How much boost can I run with T28's, 555's and big coolers with stock internals?

 

Am I right in thinking that these turbos will be pushing far more air through for the same pressure so the usual maximum of about 16psi would actually be too much?

 

If so, how do I gauge how much is too much for my engine?

 

Chris.

How much boost can I run with T28's, 555's and big coolers with stock internals?

 

Am I right in thinking that these turbos will be pushing far more air through for the same pressure so the usual maximum of about 16psi would actually be too much?

 

If so, how do I gauge how much is too much for my engine?

 

Chris.

 

Chris did you have any internal work done when your engine was out???

Chris did you have any internal work done when your engine was out???

 

No that's why it says stock internals :rofl:

 

Hopefully the old engine will be getting forged pistons etc next year when the bank manager will talk to me again :cry:

 

Here's the engine spec:

 

T28's

Nismo 555's

SE Big Intercoolers

Doolz Twin POP, Single MAF

Turbo XS RFL Blow Off Valves

Polished & Ported stock manifolds

HKS Iridium Plugs

Howe Racing Radiator

Underdrive Pulley

2.5" straight through exhaust

Blitz SBC-iD & Power Meter.

Fidanza Flywheel

 

Removed:

AIV's

PRVR

EGR

Carbon Canister

No that's why it says stock internals :rofl:

 

Hopefully the old engine will be getting forged pistons etc next year when the bank manager will talk to me again :cry:

 

that will teach me not to read the thread properly :slap: :p

 

you realise this is going to turn in to a how much stock internals can handle debate don't you ;) :p

that will teach me not to read the thread properly :slap: :p

 

you realise this is going to turn in to a how much stock internals can handle debate don't you ;) :p

 

There's no debate, I know they're good for 1847BHP but it's just the amount of boost I'm unsure of :tongue:

 

I know that this setup should allow me to run about 17psi if that was the stock turbos but I'm sure 17psi on T28's would blow it apart?

 

Am I best booking it in for a proper mapping and dyno run to get some test results?

 

If I could get near 450+bhp I'd be very happy but I really just want to use the car after it's been off the road for so long without destroying it within months.

 

The car isn't even running yet so I might be lucky to get 5bhp :rofl:

I would say run it at a fairly low boost setting (less than 10 psi) then get yourself to Thor for a few runs. You can then do quite a few runs, measure the A/F ratio, and slowly raise the boost.

You then stop raising the boost when A/F curve isn't coping, you run the risk of detting, or you're producing so much HP you're crapping yourself!!

Top post by Mr Jaffa!

 

To add to it Chris I would say 10 psi on true T28s is gona give you more power than 17psi on T25s;)

I've been thinking about this recently. Please correct me if I'm wrong but the advantage of bigger turbos is that they don't have to spin so hard to generate the same boost - the charge will be therefore be cooler and more efficient. Ultimately bigger turbos can generate more boost at a lower temperature, I s'pose effectively your putting more oxygen into the engine as the air's cooler and not expanded so much. The same boost will have a more pronounced effect on the power output.

 

Hmm...I think I've just corrected myself....I'll get my coat.

Chris you missed fanny magnet off your mods.

I've been thinking about this recently. Please correct me if I'm wrong but the advantage of bigger turbos is that they don't have to spin so hard to generate the same boost - the charge will be therefore be cooler and more efficient. Ultimately bigger turbos can generate more boost at a lower temperature, I s'pose effectively your putting more oxygen into the engine as the air's cooler and not expanded so much. The same boost will have a more pronounced effect on the power output.

 

Hmm...I think I've just corrected myself....I'll get my coat.

 

Almost - bigger turbos flow more air volume at lower boost - hence lower charge temps - so you can get more power from a big tub - say a t67 - running 12psi, than you would from a smaller tub like a t25 running big boost.

I would say run it at a fairly low boost setting (less than 10 psi) then get yourself to Thor for a few runs. You can then do quite a few runs, measure the A/F ratio, and slowly raise the boost.

You then stop raising the boost when A/F curve isn't coping, you run the risk of detting, or you're producing so much HP you're crapping yourself!!

 

the downside of this is that the rolling road will show that everything will be fine as you have 555's etc to 20+psi this does not mean that it will be reliable or safe due to your stock internals , not sure that your pistons would hold up to well at that sort of boost even if the A/F curve etc is spot on

 

Ryan

I've got all this to come.

