Justjim75
Justjim75 HalfDork
12/6/18 11:58 p.m.

Is there a link someone can direct me to with info on "x power was made by x product"?

NickD
NickD UberDork
12/7/18 5:25 a.m.

By and large, exhaust mods on a 1.8L aren't going to pick up much in the way of power (the exception being tossing the '99-'00 exhaust manifold)

Dusterbd13-michael
Dusterbd13-michael MegaDork
12/7/18 6:44 a.m.

Supposedly the 01 up manifold makes a solid 8-10 hp over the 99-00 manifold. 

Read somewhere, no direct experience or numbers to back it up.

ShinnyGroove
ShinnyGroove New Reader
12/7/18 7:22 a.m.

My understanding is that intake/header/exhaust could get you around 15-20hp, but only with an aftermarket ECU that you can tune to realize the advantages.

Snrub
Snrub HalfDork
12/7/18 7:34 a.m.

It's been a while since I investigated/implemented an exhaust on a miata, but I believe a muffler can be worth 4-6hp, header 0-4hp, cat 0-2hp and perhaps a couple of hp for the general improvement with pipes. There's no easy/free lunch for power on a n/a miata. Intake can be ~4-6hp. I'm trying to think where you can find this info...  Flyinmiata use to have a dyno section on their website, but no more. Search around miata.net?

z31maniac
z31maniac MegaDork
12/7/18 9:12 a.m.

Spend a few days reading the large number of threads regarding this over on miataturbo.net. There is tons of NA information there. 

Rodan
Rodan HalfDork
12/7/18 9:45 a.m.

Best stock manifold for 1.8 is the 2001 up NB2 header.  It will make as much power as any of the cheap eBay headers.  Racing Beat is the gold standard header of stuff that's readily available and will make ~5hp more than the NB2 stocker.  As long as the exhaust behind the header is of decent quality, there's not much power to be found there.  A cat delete is usually only a couple HP on an otherwise good setup.  Some of the Spec Miata systems are probably the best, because they're looking for every last bit.  Unfortunately, they're usually earsplittingly loud, and sound like crap.

To make the most of any intake/exhaust mods on a naturally aspirated Miata, you're going to need an aftermarket ECU.

Justjim75
Justjim75 HalfDork
12/7/18 11:33 a.m.

My car will eventually get a turbo, so upgrading everything I can before then that will support that mod.  Maybe should have mentioned that but I assumed if there was a page it would have turbo and NA available.  Wont be messing with the header unless one falls in my lap. 2.25", 2.5" or 3" cat back? Just trying to get some data so I can do things right the first time.  Thanks for the replies

Megasquirt is this summer

KyAllroad (Jeremy)
KyAllroad (Jeremy) PowerDork
12/7/18 1:08 p.m.

I failed to dyno my car before the mods went on but I can tell you that mine with a stock/unopened 100K mile 97 pulled 115 RWHP.  Most comparable Miatai on the same dyno (really the only apples to apples comparison) were in the 105 range.  However there was, as Keith likes to point out, much more space under the curve all the way through and the car was still pulling "hard" at the rev limiter rather than falling on it's face around redline. 

The bolt ons were a Jackson Racing 4-2-1 header, FM full exhaust w/ high flow cat, Racing Beat intake, just a bit of timing advance (not too much, it will sound good but actually lose significant power if you over advance it) on Shell 93.

z31maniac
z31maniac MegaDork
12/7/18 1:17 p.m.
Justjim75 said:

My car will eventually get a turbo, so upgrading everything I can before then that will support that mod.  Maybe should have mentioned that but I assumed if there was a page it would have turbo and NA available.  Wont be messing with the header unless one falls in my lap. 2.25", 2.5" or 3" cat back? Just trying to get some data so I can do things right the first time.  Thanks for the replies

Megasquirt is this summer

I'd just wait until you do the turbo. No point in getting a header/etc, when it will be replaced by a turbo manifold/DP/etc down the line.

Rodan
Rodan HalfDork
12/7/18 4:12 p.m.

This is where the stock NB2 header can be a good choice... it's cheap, and it bolts up to stock and aftermarket exhaust.  It's easy to re-sell down the road if you go turbo.   And it's usually within ~5-6hp of the good aftermarket headers.

You can use NB exhaust on an NA if you move the hangers, and if you build/buy one in 2 1/2", it will be sufficient for a mild turbo build.  

 

Justjim75
Justjim75 HalfDork
12/7/18 4:55 p.m.

