Goodspeed 2008 STI GT35R Twinscroll build

08stiGS35R · 03-28-2009, 06:06 PM

Goodspeed's New GT35R twin-scroll kit for my 2008 STI will begin on Monday (3/30) and I wanted to share some preliminary info. The turbo is a GT35R twin scroll- .78 A/R, 64mm 84 trim with twin wastegates. This is a custom setup that Goodspeed developed. Here the projected mod list for this kit:

Goodspeed GT35R w/twin wastegate setup
Goodspeed FMIC
850CC injectors
255lph Walbro feul pump
Goodspeed Speed density air intake
Downpipe/Upipe
One level down colder sparkplugs - not sure what brand or gap yet.

Pics will arrive after the build has made some good progression.

Current mods are:

Cobb AP with Stage 1 AZ91 Map.
Cobb SSK
Cobb Turbo heat shield
Cobb front and rear sway bar kit
Cobb Sport springs
Invidia Q300 exhaust
Whiteline rear suspension bushings
Kartboy Front Endlinks
Whiteline steering rack bushings
Motul fluids for engine, diff, and transmission

Contact GoodSpeed Performance Lab @ 480.747.6150 for pricing.

I got this part of this excerpt from Captain Inferno's thread on NASIOC:

""Quoted from there web site" Our goal: To provide our customers a no-compromise, completely streetable turbo kit. One with extremely fast spool and a smooth power band, while still providing massive HP and torque potential. A step closer to having your cake and eating it to! For this reason we have chosen our own GT35 twin scroll configuration using a fully divided header and custom up pipe. The separate waist gates can be plumed back into the exhaust for a stealth street setup or dump for race applications."

Our goal is to make about 400WHP on 91pump since I am still on the stock block and clutch. Dont want to push it over that since I cant afford a new motor right now. I do have plans in about 1 year or so to possibly upgrade to either a new shortblock or build the motor up to run boost. I know this kit is not even close to hitting its peak on the stock block but this is my plan to upgrade slowly and enjoy each phase.

My car has about 6100 miles now and I just completed a leakdown and compression test at Goodspeed. Results are:

Compression 130, 130, 130, 130
Leakdown 4%, 4%, 4%, 4%

Motor is pretty tight so I am pretty confident that it should hold that power for a little while.......

Here are a few pics of the ride and the suspension work.
http://flickr.com/gp/34691491@N05/7kT0c7
http://flickr.com/gp/34691491@N05/6Gs6EX
http://flickr.com/gp/34691491@N05/U41594
http://flickr.com/gp/34691491@N05/Ho2S80
http://flickr.com/gp/34691491@N05/D65M33
http://flickr.com/gp/34691491@N05/51VzeW
http://flickr.com/gp/34691491@N05/e8c3Wa

* Registered users of the site do not see these ads.

onlyTurbo · 03-28-2009, 11:09 PM

Quote:

Originally Posted by 08stiGS35R

Goodspeed's New GT35R twin-scroll kit for my 2008 STI will begin on Monday (3/30) and I wanted to share some preliminary info. The turbo is a GT35R twin scroll- .78 A/R, 64mm 84 trim with twin wastegates. This is a custom setup that Goodspeed developed. Here the projected mod list for this kit:

Goodspeed GT35R w/twin wastegate setup
Goodspeed FMIC
850CC injectors
255lph Walbro feul pump
Goodspeed Speed density air intake
Downpipe/Upipe
One level down colder sparkplugs - not sure what brand or gap yet.

Pics will arrive after the build has made some good progression.

Current mods are:

Cobb AP with Stage 1 AZ91 Map.
Cobb SSK
Cobb Turbo heat shield
Cobb front and rear sway bar kit
Cobb Sport springs
Invidia Q300 exhaust
Whiteline rear suspension bushings
Kartboy Front Endlinks
Whiteline steering rack bushings
Motul fluids for engine, diff, and transmission

Contact GoodSpeed Performance Lab @ 480.747.6150 for pricing.

