Turbo gurus: need advice!!!

[97 Nightmare]

Ok so I'm at a dead point in my planning process. I've read and read and have decided the basics of my combo but I need some advice on some of the smaller pieces.

After talking with nasvt, he has lead me in the correct direction to what I should do to finish up my motor. And Zachary has given me great advice on my transmission and fuel system. So now I'm left with two minor questions.

I'm planning to get the on3 forward facing turbo kit but don't plan to use the turbo, wastegate, or blow off valve that come with it. I've decided to run a Precision 67mm billet wheel turbo with the .81 a/r housing. I plan to run high teens into low 20s on boost pressure. What are some good wastegates and blow off valves to accommodate that setup? Price isn't really an issue since I want to do this right. Thanks in advance.

Cory

 

[Nightmare302]

Ok so I'm at a dead point in my planning process. I've read and read and have decided the basics of my combo but I need some advice on some of the smaller pieces.

After talking with nasvt, he has lead me in the correct direction to what I should do to finish up my motor. And Zachary has given me great advice on my transmission and fuel system. So now I'm left with two minor questions.

I'm planning to get the on3 forward facing turbo kit but don't plan to use the turbo, wastegate, or blow off valve that come with it. I've decided to run a Precision 67mm billet wheel turbo with the .81 a/r housing. I plan to run high teens into low 20s on boost pressure. What are some good wastegates and blow off valves to accommodate that setup? Price isn't really an issue since I want to do this right. Thanks in advance.

Cory

If price is no issue why are you starting with on3? They are a great budget setup but you'd have better sucess with other kits more so if you are supplying your own turbo/wg/bv. I personally like JGS parts though.

 

[97 Nightmare]

Well it was between hellion and on3 that I actually knew of. And out of those two I'd have to change certain things about either one to be happy so I figured the on3 would be fine as it seems their piping is very nice. I'll search for JGS though. I've never heard of them.

Cory

 

[goats]

As for a wastegate I would use a tial
As for a blow off valve I would only use a synapse cause it's will never surge(the fluttering you would hear just driving it around) or leak. I ran one for years on a srt4 with a 50 trim on 25+psi and never a issue.I've used others but liked the synapse the best.

 

[F8L BYT]

Why a 67? That's a bit small especially with the amount of boost you are planning which means you have a built engine so why not a bigger more efficient turbo?

 

[97 Nightmare]

Any suggestions towards size of the blow off? I'm under the assumption that wastegates are just sprung to certain boost levels so size isn't an option on them. Right?

Cory

 

[goats]

Any suggestions towards size of the blow off? I'm under the assumption that wastegates are just sprung to certain boost levels so size isn't an option on them. Right?

Cory

Size does matter cause if it's to small it will lead to boost creap(acting like a centrifical supercharger). As for size I wouldn't run anything smaller than 44mm. Not all who are created equal.

 

[97 Nightmare]

Why a 67? That's a bit small especially with the amount of boost you are planning which means you have a built engine so why not a bigger more efficient turbo?

I don't wanna wait til 4000 rpms to hit full boost. I want some low end to occur but don't want to go with a twin screw head swap setup.

Cory

 

[97 Nightmare]

Size does matter cause if it's to small it will lead to boost creap(acting like a centrifical supercharger). As for size I wouldn't run anything smaller than 44mm. Not all who are created equal.

Good info. Thank you sir. Is there also a such thing as going too big?

Cory

 

[goats]

Good info. Thank you sir. Is there also a such thing as going too big?

Cory

not really

 

[crazycarlo]

try CG Fabrication. They make the hotside thats really high quality. Then you could buy a Ebay intercooler and coldside to make yourself. As for BOV and wastegates man any of the name brands will prob work. Tial, HKS, TurboXS. Id atleast go 70mm if I were you. If you dont wanna spend alot go on the turbo forums and look for a used Masterpower T-70.

 

[97 Nightmare]

try CG Fabrication. They make the hotside thats really high quality. Then you could buy a Ebay intercooler and coldside to make yourself. As for BOV and wastegates man any of the name brands will prob work. Tial, HKS, TurboXS. Id atleast go 70mm if I were you. If you dont wanna spend alot go on the turbo forums and look for a used Masterpower T-70.

