A friend of mine has a 1994 Rx-7 twin turbo, stock turbos at 14psi. I was helping him with it the other day and I realized that although he had a nice 70mm (2.8") HKS downpipe and 3" catback (Racing Beat), his midpipe consisted of a 3" cat and custom 3" piping with 4 restrictive bends in it. I took the car over to Henry's Muffler and they helped eliminate the bends.



this is one of the 4 bends we replaced. They don't have a mandrel bender at Henry's but Donald (head guy at the Millbrook shop) cut the ends of the pipe at angles and used the pipe expander to eliminate the crush bends. It's not as clean as nice stainless 3" mandrel bends, but it was way more affordable. We measured the old crush bends and they were about 2.5" at their tightest spots. Now some of the bends were slightly sharper than others, but you get he picture. So the exhaust went from:

~2.8" (HKS 70mm) stainless mandrel bent downpipe --> 3" pipe --> 2.5" bend --> 3" cat --> 2.5" bend --> 3" pipe --> 2.5" bend --> 3" pipe --> 2.5" bend --> 3" pipe mating to 3" stainless mandrel bent catback which just has a muffler and some bends

new exhaust: 2.8" downpipe --> 3" pipe --> 3" cat--> 3" pipe connected to 3" catback.

Results? I wish I could have done a before and after dyno (don't have the loot for that), but pulling out of the shop I inadvertently spun tires merging into traffic. The turbos spool noticeably faster. In first the car spins at 1/4 throttle and gets completely sideways if you floor it (Falken Azenis RT-615 255 width). It hardly ever would spin before, only if you would floor it when it was under 40 degrees outside. I had to retune the Power FC to add fuel (speed density system with no MAF sensor to compensate for increased efficiency).

I don't think crush bends are a huge deal on most applications but for a turbo car at least you really need to stay away from them.

[Edited on October 24, 2008 at 1:22 PM. Reason : .]

10/24/2008 1:21:29 PM

k. I won't.

10/24/2008 1:24:44 PM

umm, i really hope people dont use crush bent exhaust on upgrades..

unless you go with a 5" crush to solve a 3" mandrel solution.

10/24/2008 1:42:07 PM

I guess I'm just reaffirming conventional wisdom.

10/24/2008 1:52:45 PM

3" TURBO FLANGE
3"-4"
4" 45DEG BEND
12" OF 4"
4" 45DEG BEND
4-5"
48" OF 5"
(3) 5" 90DEG BENDS
5-6" , 32" LONG MITRE CUT STACK


THATS HOW I TRUBO

10/24/2008 2:07:46 PM

Quote :

" MITRE CUT SACK "

10/24/2008 2:11:21 PM

they do hang to one side

10/24/2008 2:54:42 PM

ive dealt with donald at the millbrook location and even once or twice at capital before they had the millbrook shop.. he's a cool guy...

10/24/2008 3:53:35 PM

Quote :

"umm, i really hope people dont use crush bent exhaust on upgrades.. unless you go with a 5" crush to solve a 3" mandrel solution."

not trying to flame or troll, arghx, but why in the shit did he have crush bends to begin with?

[Edited on October 24, 2008 at 6:42 PM. Reason : it's common sense that if you crush something it gets smaller]

10/24/2008 6:41:00 PM

should've taken it to RJ's. he's the only one i know of in the area that has a mandrel bender. he does all sorts of custom shit from exhaust to i/c piping. thanks to optmusprimer for the heads-up on that hook up.

10/24/2008 8:51:05 PM

he had crush bends because the owner of the vehicle in question (a friend's dad) is a 54 year old man who doesn't read car forums all day, and the shop that installed the bends told him it wouldn't make all that much of a difference

[Edited on October 24, 2008 at 9:56 PM. Reason : and Mandrel bends from RJ's would've cost more than the $75 Henry's charged]

10/24/2008 9:55:38 PM

^anything is better than stock right?

10/24/2008 10:48:25 PM

i miss my fd

10/24/2008 11:04:59 PM

jeremy's dad's fd? sounded like that thing was modified as hell when I last saw and rode in it. is it back to stock now?

10/25/2008 11:03:44 AM

^ yes that is the one. I've been helping him with the car a lot lately because his dad travels 90% of the time now for work and now I know the quirks of the 3rd gens. It was running rich as crap, it had a surging idle, it had developed a lot of the common Rx-7 electrical problems (starter wiring problems especially), it had the crush bent exhaust... just a bunch of little things. Hopefully the car will get a small single turbo conversion within the next few months for increased reliability.

[Edited on October 25, 2008 at 3:34 PM. Reason : same mods, just trying to get them to work right]

10/25/2008 3:30:26 PM

Quote :

"and Mandrel bends from RJ's would've cost more than the $75 Henry's charged"

How the fuck do you know that? Ron does great work and his pricing is competitive with anyone in the area. Even if it was $25 more, not having some ghetto ass rigged up shit is well worth the hundred bucks.