I got this part of this excerpt from Captain Inferno's thread on NASIOC:

""Quoted from there web site" Our goal: To provide our customers a no-compromise, completely streetable turbo kit. One with extremely fast spool and a smooth power band, while still providing massive HP and torque potential. A step closer to having your cake and eating it to! For this reason we have chosen our own GT35 twin scroll configuration using a fully divided header and custom up pipe. The separate waist gates can be plumed back into the exhaust for a stealth street setup or dump for race applications."

Our goal is to make about 400WHP on 91pump since I am still on the stock block and clutch. Dont want to push it over that since I cant afford a new motor right now. I do have plans in about 1 year or so to possibly upgrade to either a new shortblock or build the motor up to run boost. I know this kit is not even close to hitting its peak on the stock block but this is my plan to upgrade slowly and enjoy each phase.

My car has about 6100 miles now and I just completed a leakdown and compression test at Goodspeed. Results are:

Compression 130, 130, 130, 130
Leakdown 4%, 4%, 4%, 4%

Motor is pretty tight so I am pretty confident that it should hold that power for a little while.......

Here are a few pics of the ride and the suspension work.
http://flickr.com/gp/34691491@N05/7kT0c7
http://flickr.com/gp/34691491@N05/6Gs6EX
http://flickr.com/gp/34691491@N05/U41594
http://flickr.com/gp/34691491@N05/Ho2S80
http://flickr.com/gp/34691491@N05/D65M33
http://flickr.com/gp/34691491@N05/51VzeW
http://flickr.com/gp/34691491@N05/e8c3Wa

Nice car... What power are you expecting to get after all mods? What are you expecting to do with so much power?

blowbyu24 · 03-29-2009, 11:01 AM

Quote:

Originally Posted by 08stiGS35R

The turbo is a GT35R twin scroll- .78 A/R, 64mm 84 trim with twin wastegates.

i will have more proof in about a week or so, with more dyno results, but i am really starting to believe that the twin scroll turbos start to stand out with the larger a/r. I was tuned with the .85 a/r on the 40r and power was a little lower than expected...since then i have put in a 1.06a/r and the spool is actually better than the .85, i think the .85 was just too restrictive with my custom UR header...i think it should be something to reconsider (the.78 a/r, go with a larger a/r) that’s my .02 best of luck!

scby rex · 03-29-2009, 11:31 AM

Thanks onlyturbo for reposting the first post in the second post. I dont think I read it the first time.

That muffler is ugly as sin with the pipe going straight in from the bottom. I think it will have clearance issues for some people.

carnz-pj-410 · 03-29-2009, 11:37 AM

130 compression is pretty low. the lowest end of the spec in the service manual is 142psi.

sponaugle · 03-29-2009, 01:13 PM

Quote:

Originally Posted by carnz-pj-410

130 compression is pretty low. the lowest end of the spec in the service manual is 142psi.

The are three potential other causes for consistant lower readings like that:

(1) A Built motor with loose tolerances (my CP piston block with 4 thou measured at about 130)

(2) Low temperatures

(3) Low cranking RPM from having battery in the trunk, or using jumper cords to jump from the battery to the car due to removing the battery to get to the spark plugs.

Jeff

CovertPerformance · 03-29-2009, 01:37 PM

Or a gauge that is off

08stiGS35R · 03-29-2009, 02:40 PM

Quote:

Originally Posted by sponaugle

The are three potential other causes for consistant lower readings like that:

(1) A Built motor with loose tolerances (my CP piston block with 4 thou measured at about 130) - No. Stock motor.

(2) Low temperatures - Not too low, maybe 55 degrees

(3) Low cranking RPM from having battery in the trunk, or using jumper cords to jump from the battery to the car due to removing the battery to get to the spark plugs. - We were using a portable battery since the main battery was removed.
Jeff

See responses in blue.