 

Gonna have to get mine checked out.

 

So with my new T28s, how well will stock ICs cope.

If these are the same ones Vinz has on his then 15psi should be fine if everything else is OK.

Yes 15 psi is cool, it is the turbos you want to worry about more than the engine!

 

Plain 270degree thrust bearing T28's (can't take much more than 15-16psi), don't generate that much more power, so I think the internals will be fine as long as you get it mapped properly!

hasnt 51X got T28's - im sure hes running 20odd psi???

I think he has got the BB T28's?

20psi OMFG!

The differance from 9 to 15 was silly with stock turbos mine wheel spin real easy in 3rd in the wet and easy in the dry (granted my rear tyres are of a hard compond and I certainly plan to change when I get her back) but 20psi must be very scary.

I must say, this forum and chatting on it realy helps keep you motor-vated when the Z's off the road.

I can not wait to get her back!

 

But going back to PSI again, I have asked the garage to remove my boost jets after fitting the T28 jobbies so I can see what shes like (standard boost) with the T28s.

So going off the above, Normal is 9psi so what should I expect with the T28s still 9psi but more air movment is that whats being said?

So going off the above, Normal is 9psi so what should I expect with the T28s still 9psi but more air movment is that whats being said?

 

That seems to be my experience with TurboTechnics stage IIs and everything else stock. No more PSI but a lot more go!

 

Anyone know what the TurboTechnics "really" are? T28s?

 

But going back to PSI again, I have asked the garage to remove my boost jets after fitting the T28 jobbies so I can see what shes like (standard boost) with the T28s.

So going off the above, Normal is 9psi so what should I expect with the T28s still 9psi but more air movment is that whats being said?

 

it will depend on what the wastegate actuators are set at

Turbo Dinamics Roller bearing turbo, high flow 60 trim compressor wheel, CNC re-Profiled compressor housing, T25 left hand thread turbine wheel assembly, staggered gap / total seal turbine end piston ring fitted, 0.64 A/R turbine housing, up rated actuator.

 

Thats what me got, all be it sat on the floor of the garage at the mo. I will also be having Dump Turbo Headers, larger Braided oil feeds etc..

just fitted stage 2/3 hybrid t25/28 i got from smithy!

apparently t28 turbines in t25 housings! so should be bl--dy quick off the mark. running Greddy coolers etc but on standard injectors. i cant decide what psi to run either! we'll have to compile an table for future reference once were all dicided!!!

T25/28 hybrid usually means a larger T28 compressor mounted to a smaller T25 turbine. (hense "hybrid" of 2 turbos)

 

this gives larger air flow with a quicker spool up.

 

they may also modifiy the wheels in the housings also :)

I think he has got the BB T28's?

 

it this gonna make much difference?? surely the amount of max boost you can run is going to be limited by the compressor housing/wheel, not what bearing you have. :confused: ok its gonna help with spool up, but would it make that much difference to boost?

just fitted stage 2/3 hybrid t25/28 i got from smithy!

apparently t28 turbines in t25 housings! so should be bl--dy quick off the mark. running Greddy coolers etc but on standard injectors. i cant decide what psi to run either! we'll have to compile an table for future reference once were all dicided!!!

 

you need to change to 555 injectors - if you are running with standard injectors dont run much more boost than stock or you'll find you are running lean.

 

i would recommend setting your car with 555's at 1 bar but dont advance your cam timing too much. Since you have got to take your engine out to fit the turbos I would also reccomend fitting the divorced wastegate downpipes, smithy can supply these.

 

You should like the turbos - i was getting positive boost at 800rpm :shock:

the turbos really take off at about 3000 rpm

 

 

Regards,

 

alex

just fitted stage 2/3 hybrid t25/28 i got from smithy!

apparently t28 turbines in t25 housings! so should be bl--dy quick off the mark. running Greddy coolers etc but on standard injectors. i cant decide what psi to run either! we'll have to compile an table for future reference once were all dicided!!!

 

Did these come with a fitting kit or did they just bolt straight on with the stock pipes?

I'm sure I have true T28's and not the hybrids...

 

Thanks for the advice.

I think I'll get it running at about 15psi and take it to Thorr or somewhere so they can test it out as it's running and up the boost.

im already running divorse wastgate down pipes so looks like i need to go for 555 next! are they a straight fit or do injector seats etc have to be modified??