Kinda bummed out... No Exintake Mod? - Page 2 - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


General Miata Chat A place to talk about anything Miata

Reply
 
 
 
LinkBack Thread Tools
Old 07-01-2008, 11:41 PM   #21
Elite Member
iTrader: (21)
 
paul's Avatar
 
Join Date: Jun 2006
Location: Point Pleasant, NJ
Posts: 2,957
Total Cats: 2
Default

what do you think a worked head worth telling your friends about is gonna run?
paul is offline   Reply With Quote
Old 07-01-2008, 11:50 PM   #22
Junior Member
Thread Starter
iTrader: (12)
 
Join Date: Oct 2007
Location: Central, NJ
Posts: 487
Total Cats: 1
Default

$699.99
MikeRiv87 is offline   Reply With Quote
Old 07-02-2008, 12:01 PM   #23
Elite Member
iTrader: (9)
 
TurboTim's Avatar
 
Join Date: Jun 2006
Location: Chesterfield, NJ
Posts: 6,484
Total Cats: 248
Default

20hp...isn't that about 2psi extra boost? Not worth $700 IMHO.

I have always wanted to do the exhintake mod (have an extra cam from paul) but I think it gives you more overlap not less (assuming you just redrill the OEM gear where "they" tell you to), and I think that's not good for a turbo car.

If I were real cool I'd put both intake and exhaust cams on our camdoctor and get real numbers. If I were even more cool I'd get Tom's (brgracer) FM head and flow test it along with a 99 head (already flowed) and a stock 94 head (at the head shop still to be flowed).
TurboTim is offline   Reply With Quote
Old 07-02-2008, 01:19 PM   #24
Elite Member
iTrader: (39)
 
Zabac's Avatar
 
Join Date: Sep 2007
Location: High Point NC
Posts: 4,854
Total Cats: 8
Default

You can buy a 99/00 head for sub $500 and port polish it yourself with $40 worth of bits.
Now quit bitching and do something productive, ask Ben if he has 99 head still for sale..

on subject, seems the exintake will give gains, how much? Dyno and find out.
Stock intake cam: 233 .318"/8.08mm
Stock exhaust cam: 254 .339"/8.61mm

233 is not enough duration regardless if you are NA or FI, you will benefit from more duration (254) either way.
Same goes for the lift, even though I don't see .53mm more lift doing much without FI though.

Last edited by Zabac; 07-02-2008 at 01:55 PM.
Zabac is offline   Reply With Quote
Old 07-02-2008, 02:40 PM   #25
Ben
Supporting Vendor
iTrader: (33)
 
Ben's Avatar
 
Join Date: Jul 2006
Location: atlanta-ish
Posts: 12,689
Total Cats: 99
Default

Quote:
Originally Posted by Zabac View Post
Now quit bitching and do something productive, ask Ben if he has 99 head still for sale..
No. Don't perpetuate these rumors and lies.
Ben is offline   Reply With Quote
Old 07-02-2008, 02:57 PM   #26
hrk
Junior Member
iTrader: (6)
 
Join Date: Oct 2005
Location: Atlanta GA
Posts: 335
Total Cats: 2
Default

Word
https://www.miataturbo.net/forum/showthread.php?t=18325
Completely stock motor with 90,000 miles
Add turbo and exhintake cam with adjustable gears.

Cam change can be done easily in one evening and costs less than $100, why not do it?

hrk
hrk is offline   Reply With Quote
Old 07-02-2008, 03:03 PM   #27
Elite Member
iTrader: (39)
 
Zabac's Avatar
 
Join Date: Sep 2007
Location: High Point NC
Posts: 4,854
Total Cats: 8
Default

Quote:
Originally Posted by Ben View Post
No. Don't perpetuate these rumors and lies.
No need to get all defensive, didn't mean to get you spammed
Zabac is offline   Reply With Quote
Old 07-02-2008, 05:05 PM   #28
Elite Member
iTrader: (3)
 
AbeFM's Avatar
 
Join Date: Aug 2006
Location: San Diego, CA
Posts: 3,048
Total Cats: 8
Default

Quote:
Originally Posted by hrk View Post
Word
https://www.miataturbo.net/forum/showthread.php?t=18325
Completely stock motor with 90,000 miles
Add turbo and exhintake cam with adjustable gears.

Cam change can be done easily in one evening and costs less than $100, why not do it?

hrk
No to jump on the bandwaggon, but what's there to do for an NB? Are the MSM cams any better? Is there anything cheap to do in that dept? I already have slightly oversized valves, a bunch of various grinding on things. No adjustable gears or non-stock cams, though.
AbeFM is offline   Reply With Quote
Old 07-02-2008, 05:24 PM   #29
Elite Member
iTrader: (39)
 
Zabac's Avatar
 
Join Date: Sep 2007
Location: High Point NC
Posts: 4,854
Total Cats: 8
Default

Quote:
Originally Posted by AbeFM View Post
but what's there to do for an NB?
A lot of stuff.

