JFR Equal Length Y-Pipe for 2nd Gen Tacoma, T4R, & FJ Cruisers

Appreciate the quick reply, I read the OP but he didn't go into details of where the deficiencies were other than that scavenging was not maximized.
What does that translate to? Quantified how? Where are additional gains at? Low end? high end? across the board?
While power can be technically gained, is it everyday usable power? or just power at WOT close to redline?
A comparison to stock and or the URD would be helpful to give me a base line.

 

The easiest way, since no dynos have been done,that I can remember, is to compare MAF flow changes. As well as before and after datalogs.

That may have been done.

 

Thanks guys for posting!

I think I have it in post 1 that my calculated lengths and diameter are optimized for 2200-4600 rpm.
This is the ideal rpm range FOR ME because I designed mine to be most efficient at rpms WE would use for everyday use.
Most (I think) would agree to no loss of low end, with everything above enhanced including up to redline.
I didn't want a top end screamer for daily use as it would rarely be utilized.
Now if I ever get an x-runner then I might tune the exhaust for better top end flow as that would be my play toy/test bed.


@StuckinOhio are you supercharged?

Hope this helps Mr. Stuck

 

On a side note I got a souvenir from Factory KTM off Trystan Hart's bike.
He smashed it during the race and needed a spare (they had spares) so their mech asked me if I wanted it.....duh, then I showed the mech a couple pics of my stuff and he was blown away! Cool stuff!

Its not supposed to be smashed like this for those not familiar with 2stroke expansion chambers.

Anyway its now a shop rafter souvenir.

Hard to breathe with that pinch in it (right where the rafter is).

Overall fun but busy day.

Cheers,

Roost

 

@Roostfactor No i am NA.
2200-4600rpm is definitely usable range.
I use to love the acceleration on the stock header/ URD y-pipe but its was only a WOT pleasure.
Only things missing on my truck are: supercharger/fuel pump/ cam gears/ Uconn.
I no longer tow with my Tacoma, so low end is not as critical. Although towing with a Tacoma really means it's screaming at 3800rpm or higher

@Torspd
I think the hardest part is finding someone that has datalogging capability of the MAF under very similar conditions pre/post.

 

@StuckinOhio, I looked again and you're not supercharged (MAF cal and IM spacer wouldn't apply).

Most likely too large diameter tubes AND of no significant length to support scavenging is what dropped your low end.
It came back with stock y because exhaust velocity increased for the rpms you needed. That velocity aids in scavenging!
What i've done is bump that scavenging efficiency up (more than a few notches) because there was nothing out there previously for our application unlike more common perf engines.

 

That was the understanding i came to, increased velocity after a pressure head, formed an improved vacuum to help scavenging.
I am nervous of replacing the factory catback of 2.25 with 2.5 as it will drop exhaust gas velocity and will be translated back into the y pipe therefore reducing y pipe velocity
So you improved scavenging on a 2.25 system? or was it a 2.5 system?

 

@StuckinOhio we could do the logs pre/post but not the same without same engine config of course.

Not trying to bash but the piggyback system you speak of is waaaaaaaay old news for our application.

We now have HPtuners and tuning god @JustDSM!!!
We now have control over our ecu.
No MAF cal or piggyback needed, direct from the source my friend.

I still have yet to fabricate a 2" y-pipe for the n/a folks as the man himself @JustDSM and I have had conversations about going smaller y-pipe diameters for n/a and I haven't crunched the #s. (he is n/a as well).

Regardless of what you do, I guarantee you wont find better than, well, everything if you get with him and have him personally tune your truck AND you can't beat his price!!!

He is just another dude like me wanting to learn more, cares more about smiles and peoples enthusiasm and doesn't care to make $1M off sales.

Let me be clear I AM NOT INSINUATING ANY COMPANY HERE IN THIS FORUM DOES THIS, just stating that he and I have become friends when I sold him and installed my unused uh hum another name exhaust.

