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Hood dump pipe AFR reading

 
Old 12-05-2018, 06:36 PM
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Default Hood dump pipe AFR reading

Currently in the stage of researching turbo things for my 46k mile 1990 miata I have most parts sourced.
bosch ev14 550cc injectors
top mount cast manifold
china t3 50mm coldside 48mm hotside
MS pnp2
Tial 38mm ewg
intercooler with piping
oil lines
. . .
I plan on running a exhaust dump pipe out the hood.
Full exhaust would be nice moneys tight, maybe some of your inputs will change my mind for the better.

This is most likely a ridiculous question but serious.
Will the short dump pipe read afr's correctly or is it going to throw them off due to having a short dump pipe since Its a top mount so its going to have a short path of exhaust out the hood? Hopefully that made sense.
Plan on tapping the O2 sensor into the pipe at where it will bend x degrees upward for it to go out the hood. Leaving at least 6 inches plus to the atmosphere
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Old 12-05-2018, 06:56 PM
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stahp
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Old 12-05-2018, 07:11 PM
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Originally Posted by Jacobmx5_ View Post
Will the short dump pipe read afr's correctly or is it going to throw them off due to having a short dump pipe since Its a top mount so its going to have a short path of exhaust out the hood?
A sensor located six inches from the tip will yield inaccurate (false-lean) readings due to reversion, in a manner which will not be linearly consistent across any predictable map of RPM vs load.

This is why tailpipe sensors of the sort commonly seen in automotive emissions test stations and chassis dynos are located on the end of a long rod, and are generally shrouded.

Also, dumping exhaust out through the hood is just a terrible idea, generally. Especially if the vehicle is anything other than a drag-queen which gets trailed to events. (As you cite the cost of an exhaust system as a concern, I assume this not to be the case.)

Unsolicited advice: if spending $500 on an exhaust system is a major financial hardship for you, you're not going to like owning a turbocharged car long-term.
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Old 12-06-2018, 01:38 AM
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If breathing fumes, going deaf, and attracting the attention of every cop in a 3 mile radius is cool these days, then go for it.

you bought terrible parts, might as well have a terrible setup I guess.

and yes, your afr will not read correctly.
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Old 12-06-2018, 04:50 AM
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https://www.miataturbo.net/diy-turbo...5-video-98389/

Please see this for venting dump pipe through the hood.
TL;DR do not do it.
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Old 12-06-2018, 06:50 AM
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I rode in a shitbox with a hood dump and can tell you that driving it two blocks made my eyes water and I stunk like exhaust all day.

If you cannot afford a piece of exhaust pipe you cannot afford to own and operate a turbo Miata.

You don't have an upgraded clutch on your list in the stock clutch will only handle the stock power of a 1.6.

The 1.6 diffs fail at stock power levels so replacement 1.8 differentials and axles are required.

Since you have a 1.6 you also require a variable throttle position sensor which you will have to wire in or your car will run poorly everytime you stomp on the gas.

There's more but you probably don't want to hear it.
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Old 12-06-2018, 07:25 AM
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What Craigslist area will this thing be sold in? I need to keep other noobs away from it.
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Old 12-06-2018, 07:49 AM
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Hood dumps are stupid. Have some self respect, you can do better.
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Old 12-06-2018, 08:35 AM
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Originally Posted by borka View Post

you bought terrible parts, might as well have a terrible setup I guess.
Constructive criticism?
Why are the parts terrible?
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Old 12-06-2018, 08:57 AM
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Hood dumps are the new cancer of the car world. So ******* stupid.
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Old 12-06-2018, 09:01 AM
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Nothing says "class-less trash" like a hood dump.
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Old 12-06-2018, 09:16 AM
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Originally Posted by Jacobmx5_ View Post


Constructive criticism?
Why are the parts terrible?
top mount manifold without a matching downpipe, now you in a bind and cant afford to have a good custom downpipe welded up. Thus genius hood dump idea.

Ewg china turbo. Why not internal wastegate? Now you are stuck with the impossible mission and complication of the inability to make a normal downpipe, thus again forcing you into hood dump.

you save like $500 in buying **** parts vs a proper kraken manifold/Downpipe set. Is $500 worth it to have an obnoxiously loud and smelly setup? While butchering the car?

time and time again I see botched jobs just like this end up on craigslist, a week after the cool factor of hood exhaust wears off, and it becomes an obnoxious car to drive.

example



do you want to be cool like this?
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Old 12-06-2018, 11:42 AM
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Upon further investigation there shall be no dump pipe. Thanks for the inputs.
Does anybody know where i can Scavenge 3 inch exhaust piping.
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Old 12-06-2018, 11:46 AM
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yes
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Old 12-06-2018, 11:51 AM
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Originally Posted by 18psi View Post
yes
Me too.
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Old 12-06-2018, 12:30 PM
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I also know as well
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Old 12-06-2018, 12:32 PM
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I have purchased my fair share of 3" pipe in the past.
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Old 12-06-2018, 01:07 PM
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Originally Posted by concealer404 View Post
I have purchased my fair share of 3" pipe in the past.
but did you scavenge it?
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Old 12-06-2018, 01:17 PM
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he just bit the pillow and took it. allofit. like a man
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Old 12-06-2018, 01:19 PM
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I scavenged my bank account to get some.
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