Quote:
Originally Posted by AbeFM View Post
Is there anything cheap to do in that dept?
Nothing really.
Zabac is offline   Reply With Quote
Old 07-02-2008, 08:02 PM   #30
Junior Member
iTrader: (7)
 
Join Date: Jun 2005
Location: Texas
Posts: 376
Total Cats: 16
Default

Quote:
Originally Posted by MikeRiv87 View Post
From what i've read they net about 8-10hp on an NA but how they cams will be setup after the mod they are actually supposed to be a good setup for a turbo car. Less overlap or something...
Having run the exhintake cam NA and boosted - I have a lot of doubts about what actually gives the 8-10whp. I don't think any of the exhintake pioneers had a standalone ecu. Heck, they didn't even have a wideband. They were all running flapper AFM's. Turning the clockspring on an AFM and adjusting the bypass screw does NOT constitute tuning an AFM. You can shift the fuel curve up and down but you can't change the span or the shape of the curve. (seriously, don't get me started on AFM's)

The AFM is way lean down low and too rich up top. My feeling is that the exhintake cam helps to bring the high rpm afr's into only a slighly rich range instead of the stock ridiculously rich setting.

On my 96 1.8, with wideband, with standalone ecu, it was tuned pretty well on WOT. After exhintake installation it required retuning. Every small cam timing change required pretty significant retuning.

My butt dyno can definitely detect 8-10whp and the exhintake did not give that much when comparing apples to apples (tuned before and after vs never tuned).

If you are doing it on the cheap, then drill the hole in the stock gear. If you want to do it right, get adjustable cam gears. I'm pretty sure that drilling per the instructions on m.net adds more than stock overlap. This may or may not be bad for turbo depending on what you setup is.

Adjusting the cam timing did shift the powerband a bit. When tuning for top end it just lost way too much on the low/mid that I set it for low/mid power. Figured that would work better for the turbo install.

It's because of hrk's results that I did the exhintake. It seemed that he got more power out of less boost than most.

I still need to play with cam timing someday. The little bit that I did before was marred by tuning/laptop issues (when adjusting the exhaust cam I was putting in a global ignition offset, so I thought, then the serial port died on the laptop). I need to install the EGT to adjust overlap, I think.

Bottom line: It doesn't do miracles on a tuned NA motor, it might help on an untuned NA and it might do some good on a boosted motor but no one knows just how much.
dvcn is offline   Reply With Quote
Old 07-02-2008, 09:59 PM   #31
Junior Member
Thread Starter
iTrader: (12)
 
Join Date: Oct 2007
Location: Central, NJ
Posts: 487
Total Cats: 1
Default

Quote:
Originally Posted by hrk View Post
Cam change can be done easily in one evening and costs less than $100, why not do it?
Exactly Why not?
MikeRiv87 is offline   Reply With Quote
Old 07-04-2008, 03:11 AM   #32
Junior Member
 
Join Date: Jun 2005
Location: Huntington Beach, CA
Posts: 354
Total Cats: 0
Default

Quote:
Originally Posted by dvcn View Post
I don't think any of the exhintake pioneers had a standalone ecu. Heck, they didn't even have a wideband. They were all running flapper AFM's. Turning the clockspring on an AFM and adjusting the bypass screw does NOT constitute tuning an AFM. You can shift the fuel curve up and down but you can't change the span or the shape of the curve. (seriously, don't get me started on AFM's)

The AFM is way lean down low and too rich up top. My feeling is that the exhintake cam helps to bring the high rpm afr's into only a slighly rich range instead of the stock ridiculously rich setting.
1.8L = no flapper
iWeasel410 is offline   Reply With Quote
Old 07-04-2008, 09:16 AM   #33
Junior Member
iTrader: (7)
 
Join Date: Jun 2005
Location: Texas
Posts: 376
Total Cats: 16
Default

Quote:
Originally Posted by iWeasel410 View Post
1.8L = no flapper
The first person to run the exhintake was a Protege guy, 1.8 w/AFM. A couple other followed. IIRC, others were 1.8 into 1.6 chassis swaps.

The MAF on the later cars doesn't make tuning better.

My point is that most of the NA power gain by the cam swap is probably from the afr correction.
dvcn is offline   Reply With Quote
Old 07-04-2008, 10:02 AM   #34
Elite Member
iTrader: (21)
 
paul's Avatar
 
Join Date: Jun 2006
Location: Point Pleasant, NJ
Posts: 2,957
Total Cats: 2
Default

Quote:
Originally Posted by hrk View Post
Word
https://www.miataturbo.net/forum/showthread.php?t=18325
Completely stock motor with 90,000 miles
Add turbo and exhintake cam with adjustable gears.

Cam change can be done easily in one evening and costs less than $100, why not do it?

hrk
Would have been helpful to see dyno curves before and after exintake mod.