Good thing I was cool with him because he was VERY humble about his previous tuning knowledge and just a quick search in TW will show how bad ass he really is!

Speaking of which, I think I owe him a datalog or 12 to dial me in.......I love my tuner!

 

Exhaust importance generally speaking from most to least importance:

Headers
Y-pipe
Cat back

As long as velocity is optimal at the merge collector at tail end of y-pipe then the cat back mostly either becomes a restriction or it doesn't.
Meaning: exhaust pulse wave timing basically begins at exhaust valve and ends at the y-pipe merge collector (FOR OUR ENGINES), velocity is of less importance after but can restrict flow and prevent scavening upstream if cat back size is insufficient for higher flow demands.

I run and recommend (for now) the URD equal length headers mated to my y-pipe.

Keep in mind this is specifically for our engine as exhaust pulses are always equal and 120° separated.

Stupid quick buzzed drawing but hopefully you get the idea.
There is no way to accurately time the exhaust pulses without equal length.

We are fortunate to have even firing exhaust pulses every 120° so by having desired length and diameter tubing we can control when the most advantageous low pressure occurs at the exhaust valve.
So many variables contribute to the ideal size/length that for our general purpose we have to average. Ever wonder why so many race engines have a powerband like a light switch? This is one of many reasons even on 4strokes.

Ok,
Going sleepy time now and sorry to everyone that I have been absent.

Y'all are THE BEST! SERIOUSLY!!! and have helped me get through everything this year.

That totally includes you @BenMara!!!

 

Thanks @JuanitoBunito and no offense.

I hope I didn't state any names or company.
I will have to check because I dont operate that way.
Not trying to throw anyone or their products under the bus (I run URD headers), simply trying to improve upon whats been established.

Shit, what I saw riders doing today at the extreme enduro race I dont think the top pros from 25 years ago would even consider!?

Progression happens.......we can help it, even and often the little people that dont have to worry about the $$$ as income for mouths to feed.

Seriously my time is worth more than what it takes me to fab a y-pipe at this point but I love everyone here and will always strive for the perfect weld with each and everyone I make because I CARE!!!

@jojotoo feel free to repost your shipping pic.

Ok, rambling, tired, buzzed, good night all.

Roost

 

Iiiiiiif, you are interested, I know a little trick which could strsighten that exhaust out.

 

Some inert gas pressure and heat?

If not text me details or post here. Either is information and is knowlege is good.

I paid a guy like $40 to fix one of mine 20ish years ago but didn't want to tread on his niche.

 

I'm curious too...

 

Hey!!! Don't bash my buddies at iTronix!!

Just kidding, I knew you didn't mean much by that statement... Although I might agree that UCon is 'old news' now, I will stand and defend it - the unit took my 1.87" pulley, Kelford camshafts, water/meth injection, headers.... well you can read my mods list, but the point is, I feel it's done an EXEMPLARY job handling and self-learning for all those mods. It's no slouch, and I know there's serious advantages to HPTuners, but I also feel there's advantages to UCon as well. Data logging is great and customer service is good (admittedly not amazing - Scott has a bit of a mental block around new ideas for how to mod and is in denial sometimes about potential issues with the unit). I'm not just ready to skip to HPtuners yet. My truck, after camshafts and headers installation, hasn't run better.

 

Sorry dude!!

 

The uncovered electrical junction box made me laugh. The previous owner of my home (and garage) didnt seem to believe in them either......then again the PO also occasionally didnt believe in junction boxes at all.

Pretty cool piece of wall art though!

 

Didn't mean to offend anyone and I agree it served my pretty well while I had it installed.

I dont like not knowing what is going on internally but Itronix did work well with me to dial it in.

 

"for now"???

 

I dont have any idea if I will ever fab a header.

It would potentially make things like installation easier as if I did ever make one it would be a header/y-pipe combo with vbands.