Thanks for the advice. I'll definitely check out the CG stuff. And I'm wondering as far as the name brands go, how different is their sound on a v8 motor vs how different they sound on a 4 banger. One Mazda guy around here's car sounds like a squirrel. I hate that. Haha. And I'm pretty set on the Precision unit but if for some reason funds become restricted I suppose I could settle for a Masterpower. I just prefer new stuff so I don't have any doubts about my gear.

Cory

 

[F8L BYT]

I don't wanna wait til 4000 rpms to hit full boost. I want some low end to occur but don't want to go with a twin screw head swap setup.

Cory

I understand that. Build the engine for that, higher compression (9.5-10.0 is what I would suggest) and make sure the turbo you will be getting has a smaller A/R. That combination should make boost and power at a lower rpm and continue up and reach the goal you have in mind

 

[na svt]

I don't wanna wait til 4000 rpms to hit full boost. I want some low end to occur but don't want to go with a twin screw head swap setup. Cory

Poor cam timing is the reason 4v engines make no tq, require steep gears to be quick and spool turbos slowly.

With a stock runner length intake and proper cam timing you can get a 76mm turbo to spool quickly. They dyno sheet below shows what proper cam timing can do, the higher tq and mid range power translates to much quicker turbo spooling and better driveability which is needed with the turbo friendly highway gears. With low compression proper cam timing is even more critical.

The graph shows a stock Mach with 96-98 cobra intake cams (degreed and undegreed) and stock exhaust and intake manifolds.

 

[03bluemach]

67m with a .81AR ... with that AR an the goal u have it will start to choke .. i would think about doing 70m with a .96 AR .. Turbonetics makes a Hurricane series turbo that has 76m or 78m guts in a 67 housing that spool pretty fast i hear .. As far as a BOV a tial 50m should work fine ,you might have to change the spring depending on what vac ur engine see's

 

[03bluemach]

AS far as the on3 kit goes good luck if you still have ABS an AC thats all i'll say .If you want to know more PM me .. Been there done that thats why i went CG !!

 

[97 Nightmare]

Poor cam timing is the reason 4v engines make no tq, require steep gears to be quick and spool turbos slowly.

With a stock runner length intake and proper cam timing you can get a 76mm turbo to spool quickly. They dyno sheet below shows what proper cam timing can do, the higher tq and mid range power translates to much quicker turbo spooling and better driveability which is needed with the turbo friendly highway gears. With low compression proper cam timing is even more critical.

The graph shows a stock Mach with 96-98 cobra intake cams (degreed and undegreed) and stock exhaust and intake manifolds.

Yes Todd I was planning on doing the specs you gave me over the phone that evening we spoke as to cam timing. You also said I should be able to reach my goals with the 67mm. With proper cam timing, what will be the difference in lag between the 67 and the 76? I suppose it's not completely out of the picture to run a 76. That would give me room to grow as well.

Cory

 

[97 Nightmare]

AS far as the on3 kit goes good luck if you still have ABS an AC thats all i'll say .If you want to know more PM me .. Been there done that thats why i went CG !!

I looked at CG last night. Their stuff looks amazing. So that will more than likely be the route I will go. Which k member works best with them? It didn't specify on the website. My only concern is there are no shops local to here that I trust to fab up my cold side. I suppose I could ebay a cold side? Input is more than welcome. And I will definitely pm you.

Cory

 

[Mike@TF]

yeah you could do that..or just get a hellion cold side setup...and like stated go with a nice 76mm..with the right turbo and engine setup a 76mm will spool quick and can make some nasty power..

i have a comp turbo billet wheel,triple ball bearing, anti surge compressor housing 76mm thats brand new i will sell for $1800...its a $2400+ turbo.. im going to go with a comp turbo billet wheel 82mm..im greedy for more power and car not even together yet lmao..

 

[97 Nightmare]

yeah you could do that..or just get a hellion cold side setup...and like stated go with a nice 76mm..with the right turbo and engine setup a 76mm will spool quick and can make some nasty power..

i have a comp turbo billet wheel,triple ball bearing, anti surge compressor housing 76mm thats brand new i will sell for $1800...its a $2400+ turbo.. im going to go with a comp turbo billet wheel 82mm..im greedy for more power and car not even together yet lmao..

I'll keep you in mind on the turbo. And I was unaware that hellion just sold their cold side separate. That makes this alot easier if so. I'm going to look into that now. Thanks.

Cory