10/27/2008 11:00:12 AM

This is a valid point, and I don't know the price difference honestly. Henry's was a lot more convenient at the time, about 5 minutes from my parents house where I had spent hours rewiring the starter due to shitty Mazda electrical problems.

It's just a delicate situation because it's not my car, it's my friend's dad's, and I needed to get this done ASAP. I went to the exhaust shop at short notice without telling him and gave him a bill when he came back for the weekend. He wouldn't have been able to pay me back in time if I had set up an appointment at RJ's, and he has never heard of RJ's but knows about Henry's.

Does that make sense? It's just the unusual personal situation.

10/27/2008 11:54:18 AM

small world, i totally remember that car from the drive ins at chargrill. do those still happen?

10/27/2008 11:59:45 AM

^ the group kind of fell apart a couple years ago. A few people unilaterally decided to move the meets to the Mazda dealership (lame) and start their own website instead of organizing through the main rx7 forums. Myself and a lot of other people liked things the way they were, so we voted with our feet.

It's a pretty car though, isn't it?

10/27/2008 12:10:55 PM

No it doesn't make sense. Henry's and RJ's are two totally different kinds of shops. Stop by and talk to Ron sometime, check out his Nissan, look at his equipment, maybe even have him do some work for you and you will forget about the hassle of dealing with Henry's and their rushed, sloppy work ever again.

10/27/2008 12:11:11 PM

in the future I will speak to RJ's. I need a full custom downpipe made for my own car which will recirculate my new wastegate.

10/27/2008 12:12:56 PM

Who's RJ? He that guy in Apex? I'm gonna need some custom longtube headers one day and I want the job done right this time... (I'm not trying to hi-jack)

^^^ Yeah, I used to hang with that RX crowd. It's such a small group now, I don't even know if they meet up anymore... :/ Does Greg work at Harry's Guitar Shop downtown off Glennwood?

[Edited on October 27, 2008 at 12:42 PM. Reason : .]

10/27/2008 12:40:52 PM

rjs is good, but i have seen at one piece of questionable work come out of there..

he did a friends intake/intercooler piping and had the dv recirculating back into the intake piping in a way that it was blowing air backwards across the maf, thus causing some false readings and other issues when you lift off throttle. there was also a 4" -> 3" section that was a little sloppy looking (although i dont know how else he could have done it with the space constraints). this guy also had all of his piping and exhaust done there and everythign else turned out great. and rj fixed the dv issue.

he did ic piping for another friends car that had the routing done to his specifications (not typical for this type of setup) and it turned out great..

that said, we will usually send people over to ronnie if they need custom exhaust/piping work...

pics of the first guy's car here:
http://ncdubs.org/forum/album.php?albumid=2
ronnie did the full turboback (external wastegate rerouted back into downpipe), and all of the intercooler/intake piping.


[Edited on October 27, 2008 at 12:54 PM. Reason : ..]

10/27/2008 12:49:02 PM

RJ's in Raleigh (Ron) != R&J in Apex

10/27/2008 12:53:44 PM

yes, RJs in raleigh. behind carmax place.

he used to be on new bern. that's where he did this stuff. he used to be less than a mile from our shop.

it was only that one transition (you can see it in the pics) and the dv, which he fixed and it works fine now.


[Edited on October 27, 2008 at 12:55 PM. Reason : i am not talking shit, he does good work...]

10/27/2008 12:54:49 PM

also, to be fair, the guy with the white car (pics above) could have gotten a nice 3-4" taper if he had done stainless, but he insisted on aluminum (for the intake/ic piping) and wasnt able to find this piece.

everything else ronnie touched on the car came out great (wastegate flange on downpipe needed some slight adjustment) he was really good about fixing things to make everything work properly.

[Edited on October 27, 2008 at 12:59 PM. Reason : ..]

10/27/2008 12:57:37 PM

well when I get my downpipe made, I'm not just going to drop the car off and tell him to go to town then leave. I will consult with him the whole time and be there for much of the fabrication if possible, even if it takes a few hours. I'm especially concerned about the placement of the O2 bung for the wideband and the way the wastegate will be routed back into the main exhaust stream.

10/27/2008 3:39:14 PM

Now I am pretty cool, easy to get along with, know how to behave myself in a shop and all that, and Ron had no problem with me hanging out while he worked on both of the trucks that I took to him. In fact, I would say on the custom work I had him do he probably preferred input from me so that I would be totally satisfied. But I will say that its hard to do a good job if a bunch of beady eyed ricer fanboys come in and crawl all over the shop while you are trying to work. Beethead, Brian, Will, Karoush, myself, all have worked in shops and I am sure we can all agree on this.

10/27/2008 3:54:34 PM

you need to calculate your reynolds number to stay within laminar flow, and your friction loss over the length of the tubing, blah blah, fuk thermo bigger is better

10/27/2008 5:53:15 PM

^laminar flow my ass.

