TQ, but it brought a good portion of the HP down. 2.25" primaries were better but could still be improved upon. The 2.5" Y-pipe primaries provided the best peak power and the best average power.

[KyleR]