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View Full Version : Which Primary turbo should i use???



rfrbwags
02-12-2010, 12:28 AM
Hi all,i have a 98 GTB Limited with the EJ20R motor,57000km.
No mods (intentionally) besides a new 5 wire earthing kit,inner guard air box removed and hks panel filter.
I love the car as is but want some more punch from primary turbo,it currently running vf17p/vf18s
and was wanting to know a good primary upgrade as the vf17 is a little restrictive for my liking!
Also if can the VOD be reduced through changing the vacuum setup? (something i think iv heard)
Any help will be much appreciated.
Chris

Robbks
02-15-2010, 10:44 PM
VF17..??
96 GT-B should be VF18(pri) VF19(sec)

to get the things to spool and operate nicely there's a number of well documented mods to get things happening
1) free-flowing dump-pipes (3" primary, 2.5" secondary)
2) free-flowing exhaust 3"
3) port the primary (only on GTB) wastegate to allow it to flow more air for better boost control
4) port and match the ECV (allow ~1mm material left to seal it off properly)
5) port/ match the up-pipes with the exhaust housing
6) replace the small, crappy plastic turbo outlet pipes with larger silicone ones for better flow
7) you can adjust the ECV rod so that it opens slightly earlier to aid preperatory rotation which helps to lessen the VOD

ECV rod adjusting procedure
remove secondary heat-shield to gain access to the ECV rod

-have the car at operating temp
-start the car and let it idle
-lengthen the ECV rod (undo two locknuts first) until you hear it rattle
-tighten the rod approximately 1-2 turns.
-test to see when the ECV begins to open (hook up a boost gauge to the line that feeds the 'U' shaped plastic bit near the secondary BOV)
-you should notice a more smoother transition and higher boost level through the VOD
-each car will be different, just experiment until it feels right
** Doing this can cause a longer delay when switching from twin->single range, you just need to experiment to get a good balance

Canuck 2.5GT
02-18-2010, 11:19 AM
How about a 1994 GT BG5 with the EJ20H? Same mods apply? I have slightly increased boost, and a 3" Catback, intake silencer removed. Looking to get custom dump pipes fabbed up as well. Which turbos should I go with?

Robbks
02-18-2010, 06:00 PM
do all of the above mentioned mods to any TT.

anything bigger is an improvement for the asthmatic EJ20H
a pair of VF18/19's from a gen2 GTB, are a good upgrade (same as i have fitted to my EJ20R)
Or VF25/27 from the gen3 GTB's

Telemekas
02-22-2010, 07:57 AM
Primary turbo VF25 or better still the BB VF31
Refurbish your solenoid box at the same time
http://www.uklegacy.com/forums/index.ph ... ntry302591 (http://www.uklegacy.com/forums/index.php?showtopic=100528&pid=302591&st=0&#entry302591)

rfrbwags
03-24-2010, 04:22 AM
Thanks heaps for all your words of wisdom guys!!! much appreciated

Kilroy
05-05-2010, 12:49 PM
do all of the above mentioned mods to any TT.

anything bigger is an improvement for the asthmatic EJ20H
a pair of VF18/19's from a gen2 GTB, are a good upgrade (same as i have fitted to my EJ20R)
Or VF25/27 from the gen3 GTB's

Are all of these turbos straight bolt-ons? No mods necessary to get them to fit?

Kilroy
05-05-2010, 12:53 PM
VF17..??
96 GT-B should be VF18(pri) VF19(sec)

to get the things to spool and operate nicely there's a number of well documented mods to get things happening
1) free-flowing dump-pipes (3" primary, 2.5" secondary)
2) free-flowing exhaust 3"
3) port the primary (only on GTB) wastegate to allow it to flow more air for better boost control
4) port and match the ECV (allow ~1mm material left to seal it off properly)
5) port/ match the up-pipes with the exhaust housing
6) replace the small, crappy plastic turbo outlet pipes with larger silicone ones for better flow
7) you can adjust the ECV rod so that it opens slightly earlier to aid preperatory rotation which helps to lessen the VOD

ECV rod adjusting procedure
remove secondary heat-shield to gain access to the ECV rod

-have the car at operating temp
-start the car and let it idle
-lengthen the ECV rod (undo two locknuts first) until you hear it rattle
-tighten the rod approximately 1-2 turns.
-test to see when the ECV begins to open (hook up a boost gauge to the line that feeds the 'U' shaped plastic bit near the secondary BOV)
-you should notice a more smoother transition and higher boost level through the VOD
-each car will be different, just experiment until it feels right
** Doing this can cause a longer delay when switching from twin->single range, you just need to experiment to get a good balance

The rep at H&S Exhaust told me that the primary should be restricted to 2.5" and the secondary at 3".