08stiGS35R · 03-29-2009, 02:42 PM

Quote:

Originally Posted by onlyTurbo

Nice car... What power are you expecting to get after all mods? What are you expecting to do with so much power?

If you mean after the built motor, I am looking to have a solid mid-low 10sec 1/4 car.

carnz-pj-410 · 03-29-2009, 03:31 PM

Quote:

Originally Posted by sponaugle

The are three potential other causes for consistant lower readings like that:

(1) A Built motor with loose tolerances (my CP piston block with 4 thou measured at about 130)

(2) Low temperatures

(3) Low cranking RPM from having battery in the trunk, or using jumper cords to jump from the battery to the car due to removing the battery to get to the spark plugs.

Jeff

ah ok good to know, i didnt see built motor listed on there so i figured id mention it to see if the OP was aware

az03wrx · 03-29-2009, 04:05 PM

I was just talking to Jon about this yesterday. Can't wait to see how it turns out and what numbers it puts down.

NAZSTI · 03-29-2009, 04:41 PM

Congrats man on your setup. Joe and Jon are top notch at what they do, Joe built my 04 STi back in 04 and I'm very very happy with what I have. Post up some pics when the job is done.

Thanks
Rick

sabreofsd · 03-31-2009, 10:42 AM

Subb'ed, I'm interesting in the spool and power this makes!

08stiGS35R · 03-31-2009, 10:07 PM

Quote:

Originally Posted by blowbyu24

i will have more proof in about a week or so, with more dyno results, but i am really starting to believe that the twin scroll turbos start to stand out with the larger a/r. I was tuned with the .85 a/r on the 40r and power was a little lower than expected...since then i have put in a 1.06a/r and the spool is actually better than the .85, i think the .85 was just too restrictive with my custom UR header...i think it should be something to reconsider (the.78 a/r, go with a larger a/r) that’s my .02 best of luck!

Quote:

Originally Posted by NAZSTI

Congrats man on your setup. Joe and Jon are top notch at what they do, Joe built my 04 STi back in 04 and I'm very very happy with what I have. Post up some pics when the job is done.

Thanks
Rick

Quote:

Originally Posted by chump

I was just talking to Jon about this yesterday. Can't wait to see how it turns out and what numbers it puts down.

Quote:

Originally Posted by sabreofsd

Subb'ed, I'm interesting in the spool and power this makes!

Thanks everyone. I cant wait for the first dyno run

.

Latest update, car is torn down and the build up has begun

. This will take several weeks since the FMIC and Intake is brand new to the 08 and will need to designed and fitted. Will post pics when they become available.

ChandlerWRX06 · 03-31-2009, 11:11 PM

I dyno'd my car at Goodspeed today. .

the Sti is going to be a BEAST. Jon is hard at work haha

barely even said hi lol

08stiGS35R · 04-05-2009, 02:47 PM

http://flickr.com/gp/34691491@N05/74yNHn

http://flickr.com/gp/34691491@N05/F5521p

Here are 2 sneak pics of the project. Jon has been hard at work the last 4 days.

Yes, that is a 4inch intake with a massive air filter.

deathinacan · 04-05-2009, 04:48 PM

Good luck with the build -

I built nearly the same kit, albiet with a built block and Jun head/valvetrain w/ kelford cams...

You're going to see how quickly your fuel cuts you short of your HP goals past 400whp with the 255lph - I had to upgrade to a Automotive 250GPH fuel pump w/ pressure regulator and 1000cc injectors to crest over the 500 whp mark... after that though, fuel issues weren't much of a problem...

I'm sure you're already trackin that, but ay, its worth a mention. Granted the dyno I was on was incredibly low reading, so who knows what the actual numbers were...

I'll be looking forward to seeing what the results are on the stock block... the built block SCREAMS with that setup... I'm using a single wastegate however, divorced from the up-pipe(s) at an equal length. I couldnt find the room to fit two wastegates in there, but I suppose it can be done in such a slim location(aps did it, and you're doing it as well - congrats!).

difference between the normal 35/40r (.78a/r atp turbo) and the conventional 35r is pretty substantial when it comes to spooling at lower RPM's.