In reply to z31maniac :

I just said I'm not getting a header and an exhaust upgrade from the cat back now saves time and money at turbo time.

Justjim75
Justjim75 HalfDork
12/7/18 4:58 p.m.

In reply to KyAllroad (Jeremy) :

Thank you, very helpful.  I'm gathering from multiple sources that FM or the parts they sell is the way to go with all things Miata

codrus
codrus UltraDork
12/7/18 5:11 p.m.
Rodan said:

This is where the stock NB2 header can be a good choice... it's cheap, and it bolts up to stock and aftermarket exhaust.  It's easy to re-sell down the road if you go turbo.   And it's usually within ~5-6hp of the good aftermarket headers.

You can use NB exhaust on an NA if you move the hangers, and if you build/buy one in 2 1/2", it will be sufficient for a mild turbo build.  

 

Marginal, perhaps.  IMHO 3" is worth it even on a mild build because it helps the turbo spool a lot faster.

My advice is not to bother with NA exhaust work now if you're going turbo later.  You're not going to want to reuse any of it -- the turbo does a lot of muffling all on its own, and also demands a very free flowing exhaust.  This means that a good turbo exhaust will be really loud on an NA car, and a decent NA exhaust too restrictive on a turbo.

 

 

Keith Tanner
Keith Tanner MegaDork
12/7/18 5:13 p.m.
Justjim75said:

In reply to KyAllroad(Jeremy) :

Thank you, very helpful.  I'm gathering from multiple sources that FM or the parts they sell is the way to go with all things Miata

Well, I think so... :) I took that dyno page down because it was getting pretty dated, lots of tests done with parts that were NLA and several different dynamometers.

FYI, an aftermarket ECU is worth 10 hp on its own. We did a test years ago where we took a stock car, dynoed it, and plugged in a Link ECU while it was still on the dyno. 7 hp, and that was on the bone standard default tuning with an ECU that is viewed as fairly antique these days but is probably a good comparison to a Megasquirt 2. GRM put the same ECU in a car and got something like 15. So if the plan is for a turbo eventually and your emissions regulations allow it - do the ECU now. 

Justjim75
Justjim75 HalfDork
12/7/18 10:41 p.m.

In reply to Keith Tanner :

Thank you and yessir!. Like I said, I'm trying to do this in stages and understand that a  DIY Megasquirt takes time and a little less money and will yield positive results all by itself with an experienced tuner, which I am not, but a very good friend is.  And has his own personal dyno.  He is the guy that folks in Sweden call for tuning advice on Volvos. DIY MS3, wideband and bigger free flowing exhaust all make power together and are required to turbo, so that's the plan.  My wife is a public school elementary teacher and I repair and maintain medical equipment so I can't afford to just order Happy Meals and LS swaps willie nilly so I have to build up to it

Keith Tanner
Keith Tanner MegaDork
12/8/18 7:29 a.m.

That’s the big advantage of a turbo over an engine swap - you can go bit by bit. Although buying the clutch and flywheel separately means a heck of a lot more work on install. 

Listen to Codrus on the exhaust, though. A proper turbo exhaust is way, way too loud on a naturally aspirated car. 

Justjim75
Justjim75 HalfDork
12/8/18 8:53 a.m.

So a 3" cat back will suck? Hmmm, maybe enough to speed the turbo installation along.  My gears are turning

iceracer
iceracer UltimaDork
12/8/18 11:36 a.m.

In reply to ShinnyGroove :

I expect the ECU would be the major power proucer.

Witness the ZX2SR.  Only a slight change to the intake resulted in app. 13 hp.    It was plug and play.

 Under drive pulley,  shorty header,  cat back,   chip, resulted in maybe 7 hp.    The pulley being the biggest increaser.

Keith Tanner
Keith Tanner MegaDork
12/8/18 2:17 p.m.
Justjim75 said:

So a 3" cat back will suck? Hmmm, maybe enough to speed the turbo installation along.  My gears are turning

Depends on the muffler stuck on the end. If it’s a properly designed system for turbo use, it will suck without a turbo. If it’s some blingy eBay can, nobody knows. 

Justjim75
Justjim75 HalfDork
12/8/18 3:04 p.m.

Will a wideband talk to the stock ECU in place of a standard O2 sensor?  Tuning buddy says some cars do and some dont.

Keith Tanner
Keith Tanner MegaDork
12/8/18 8:09 p.m.

It will not. Very different signal. 

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