10/27/2008 6:15:03 PM

primer is right... its one thing to wait in the lobby and ask him to call in you every time he moves to the next stage. but ill be damned if he's gonna want you in the actual shop watching him do work and spouting everything you may know about exhaust.

let him do his job, dont help him. he doesnt need it. if you're there blabbering about what it needs to look like and stuff then i hope he kicks you out and tells you to go somewhere else.
go in there for a consult, tell him what you want. there is nothing wrong with not liking what he did and saying you dont want it. but i doubt thats gonna be the case with him. he does really good work.

you dont even gotta tell him what you want, you can just tell him what it needs..

and he'll put something on there that you'll like.

10/27/2008 6:38:40 PM

Personally, no work is being done to my vehicles if I'm not allowed to watch. I never comment, in fact I speak when spoken to and try to stay the fuck out of the way even if it's something I know how to do and simply lack the equipment for, but if they have a problem with me simply watching then I don't feel comfortable with their work.

I've never actually had a shop complain about this and usually they make small talk with me while they work, but you guys that have actually worked in a shop environment feel free to let me know if this is asking too much

[Edited on October 27, 2008 at 7:00 PM. Reason : .]

10/27/2008 6:57:54 PM

yeah that should be fine... watching him work.

but a lot of places have liability issues. but most shops dont mind if you just look

if its just general maintenance, you really shouldnt need to look.. and if you have any doubts, take it somewhere else.

i goto shops i know, so everytime its a friend, or someone i know well that works on my cars, so they dont mind at all if i hang around. and i still dont talk, unless i have a Q.

[Edited on October 27, 2008 at 7:07 PM. Reason : ]

10/27/2008 7:04:08 PM

Yes it is asking too much.

10/27/2008 7:05:28 PM

Quote :

"Personally, no work is being done to my vehicles if I'm not allowed to watch. I never comment, in fact I speak when spoken to and try to stay the fuck out of the way even if it's something I know how to do and simply lack the equipment for, but if they have a problem with me simply watching then I don't feel comfortable with their work. I've never actually had a shop complain about this and usually they make small talk with me while they work, but you guys that have actually worked in a shop environment feel free to let me know if this is asking too much "

SHOP LABOR RATES
$75 per hour
$150 per hour if you watch
$500 per hour if you help

[Edited on October 28, 2008 at 12:47 AM. Reason : nigger titties]

10/28/2008 12:47:27 AM

10/28/2008 12:51:02 AM

yeah if i was doing exhaust (welding) and someone wanted to stand over my shoulder i would get a little irritated. there is definitely a liability issue if you get hurt.

ronnie is good.. i've actually dropped parts off and he called when they were ready (just a little fix on a map sensor flange).. he's really good about understanding what you want/need and getting it done right....

10/28/2008 2:24:33 AM

Quote :

"No it doesn't make sense. Henry's and RJ's are two totally different kinds of shops. Stop by and talk to Ron sometime, check out his Nissan, look at his equipment, maybe even have him do some work for you and you will forget about the hassle of dealing with Henry's and their rushed, sloppy work ever again."

i agree. i'd probably never go back to henry's now that i know of RJ's. nothing against henry's. i've been using them for 10+ years. but i had ron do the cat-delete pipe on my truck and couldn't have been more impressed. henry's wouldn't have even touched the job much less had the equipment to flare and reduce 4" pipe.

Quote :

"Now I am pretty cool, easy to get along with, know how to behave myself in a shop and all that, and Ron had no problem with me hanging out while he worked on both of the trucks that I took to him. In fact, I would say on the custom work I had him do he probably preferred input from me so that I would be totally satisfied. But I will say that its hard to do a good job if a bunch of beady eyed ricer fanboys come in and crawl all over the shop while you are trying to work. Beethead, Brian, Will, Karoush, myself, all have worked in shops and I am sure we can all agree on this."

exactly. ron was totally cool. of course, it helped that i got him and phantasm working together now to custom build i/c piping but one thing i did like about him is he did want my input on what i thought about his opinion on how stuff should line up and how it should be reduced. most shop guys i know are going to have the "it's my way or take the shit home and do it yourself" attitude.

10/28/2008 10:27:02 AM

Quote :

"^ the group kind of fell apart a couple years ago. A few people unilaterally decided to move the meets to the Mazda dealership (lame) and start their own website instead of organizing through the main rx7 forums. Myself and a lot of other people liked things the way they were, so we voted with our feet. "

that sucks. the last meet i went to was the one out in the country the "grand rotary rally" or whatever they called it. I won a nice set of jumper cables in the raffle but ended up forgetting them at the guys house. things were pretty nice the way they were. there was usually a good mix of people/cars and everyone always seemed really nice. having meets at the dealership seems like a terrible idea as would breaking away from rx-7 club.

10/28/2008 11:35:49 AM