Engine Performance This section is for discussion on all engine building related questions.
Sponsored by:
Sponsored by: KPower

Is my exhaust a major bottleneck?

Thread Tools
 
Search this Thread
 
Old 08-17-2016, 12:11 AM
  #1  
Junior Member
Thread Starter
 
Rshannon81's Avatar
 
Join Date: Nov 2015
Posts: 67
Total Cats: -6
Default Is my exhaust a major bottleneck?

I'm running a stock 1.6, greddy turbo/manifold, 2.5" downpipe, and a 2.5" crush bent exhaust straight pipe all the way back. I figure the effective diameter of the crushes are in the realm of 2-2 1/4". I'm currently running 17psi spraying 100% meth with a 575mL/hr nozzle and @ 20* of timing up top. According to v dyno I'm at about 260whp. Take that as it is and it may not be accurate, but from what I can compare it to it's at least somewhat close. I'm wondering if I will see any noticeable gains from putting on a 2.5" mandrel bent exhaust, whether it be spool or power. I currently see 17psi by 4400rpm or so but I've also kept timing fairly conservative to keep torque down to save the 5 speed and my rods. Any input is appreciated.
Rshannon81 is offline  
Old 08-17-2016, 12:16 AM
  #2  
VladiTuned
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 35,821
Total Cats: 3,481
Default

3" or go home. and yes you should pick up power and torque and spool
I seriously doubt you're making that power figure on your setup, but you already mentioned that.
18psi is offline  
Old 08-17-2016, 12:21 AM
  #3  
Junior Member
Thread Starter
 
Rshannon81's Avatar
 
Join Date: Nov 2015
Posts: 67
Total Cats: -6
Default

Sweet. 3" it is then. I've tried adding more timing after meth and I didn't gain any power up top. I'll be adding boost once the 6 speed is in next weekend. I'm hoping to break 300 with the stock block and this turbo. From what I can see on the compressor map it started dropping efficiency once I go past 18psi or so. I'll see what this baby turbo can do though. Any suggestions to squeeze more out of my shitty motor?
Rshannon81 is offline  
Old 08-17-2016, 12:24 AM
  #4  
VladiTuned
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 35,821
Total Cats: 3,481
Default

basically let it breathe
make sure intake/fmic/piping doesn't have bottlenecks either, the greddy did come with that terrible elbow.

throw it on the dyno afterwards, I'm guessing 250-270 all said and done, and 240ish currently
18psi is offline  
Old 08-17-2016, 12:26 AM
  #5  
Junior Member
Thread Starter
 
Rshannon81's Avatar
 
Join Date: Nov 2015
Posts: 67
Total Cats: -6
Default

Intake piping is larger than turbo inlet, IC piping is custom 2.5" with a mishimoto z-line. Could be some gains to be had there if I remove some of the 90s and such. But that's more work than I want to do before the 1.8 is in. Don't think 300 is possible with this turbo?
Rshannon81 is offline  
Old 08-17-2016, 12:30 AM
  #6  
VladiTuned
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 35,821
Total Cats: 3,481
Default

I dunno if I'd say impossible, but I'd be extremely impressed to see it.

Back in the day we had guys with "optimized" greddy setups and all seemed to be around 250 full tilt, don't remember if they were spraying down the house with meth though.

Give it a shot. The funnest times I've had was tuning cars where no one cared about the engine and we tried different things...."for science"
18psi is offline  
Old 08-17-2016, 12:33 AM
  #7  
Junior Member
Thread Starter
 
Rshannon81's Avatar
 
Join Date: Nov 2015
Posts: 67
Total Cats: -6
Default

I agree 100% with that. I'm one to love testing my limits. And testing them as a tuner sounds really fun. Hopefully when the exhaust goes on I can make more with timing. If it blows up that's more incentive to begin my 1.8 build is all. Does anyone sell 3" exhausts that aren't overpriced as hell? Or should I have the local shop crush bend a 3.5" to make due?
Rshannon81 is offline  
Old 08-17-2016, 12:43 PM
  #8  
Junior Member
 
bjorno's Avatar
 
Join Date: Apr 2016
Location: Seattle
Posts: 68
Total Cats: 3
Default

flyin sells 3" exhausts for ~$750, but that is probably 'overpriced as hell'.
bjorno is offline  
Old 08-17-2016, 12:52 PM
  #9  
VladiTuned
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 35,821
Total Cats: 3,481
Default

enthuza has a budget option that's cheap. 450?
18psi is offline  
Old 08-17-2016, 01:54 PM
  #10  
Elite Member
iTrader: (4)
 
