Suggestions on Turbo resizing invited... - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


DIY Turbo Discussion greddy on a 1.8? homebrew kit?

Reply
 
 
 
LinkBack Thread Tools
Old 01-24-2014, 03:46 PM   #1
Senior Member
Thread Starter
 
Join Date: Dec 2010
Location: Auckland, NZ
Posts: 782
Total Cats: 23
Default Suggestions on Turbo resizing invited...

My 1600 motor is running a T28 from a Nissan GTiR, this turbo appears to have a .86 hot side (i know nothing about all this coding etc except that .86 is probably too large for my motor).

At the dyno it couldn't achieve more than 14psi... in the interest of full disclosure we did have a "slight" hot side leak at amx boost but neither the dyno guy or I feel that was the issue....but we think it was probably more that the motor didn't have enough puff to push the turbo rather than a leak etc...

In addition my new long runner manifold seems to have exagerated the exisitng late boost issues (max around 4k) to the point where it is hard to drive and (I think) would be considerably quicker if it didn't hit full boost at 5k!!!

Having just spent considerable money on new manifold, inlet piping, IC etc I am reluctant to change the turbo out completely (if necessary I will next season when I have replenished funds) so am looking to the MT mafia for suggestions as to what I should be doing to get through this season....

Are there bolt on hot sides that are more effective for this motor? Should we be looking at cold side impellors...etc...(remember, cheapest solution possible to improve drivability till the end of the season...)
mx5-kiwi is offline   Reply With Quote
Old 01-24-2014, 04:13 PM   #2
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,174
Total Cats: 2,575
Default

Yes there are plenty of other turbos that would drop right in.

But before you go throwing money away why not diagnose and fix the issue? Your car should absolutely be able to hit more than 14psi on this turbo, and it should be able to spool it quicker than 5k. You obviously have a leak and/or other problems.
18psi is offline   Reply With Quote
Old 01-24-2014, 04:59 PM   #3
I'm Miserable!
iTrader: (11)
 
Join Date: Apr 2008
Location: Texas, 'Murica
Posts: 2,505
Total Cats: 7
Default

Quote:
Originally Posted by 18psi View Post
Yes there are plenty of other turbos that would drop right in.

But before you go throwing money away why not diagnose and fix the issue? Your car should absolutely be able to hit more than 14psi on this turbo, and it should be able to spool it quicker than 5k. You obviously have a leak and/or other problems.
This, find the boost leak.
chicksdigmiatas is offline   Reply With Quote
Old 01-24-2014, 05:05 PM   #4
Elite Member
iTrader: (17)
 
Join Date: Aug 2007
Location: Fort Myers, FL
Posts: 2,790
Total Cats: 128
Default

Probably a stupid question, but have you played with the adjustment on the wastegate actuator? I remember having issues with my gt2560 building boost slowly until I tightened it up a turn or 2 and it was like a completely different car.
pdexta is offline   Reply With Quote
Old 01-24-2014, 05:14 PM   #5
Senior Member
Thread Starter
 
Join Date: Dec 2010
Location: Auckland, NZ
Posts: 782
Total Cats: 23
Default

Quote:
Originally Posted by pdexta View Post
Probably a stupid question, but have you played with the adjustment on the wastegate actuator?
Thansk for the replies.

No questions are stupid to me, I came from bike racing so have ZERO knowledge or history of turbo setup....

What should we be looking for to adjust the wastegate actuator? Can you tell if it is mis adjusted....before playign with it, it would be nice to know if it was the cause of the high revs before boost...(this would really please my manifold guy!)
mx5-kiwi is offline   Reply With Quote
Old 01-24-2014, 05:51 PM   #6
Destroyer of Inconel
iTrader: (37)
 
EO2K's Avatar
 
Join Date: Apr 2010
Location: In ur driveway, abusin' ur WPA
Posts: 9,642
Total Cats: 954
Default

You said you swapped the exhaust housing on the turbo... is there any chance you used a housing for a turbo with a much larger turbine wheel? </pulledfromass>

Edit: That may have been someone in another thread? Not sure where I got that...
EO2K is offline   Reply With Quote
Old 01-24-2014, 06:12 PM   #7
Moderator
iTrader: (11)
 
sixshooter's Avatar
 
Join Date: Nov 2008
Location: Tampa, Florida
Posts: 15,654
Total Cats: 1,559
Default

Pull the E-clip and separate the actuator rod from the wastegate lever. Then make sure the rod causes the lever to fully close the wastegate. You may spin the end of the wastegate rod fitting a few turns if necessary to preload the wastegate arm to hold the wastegate closed a bit more tightly.

Exhaust leaks between the head and the turbo work just like an open wastegate and will kill boost and spool.

Boost leaks on the fresh air side will kill boost.
sixshooter is online now   Reply With Quote
Old 01-25-2014, 09:51 PM   #8
Elite Member
iTrader: (1)
 
Leafy's Avatar
 
Join Date: Jun 2012
Location: NH
Posts: 9,091
Total Cats: 90
Default

Sounds like a hotside leak or mis adjusted iwga. Or completely garbage tune thats way to rich and with no spark advance.
Leafy is offline   Reply With Quote
Old 08-19-2014, 09:27 PM   #9
Senior Member
Thread Starter
 
Join Date: Dec 2010
Location: Auckland, NZ
Posts: 782
Total Cats: 23
Default

Just to come back to this thread we have gone to a .42 (?) hot side and made massive amounts more torque at 3k (went from 80 to 175) and gained about 15 HP on top. Car was fast before (with no torque) should be amazing now.....

265HP at the wheels with 14/15 PSI boost...all at much lower revs than before...motor should appreciate that...
mx5-kiwi is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Project Gemini - Turbo Civic on the Cheap Full_Tilt_Boogie Build Threads 57 07-19-2017 05:11 PM
WTB MP62 (Hotside) (NB2) Rick02R WTB 3 01-03-2016 08:18 PM
Expected intake temps on the track? tazswing Race Prep 20 10-03-2015 12:04 PM
ISO 1.6 turbo cast iron manifold cale saurage DIY Turbo Discussion 16 10-01-2015 12:25 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 08:42 AM.