Has anyone EVER done that on a Miata motor with a turbo? That's what we want to see.

those are nice numbers though for that turbo on that motor.
paul is offline   Reply With Quote
Old 07-06-2008, 04:30 PM   #35
Elite Member
iTrader: (11)
 
Join Date: Jun 2007
Location: Overland Park, Kansas
Posts: 5,382
Total Cats: 43
Default

Quote:
Originally Posted by dvcn View Post
Bottom line: It doesn't do miracles on a tuned NA motor, it might help on an untuned NA and it might do some good on a boosted motor but no one knows just how much.

Kinda sounds like it might just be a waste of time for a properly tuned car. You'd think with that significant difference in duration it'd actually do more..
elesjuan is offline   Reply With Quote
Old 07-06-2008, 09:16 PM   #36
Elite Member
iTrader: (11)
 
Join Date: Jun 2007
Location: Overland Park, Kansas
Posts: 5,382
Total Cats: 43
Default

Edit:

Been doing some looking around and I'm curious..

What about swapping in two exhaust cams from a 99-00 BP? From what I can find they're a little more aggressive than the BP HLA camshafts are. Far as I can tell the Miata and Protege HLAs are identical on exhaust, but intake the miata cams are slightly more duration..

Corksport sells some 205 duration .352 lift cams IIRC are turbo friendly grinds... Stock is 190 intake and 202 exhaust with .338 lift. Theres not much improvement there for $600... dammit.
elesjuan is offline   Reply With Quote
Old 07-07-2008, 10:28 AM   #37
Junior Member
iTrader: (7)
 
Join Date: Jun 2005
Location: Texas
Posts: 376
Total Cats: 16
Default

I'm not trying to discourage anyone from doing the install. My experience is just one poorly executed datapoint.

I'm suggesting that if you are turbo, install the cam and adjustable gears. Take the time to properly retune every time a change is made.

I will make a sizable donation to anyone who will provide printouts with dyno, afr's, boost, IAT's, cam timing, ignition timing, fuel, EGT's..... and I'll stop there. This must be done in 2 increments to determine best split and advance/retard at various boost levels(10, 15, 20psi) on a 240whp-350whp otherwise stock 1.8.

I'm serious!
dvcn is offline   Reply With Quote
Old 07-07-2008, 12:58 PM   #38
Ben
Supporting Vendor
iTrader: (33)
 
Ben's Avatar
 
Join Date: Jul 2006
Location: atlanta-ish
Posts: 12,689
Total Cats: 99
Default

Quote:
Originally Posted by dvcn View Post
I will make a sizable donation to anyone who will provide printouts with dyno, afr's, boost, IAT's, cam timing, ignition timing, fuel, EGT's..... and I'll stop there. This must be done in 2 increments to determine best split and advance/retard at various boost levels(10, 15, 20psi) on a 240whp-350whp otherwise stock 1.8.

I'm serious!
There's plenty of posts re: cam timing results on teh dyno. Do a search of m.net in the power mods section.
Ben is offline   Reply With Quote
Old 07-07-2008, 01:12 PM   #39
Junior Member
iTrader: (7)
 
Join Date: Jun 2005
Location: Texas
Posts: 376
Total Cats: 16
Default

Quote:
Originally Posted by Ben View Post
There's plenty of posts re: cam timing results on teh dyno. Do a search of m.net in the power mods section.
Before doing the exhintake cam and trying to figure out what to degree it to I spent an embarrasing amount of time reading useless threads. Only one guy did a lot of playing with special grind cams and had little gain but he didn't publish good details, making me think that it wasn't tuned properly.

There are a million threads on how to cut the cam and how and where to drill the indexing hole on a stock gear.

The info on m.net doesn't apply to turbo applications. Well, I haven't done a search on cams there for almost two years so maybe there is new info there. I come here for info now!
dvcn is offline   Reply With Quote
Old 07-07-2008, 01:24 PM   #40
Ben
Supporting Vendor
iTrader: (33)
 
Ben's Avatar
 
Join Date: Jul 2006
Location: atlanta-ish
Posts: 12,689
Total Cats: 99
Default

sorry, you're right, I don't recall any exhaust swap & turbo specific threads. most of those cheap bastards are n/a and just drilled and set the exh cam in. but there are plenty of threads regarding adj cam gears and turbo regarding improvements seen on the dyno.
Ben is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
1994 Spec Miata Race Car SM/SM2/SSM For Sale Quinn Cars for sale/trade 6 10-23-2016 08:58 AM
New M62 Miata owner Pist0n Meet and Greet 4 10-01-2015 09:18 PM
3rd Time's a Charm...hopefully. zephyrusaurai Meet and Greet 2 09-28-2015 11:59 PM
VR6 to Miata Swap ScrapinMX5 Meet and Greet 8 09-28-2015 02:04 PM


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 11:45 PM.