You're going to have a fun time with your setup.

pm me for pics/ideas if you run into any problems.

kor

08stiGS35R · 04-05-2009, 06:48 PM

Quote:

Originally Posted by deathinacan

Good luck with the build -

I built nearly the same kit, albiet with a built block and Jun head/valvetrain w/ kelford cams...

You're going to see how quickly your fuel cuts you short of your HP goals past 400whp with the 255lph - I had to upgrade to a Automotive 250GPH fuel pump w/ pressure regulator and 1000cc injectors to crest over the 500 whp mark... after that though, fuel issues weren't much of a problem...

I'm sure you're already trackin that, but ay, its worth a mention. Granted the dyno I was on was incredibly low reading, so who knows what the actual numbers were...

I'll be looking forward to seeing what the results are on the stock block... the built block SCREAMS with that setup... I'm using a single wastegate however, divorced from the up-pipe(s) at an equal length. I couldnt find the room to fit two wastegates in there, but I suppose it can be done in such a slim location(aps did it, and you're doing it as well - congrats!).

difference between the normal 35/40r (.78a/r atp turbo) and the conventional 35r is pretty substantial when it comes to spooling at lower RPM's.

You're going to have a fun time with your setup.

pm me for pics/ideas if you run into any problems.

kor

Thanks Man! My plan is definitely to use the stock block for a while and save up for a new built block later.

jaxscuby · 04-06-2009, 06:21 AM

please use forged after market pistons..
or you'll be replacing them..

CAPTIN INFERNO · 04-06-2009, 09:38 AM

Quote:

Originally Posted by 08stiGS35R

http://flickr.com/gp/34691491@N05/74yNHn

http://flickr.com/gp/34691491@N05/F5521p

Here are 2 sneak pics of the project. Jon has been hard at work the last 4 days.

Yes, that is a 4inch intake with a massive air filter.

Looks good, I cant wait to some more pics and some vids.

CAPTIN INFERNO · 04-08-2009, 10:05 AM

I stopped by Goodspeed and saw your car.... WOW that looks SICK! Congrats. I cant wait to see that thing tear'en it up. Looks awsome man, hats of to the guys at Goodspeed.

08stiGS35R · 04-08-2009, 10:10 PM

Quote:

Originally Posted by CAPTIN INFERNO

I stopped by Goodspeed and saw your car.... WOW that looks SICK! Congrats. I cant wait to see that thing tear'en it up. Looks awsome man, hats of to the guys at Goodspeed.

Thanks Man! I plan on stopping by Friday to check out all of the changes. I just got done talking with Joe to see if I can post more sneak pics. They are making incredible progress.

Hats off too to Jon and Joe at Goodspeed.

Clark Turner · 04-09-2009, 12:00 PM

You should see this thing now! THat True 4 inch intake and 4 inch downpipe is just sick. Jon is doing some great fab work!

Clark

Phatron · 04-09-2009, 12:38 PM

is this car gonna run a maf still? didnt see it in the intake anywhere....

08stiGS35R · 04-09-2009, 01:58 PM

Quote:

Originally Posted by Phatron

is this car gonna run a maf still? didnt see it in the intake anywhere....

No MAF. Speed Density.