Robbks
05-06-2010, 07:38 PM
Are all of these turbos straight bolt-ons? No mods necessary to get them to fit?
Yep, straight bolt-on.

there is one primary turbo that has a larger inlet, VF33 i think?? (i can;t remember) but it's only found on the AUDM B4.


The rep at H&S Exhaust told me that the primary should be restricted to 2.5" and the secondary at 3".

You're correct, my post is wrong
to confirm my car has 2.5" primary dump with a divorced wastegate (re-joins the dump as the pipe bends back under the car near the cross-member)
and 3" secondary dump

Made by these guys here in Oz
http://www.amauto.com.au/gallerystainless.html

Primary Dump pipe
http://www.amauto.com.au/img/TTDumps%20003.jpg
http://www.amauto.com.au/img/TTDumps%20001.jpg

Both Dumps
http://www.amauto.com.au/img/TTDumps%20005.jpg

Airgne
09-06-2010, 09:57 AM
so do these guys make dump pipes that mate up to the stock exhaust routing? also will they work on a 3rd gen. might get a 3rd gen for now until i get more money. no reuben i will not convert the ej208 into a single.

Reuben
09-06-2010, 12:28 PM
Hello fellow kiwi and limited owner ;) I have another suggestion. For less than $1000, a weekends spanner work, and some skinned knuckles, you can do this:

https://sl-i.net/FORUM/images/imported/2010/09/IMG_5600-1.jpg

https://sl-i.net/FORUM/images/imported/2010/09/IMG_5643-1.jpg

https://sl-i.net/FORUM/images/imported/2010/09/IMG_5930-1.jpg

https://sl-i.net/FORUM/images/imported/2010/09/IMG_5952-1.jpg




Single turbo for the win. Add some attention to detail and meticulous part collecting, you can get an engine bay like mine (the above is my mates limited)



https://sl-i.net/FORUM/images/imported/2010/07/IMG_5726-1.jpg

https://sl-i.net/FORUM/images/imported/2010/07/IMG_5728-1.jpg

Kilroy
09-07-2010, 09:49 AM
I went with downpipes from Hayward & Scott. Full stainless steel and after a heat wrap they mounted perfectly. Even with the overseas shipping price they were cheaper than I could find locally and I had the peace of mind knowing they would fit properly.

https://sl-i.net/FORUM/images/imported/2010/09/HS20Downpipes20017-1.jpg

Airgne
09-07-2010, 04:47 PM
how much did it cost in all? is this only for a 2nd gen twin turbo? do they make them for a 3rd gen?

also can you size down the picture. thanks

Airgne
09-07-2010, 05:14 PM
found them on the net. i see that they will work, but damn they are expensive.

Kilroy
09-07-2010, 05:16 PM
~$900CAN including shipping to my door in Canada. Cheapest I could source locally was $1200 as it was all custom fit and nobody had done one before. A couple of the shops even told me that 3" wouldn't fit.

Reuben
09-07-2010, 11:48 PM
3" lol. Has nobody told you about the overspool issues TT's get? aftermarket downpipe are renown here for blowing VF13's to bits.

A VF18 or 26 should be able to handle it though.

Kilroy
09-08-2010, 01:54 AM
Take another look at the pipes. That's why H&S makes them with a 2.5" restriction on the primary turbo.

Reuben
09-08-2010, 11:22 AM
True true.

Airgne
09-11-2010, 12:44 AM
what would be an upgrade turbo for the tt 3rd gens?

Robbks
09-12-2010, 08:18 PM
depends what you currently already have?

you probably have VF26/27 (or 25/27)
the AUDM B4 had the VF32/33 as did some of the JDM B4 RSK's i think.
they're as big as you get from the factory.

then you could look at having TD04/ TF035 internals hybridised into the VF housings,
endless options with enough money/ time

Reuben
09-20-2010, 07:50 PM
Upgrade for TT 3rd gen? There is none. If it's pre face lift, single convert, if it's post face lift, get the ECU tuned.