hornetball's Avatar
 
Join Date: Mar 2008
Location: Granbury, TX
Posts: 6,301
Total Cats: 696
Default

Enthuzas are great. Highly recommend them.
hornetball is offline  
Old 08-17-2016, 04:40 PM
  #11  
Elite Member
iTrader: (17)
 
pdexta's Avatar
 
Join Date: Aug 2007
Location: Knoxville, TN
Posts: 2,949
Total Cats: 182
Default

You could always pull the rear section of the exhaust off to see what virtual dyno says with an open downpipe. Maybe it's just because I'm poor, but for me it'd be worth seeing what difference it makes before spending money on a bigger exhaust. I would think a straight through 3" shouldn't really lose anything over an open downpipe on your setup.
pdexta is offline  
Old 08-18-2016, 12:44 AM
  #12  
Junior Member
Thread Starter
 
Rshannon81's Avatar
 
Join Date: Nov 2015
Posts: 67
Total Cats: -6
Default

I plan on testing with open downpipe. Yes 750 is "overpriced as ****" everything from ******' Miata is. Aside from a few things like their clutches.
Rshannon81 is offline  
Old 08-18-2016, 11:10 AM
  #13  
mkturbo.com
iTrader: (24)
 
shuiend's Avatar
 
Join Date: May 2006
Location: Charleston SC
Posts: 15,176
Total Cats: 1,680
Default

$750 isn't over priced as ****. Go price out the cost of stainless steel for materials. Then factor in the cost of labor to build and exhaust. Yes they have it all jigged out, and make some money off them, but they definitely are not over priced.
shuiend is offline  
Old 08-18-2016, 11:14 AM
  #14  
VladiTuned
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 35,821
Total Cats: 3,481
Default

But bro, he can pay like 100 less for a birdpoo welded mismatched crushbent pile of garbage from the local place?
lol

But yeah, 750 for a full exhaust with quality materials and perfect fitment is by no means overpriced.
18psi is offline  
Old 08-18-2016, 11:30 AM
  #15  
mkturbo.com
iTrader: (24)
 
shuiend's Avatar
 
Join Date: May 2006
Location: Charleston SC
Posts: 15,176
Total Cats: 1,680
Default

I just looked and the FM one includes a CAT in it also. So it is priced about $50 more then Enuthza, so honestly not badly priced at all.
shuiend is offline  
Old 08-19-2016, 05:19 PM
  #16  
Junior Member
Thread Starter
 
Rshannon81's Avatar
 
Join Date: Nov 2015
Posts: 67
Total Cats: -6
Default

I find it hilarious how big of a circle jerk there is for FM. Literally everything on their website can be found cheaper elsewhere. It may be quality stuff, but it's overpriced.
Rshannon81 is offline  
Reply
Leave a poscat -2 Leave a negcat
Old 08-19-2016, 06:17 PM
  #17  
mkturbo.com
iTrader: (24)
 
shuiend's Avatar
 
Join Date: May 2006
Location: Charleston SC
Posts: 15,176
Total Cats: 1,680
Default

Originally Posted by Rshannon81
I find it hilarious how big of a circle jerk there is for FM. Literally everything on their website can be found cheaper elsewhere. It may be quality stuff, but it's overpriced.
I'm not circle jerking anyone all I am talking about is their exhaust. I build exhausts. I know what material prices are. I know what labor prices are. They are not over priced for what you get. Enthuza is the next well known quality exhaust maker and he is only $50 cheaper then FM for the same stuff.
shuiend is offline  
Old 08-19-2016, 08:13 PM
  #18  
Junior Member
iTrader: (1)
 
Pretending2koolz's Avatar
 
Join Date: Jan 2016
Location: Utah
Posts: 109
Total Cats: -30
Default

I got my exhaust from the fence supply store, and mandrel pipe from Columbia river. Gained tons of spool. Like $48 total.
Pretending2koolz is offline  
Reply
Leave a poscat -1 Leave a negcat
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
95Mmiata
MSPNP
22
08-21-2016 01:59 PM
rndmheroxx
Miata parts for sale/trade
10
06-19-2016 11:55 AM
Endre Lund
WTB
0
06-02-2016 10:47 AM
george482
DIY Turbo Discussion
6
06-01-2016 01:07 AM
Bond
Cars for sale/trade
2
05-27-2016 09:58 AM



Quick Reply: Is my exhaust a major bottleneck?



All times are GMT -4. The time now is 10:04 AM.