03-28-2009, 06:06 PM	#1
08stiGS35R Scooby Newbie Member#: 193165 Join Date: Oct 2008 Vehicle: 2008 Subaru STI SS	Goodspeed 2008 STI GT35R Twinscroll build Goodspeed's New GT35R twin-scroll kit for my 2008 STI will begin on Monday (3/30) and I wanted to share some preliminary info. The turbo is a GT35R twin scroll- .78 A/R, 64mm 84 trim with twin wastegates. This is a custom setup that Goodspeed developed. Here the projected mod list for this kit: Goodspeed GT35R w/twin wastegate setup Goodspeed FMIC 850CC injectors 255lph Walbro feul pump Goodspeed Speed density air intake Downpipe/Upipe One level down colder sparkplugs - not sure what brand or gap yet. Pics will arrive after the build has made some good progression. Current mods are: Cobb AP with Stage 1 AZ91 Map. Cobb SSK Cobb Turbo heat shield Cobb front and rear sway bar kit Cobb Sport springs Invidia Q300 exhaust Whiteline rear suspension bushings Kartboy Front Endlinks Whiteline steering rack bushings Motul fluids for engine, diff, and transmission Contact GoodSpeed Performance Lab @ 480.747.6150 for pricing. I got this part of this excerpt from Captain Inferno's thread on NASIOC: ""Quoted from there web site" Our goal: To provide our customers a no-compromise, completely streetable turbo kit. One with extremely fast spool and a smooth power band, while still providing massive HP and torque potential. A step closer to having your cake and eating it to! For this reason we have chosen our own GT35 twin scroll configuration using a fully divided header and custom up pipe. The separate waist gates can be plumed back into the exhaust for a stealth street setup or dump for race applications." Our goal is to make about 400WHP on 91pump since I am still on the stock block and clutch. Dont want to push it over that since I cant afford a new motor right now. I do have plans in about 1 year or so to possibly upgrade to either a new shortblock or build the motor up to run boost. I know this kit is not even close to hitting its peak on the stock block but this is my plan to upgrade slowly and enjoy each phase. My car has about 6100 miles now and I just completed a leakdown and compression test at Goodspeed. Results are: Compression 130, 130, 130, 130 Leakdown 4%, 4%, 4%, 4% Motor is pretty tight so I am pretty confident that it should hold that power for a little while....... Here are a few pics of the ride and the suspension work. http://flickr.com/gp/34691491@N05/7kT0c7 http://flickr.com/gp/34691491@N05/6Gs6EX http://flickr.com/gp/34691491@N05/U41594 http://flickr.com/gp/34691491@N05/Ho2S80 http://flickr.com/gp/34691491@N05/D65M33 http://flickr.com/gp/34691491@N05/51VzeW http://flickr.com/gp/34691491@N05/e8c3Wa * Registered users of the site do not see these ads.

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03-29-2009, 11:31 AM	#4
scby rex Scooby Guru Member#: 104878 Join Date: Jan 2006 Chapter/Region: TXIC Location: copperas cove Vehicle: 02 wrxbastardchild aw, 1,000,000 whp 2 aw tq	Thanks onlyturbo for reposting the first post in the second post. I dont think I read it the first time. That muffler is ugly as sin with the pipe going straight in from the bottom. I think it will have clearance issues for some people.

03-29-2009, 11:37 AM	#5
carnz-pj-410 Scooby Specialist Member#: 110994 Join Date: Mar 2006 Chapter/Region: MAIC Location: BALTIMORE Vehicle: 2004 WRX STi something good on the way	130 compression is pretty low. the lowest end of the spec in the service manual is 142psi.

03-29-2009, 01:37 PM	#7
CovertPerformance Vendor Member#: 196004 Join Date: Nov 2008 Chapter/Region: BAIC Location: Roseville, CA Vehicle: 06 STI OBP	Or a gauge that is off

03-29-2009, 04:05 PM	#11
az03wrx Scooby Specialist Member#: 106220 Join Date: Jan 2006 Chapter/Region: SWIC	I was just talking to Jon about this yesterday. Can't wait to see how it turns out and what numbers it puts down.

03-29-2009, 04:41 PM	#12
NAZSTI Scooby Specialist Member#: 164516 Join Date: Nov 2007 Chapter/Region: SWIC Location: Northern AZ STI hence username Vehicle: 2004 STI PSM	Congrats man on your setup. Joe and Jon are top notch at what they do, Joe built my 04 STi back in 04 and I'm very very happy with what I have. Post up some pics when the job is done. Thanks Rick

03-31-2009, 10:42 AM	#13
sabreofsd Scooby Specialist Member#: 48943 Join Date: Nov 2003 Chapter/Region: MAIC Location: NoVA Vehicle: 2004 95%*STi Blu/Gld www.dcawd.com	Subb'ed, I'm interesting in the spool and power this makes!

