Thread: 4-1 vs. 4-2-1 dyno comparison

Header Dyno Comparison: 4-1 Nismo v 4-2-1 AEBS With Dyno Charts - MySpecV Archive

Originally Posted by smokinjoe

Just got back and the results where rather impressive. As I said, I tried to make this as close to an actual header v header as possible. The dyno was done on a Mustang dyno which typically reads about 15% less than a Dyno Jet. The tuning was done first on the Nismo header and then 30 mins later (after the swap) we redyno'd the car with the DC style header. Both have very similar 2.5" custom mid pipes with no cat.

First I would like to thank the great folks - Derrick and Dave - at Lethal Injection. If you are close to Atlanta, check them out. They have an in house machine shop and have completed some b16 crank/rod swaps into B15s with great success. Cool bunch of guys. It took us about 3 hrs to get this wrapped up and they were very cool about all of it.

Here are both headers:



And here is the DC Style with the custom mid pipe:






And my track car Spec:










OK - first, tuning the SAFC with the Nismo header. We tuned the AFR to 13.2 across the board then dropped it to high 12s past 5400 rpm b/c we noticed only a difference of 1hp/1tq. And I drive @ WOT all the time, a little richer was safer. The dip in the AFR on the untuned @ 4300 was the LM1 freaking out for a split sec. We later swapped it out for a newer one.

The car only picked up 2wtq and 4whp tuned. For a peak of 163wtq / 152whp or 187wtq / 175whp per a Dyno Jet (estimated). Thats est. 224.9 crank tq and 210 crank hp.




Then we installed the DC style header and custom mid pipe:




And the results....?? not so great. The car lost 6wtq and 4whp.. everywhere. It didnt perform like anyone thought it would. Maybe it has too little backpressure and not enough scavenging. I dunno. The car sounded different - not as fast and quieter. I thought I would see some gains somewhere. Nope. We ran the dyno again and repeated the results.

Here is the tuned Nismo v the DC/AEBS style. The Nismo is the dotted line. We even raised the AFRs on the DC header to 13 across the board. Nothing.





And to make matters worse, the DC/AEBS makes less power than the untuned Nismo. The untuned Nismo (our baseline) is the dotted line.




So there you go. Not a ton of power from a SAFC (on my race car) and not much better for a 4-2-1 v the Nismo.


+1 Nismo

Those of you with a stock header/mid pipe - the custom DC unit in the pictures will be up for sale. Its better than stock

The modification done to the 4-2-1 header:

Originally Posted by smokinjoe

I did exactly as suggested and made a custom 2.5" midpipe (I'll post pictures) with my 4-2-1 header. I suggest everyone do this. Look what I found where the 2 goes into 1. The piping is 2 1/4, but with this restriction, it drops to 1.5. I cant believe this crap. I have a dyno session scheduled for Thur to compare the Nismo to the 4-2-1. It will be apples to apples since the mid pipes are both 2.5" similar custom designs. No cats. So its truly the header that will show a difference.

That's pretty interesting.

wow

That's very interesting. I was expecting the shape of the torque curve to change, if not the maximum value. But they both seemed to make peak torque at about the same RPM.

I really want to see the before/after dyno of the Megan 4-1 on that other thread. I read somewhere that all of the 4-1 headers have about a 0.5 WHP difference between them, but there was no dyno sheet to back that statement up.

I noticed that the layout of the Megan primaries is similar to the layout of the DC primaries (much more compact though), which is different from all the other 4-1s I've seen.

I have the Megan 4-1 and Megan downpipe I feel a big difference in my topend

Sent from my iPhone using Tapatalk

Originally Posted by servspec04

I have the Megan 4-1 and Megan downpipe I feel a big difference in my topend

Sent from my iPhone using Tapatalk

I have the Megan 4-1 too, and I did gain some top end. I've read the number is around 12 WHP at redline (no dyno).

It's probably safe to say that any header will perform better than stock; I'm just being an enginerd about it, haha.

nevermind

I hate to say i told you so, but...





Wheres pimpsmurf talkin about my butt dynos??????

No other thread/investigation has proved anything till now.

This is what I was asking for ALL ALONG.

Looks like I'll be in the market for a new header...

well apparently AEBS was 4-2-1. my mistake!



and this is pretty hilarious. this is the 2-1 section of the cheap ass ebay 4-2-1 headers.

^^^ WOW holy shit WTF they really put that shit out on the market?! ebay SMH

I rest my fucking case.

I can't stand those morons that argue with me "what is the big deal with an eBay header. Metal is metal." Well what now, assholes?

Originally Posted by QR25DE_SpecV

I rest my fucking case.

I can't stand those morons that argue with me "what is the big deal with an eBay header. Metal is metal." Well what now, assholes?

i cant even say anything. ive been the guy in that quote about ebay parts such as intercoolers. just wow

There is only one company that makes decent eBay cores. I forget who they are.

So what are the names of some 2.5" 4-1 Headers? Isn't the Megan header 2.25"?

Originally Posted by QR25DE_SpecV

There is only one company that makes decent eBay cores. I forget who they are.

So what are the names of some 2.5" 4-1 Headers? Isn't the Megan header 2.25"?

XS claims to be 2.5", although idk how true that is.. it does look to be the same as my midpipe and catback which are 2.5.. i dont think they make headers for the QR aymore though

Originally Posted by 04specvnj

XS claims to be 2.5", although idk how true that is.. it does look to be the same as my midpipe and catback which are 2.5.. i dont think they make headers for the QR aymore though

I don't want a fucking XS anyway. Worthless hunks of shit.

Originally Posted by QR25DE_SpecV

I don't want a fucking XS anyway. Worthless hunks of shit.

i doubt it. what info do you have to back that up? the price is low?

No, the fact that I've had to help my buddy remove his multiple times and send it back, because the flex sections/welds are absolute shit.

That, in conjunction with other peoples complaints that I hear so much about. Don't ask me to provide proof. Find it.

Originally Posted by QR25DE_SpecV

No, the fact that I've had to help my buddy remove his multiple times and send it back, because the flex sections/welds are absolute shit.

That, in conjunction with other peoples complaints that I hear so much about. Don't ask me to provide proof. Find it.

well i wouldnt even begin to argue the flex section was garbage, i had to replace it in less than a month. other than that ive had it over a year, for about 30k and its a sick header. i have my own proof, i dont have to find anything

Originally Posted by 04specvnj

well i wouldnt even begin to argue the flex section was garbage, i had to replace it in less than a month. other than that ive had it over a year, for about 30k and its a sick header. i have my own proof, i dont have to find anything

Glad to hear it.