03-31-2009, 11:11 PM	#15
ChandlerWRX06 Scooby Specialist Member#: 184206 Join Date: Jul 2008 Chapter/Region: SWIC Location: Fliessem, Germany Vehicle: 2013 X1 sDrive 28i gray	I dyno'd my car at Goodspeed today. . the Sti is going to be a BEAST. Jon is hard at work haha barely even said hi lol

04-05-2009, 02:47 PM	#16
08stiGS35R Scooby Newbie Member#: 193165 Join Date: Oct 2008 Vehicle: 2008 Subaru STI SS	http://flickr.com/gp/34691491@N05/74yNHn http://flickr.com/gp/34691491@N05/F5521p Here are 2 sneak pics of the project. Jon has been hard at work the last 4 days. Yes, that is a 4inch intake with a massive air filter.

04-05-2009, 04:48 PM	#17
deathinacan Scooby Specialist Member#: 76826 Join Date: Dec 2004 Chapter/Region: NWIC Location: washington Vehicle: 2013 delorean P.I.T.A. to clean silver	Good luck with the build - I built nearly the same kit, albiet with a built block and Jun head/valvetrain w/ kelford cams... You're going to see how quickly your fuel cuts you short of your HP goals past 400whp with the 255lph - I had to upgrade to a Automotive 250GPH fuel pump w/ pressure regulator and 1000cc injectors to crest over the 500 whp mark... after that though, fuel issues weren't much of a problem... I'm sure you're already trackin that, but ay, its worth a mention. Granted the dyno I was on was incredibly low reading, so who knows what the actual numbers were... I'll be looking forward to seeing what the results are on the stock block... the built block SCREAMS with that setup... I'm using a single wastegate however, divorced from the up-pipe(s) at an equal length. I couldnt find the room to fit two wastegates in there, but I suppose it can be done in such a slim location(aps did it, and you're doing it as well - congrats!). difference between the normal 35/40r (.78a/r atp turbo) and the conventional 35r is pretty substantial when it comes to spooling at lower RPM's. You're going to have a fun time with your setup. pm me for pics/ideas if you run into any problems. kor

04-06-2009, 06:21 AM	#19
jaxscuby n00b Moderator Moderator Member#: 10613 Join Date: Sep 2001 Chapter/Region: South East Location: F L O R I D A Vehicle: 2002 USDM WRX WRB	please use forged after market pistons.. or you'll be replacing them..

04-08-2009, 10:05 AM	#21
CAPTIN INFERNO Scooby Specialist Member#: 74324 Join Date: Nov 2004 Chapter/Region: SWIC Location: AZ,NV,ND,CA & Rocky Point!! Vehicle: 04 GT40R/623WHP GSXR1216, TJ runnin 40's	I stopped by Goodspeed and saw your car.... WOW that looks SICK! Congrats. I cant wait to see that thing tear'en it up. Looks awsome man, hats of to the guys at Goodspeed.

04-09-2009, 12:00 PM	#23
Clark Turner NASIOC Vendor Member#: 178047 Join Date: Apr 2008 Chapter/Region: SWIC Location: AZ/Vegas Vehicle: 02 WRX STI Spec C Black	You should see this thing now! THat True 4 inch intake and 4 inch downpipe is just sick. Jon is doing some great fab work! Clark

04-09-2009, 12:38 PM	#24
Phatron Scooby Guru Member#: 36033 Join Date: Apr 2003 Chapter/Region: SCIC Location: Tuning Lab Vehicle: CEO PhatBottiTuning 2006 STi GTX3582 + Meth	is this car gonna run a maf still? didnt see it in the intake anywhere....