Turbo Preference for 4age

[Big T]

I'll vouch for Phil's work. Excellent quality and VERY clean welds. This is the one he made for me (i added the ceramic coating afterwards)



Eddie.

[Megz]

Big T, Dom was telling me about it. that looks awesome! Very clean..
Michael

[myne]

Is there any real art to manifolds?
I know a competant exhaust guy that would have no probs making one, but I wonder what possible tuning could be done to the manifold.

Since it's effectively a 4:1 extractor, could tuned length help spool-up and reduce backpressure?
Is arranging it to firing order helpful? Ie 1342 all in a ring
Could angling the pipes in a natural spiral help?
What about wastegate outlet location/angle?

I've seen lots of interesting manifold designs, and while all make good power, surely the usual rules of gas dynamics apply?

I guess what I envisage as being ideal is something like this (and I'll do my best to describe.

From the port the pipes flow upward, allowing it to get out of the chamber quickly.
All 4 pipes are equal length, they curl around and meet in a 1342 arrangement. On about 5* opposite to the direction of the turbine
The collection pipe narrows slightly like a funnel.
The collector then splits off at about 40* for the wastegate. and finally the slightly spiralling flow hits the turbines.

[NVD05X]

does anyone know if the exhaust inlet and dump flanges on a HKS GT2510 are the same or similar to the Garret t series flanges... like a t28???

[1JZ-Rolla]

There are two types, depending on whether the intended application is for a GTR (twin turbos) or CA18/SR20 etc.

So yes, flanges are available from Garrett, so long as you know which type you have.

[NVD05X]

today i went for a trek out to Condell Park to visit GCG turbochargers in the hope of a bit of advise when it comes to choosing a new turbo for my car.

I had every intention to buy either the Disco potato GT28RS or a newer GT25 turbo, for a little bit quicker spool and higher hp flow..

after about 2 senconds of talking to the NUMB NUTS that was behind the counter (took him 10 minutes to come out also) i was totally shocked at how USELESS he was...

i asked him what turbo he would recommend and i gave him the stats of my engine and asked him to match up a turbo that would bolt on and give me the upgrades i wanted... and he was like ... yea, a t28...

so i said, "for the 1200 dollars i would be paying, would it noticably flow more than my current turbo, and would the spool be noticably quicker?"

his responce???

"Nah not really" "maybe a little bit"

i was totally dumbfounded at how a business with such a good name for themselves can employ people like that and stay in business.


now for the question...

im asking for opinions from those who have upgraded from a non ball bearing turbo to a BB turbo..

is it worth it?
did it spool quicker and how much quicker?
could you lower the boost pressure and still make the same power because of the higher flow of the new turbo after a retune?

i mean, after all the s##t you read in magazines and hear about from people about how kickarse BB turbo's are... this guy has killed my enthuisiasm

[Joshstix]

Honestly the benefit in spool with using a newer generation turbo is pretty much all about the aero-dynamics of the wheels and housings rather than the ball bearing centre. Garret have testing showing improvement in transitive response for ball bearing cores, giving a faster ramp onto boost when hitting the throttle while the engine is already above the boost threshold revs but it doesn't really reduce the boost threshold.

I have to say my dealings with GCG have been far from satisfying as well.

On the other hand my dealings with the guys from Garrett have been great. I've discussed general turbo sizing issues with a couple of the guys and we even toured the factory which was awesome. Really I found they were only too happy to help, and they weren't just trying to make a sale because they tell you to buy from dealers as the dealers generally have better prices anyway.

The reliability and nice transient response of the ball bearing turbo's mean I would buy one if I were in the market for a new turbo. But if, as I do, I already had a turbo setup that makes good power I wouldn't replace the turbo with an equal size ball bearing unit.

[4agte]

i have had less than impressive and expensive dealings with gcg too

[oldcorollas]

could you lower the boost pressure and still make the same power because of the higher flow of the new turbo after a retune?

this seems a bit odd.

boost as measured in the manifold is the pressure of the air NOT getting into the cylinders.
if the engine consumes the same amount of air, but the turbo flows more, then there is more air not getting into the cylinders = more boost measured.

for a different turbo to make lower boost, but somehow get more air into the cylinders and make more power, doesn't make sense.

it may be that because the exhaust wheel (turbine) is much less restrictive, so there is less backpressure on the engine, meaning that although the boost pressure is lower, the pressure differential across the engine is higher, meaning more air gets through (or more accurately, more air gets out of the cylinders due to lower exhaust backpressure from turbine)

or were you referring to turbine flow, and not compressor flow??
in that case, a more efficient turbo, will have less backpressure in the exhaust for a given intake manifold pressure, and thus you could make same power with less boost.. yes

[NVD05X]

Joshstix... so in your opinion, if i want faster spool, i'd have to change something else, like exhaust housing size?

[NVD05X]

or were you referring to turbine flow, and not compressor flow??
in that case, a more efficient turbo, will have less backpressure in the exhaust for a given intake manifold pressure, and thus you could make same power with less boost.. yes

yeh thats what i meant. the ball bearing units need less effort to spin creating less back pressure

that must be the reason why everyone that upgrades their turbo to a newer one can run less boost and make the same power, if not more, because more air is getting in and out. im not interested in running more boost. i just want a more efficient engine!

[1JZ-Rolla]

Another happy customer from GCG

I agree that if its response & efficient boost charge (less heat for same flow) that you are looking for, then its the design of the housings & wheels that will make a bigger difference than simply having a BB core. If its durability you're after then the BB design is the go, being able to withstand greater shaft RPM & load for a longer time than its equivalent bush bearing cousin

Be conscious of the fact that you can definately go too big. If you don't have a great understanding of compressor maps & the flow characteristics of your engine, then at least work backwards from your horsepower target (at the engine) to select an appropriately sized turbocharger based on the manufacturer's rating.

My money would still be on the 320hp BB T28 (p/n 466541-0001) on a 4AG for good response & flow potential for 180rwkw. If you must go for a disco potato or GT2871, ensure that you get the 0.64 A/R exhaust housing to keep some response on the little 1.6

Cheers
Phil

[Megz]

Also while we're on the topic of 4age turbo. I got a dizzy at the moment and i was hoping to run after market coils. How do you create a Crank angle sensor if you've got the dizzy?? And also wat coils are good? I have heard that hyundai elantra or something are good. Also heard bosch are good but not sure?
ANy help is much appreciated,
Michael

[4agte]

you could probably get the coil packs and cas from a map sensored gze

[cri_ag]

Also while we're on the topic of 4age turbo. I got a dizzy at the moment and i was hoping to run after market coils. How do you create a Crank angle sensor if you've got the dizzy?? And also wat coils are good? I have heard that hyundai elantra or something are good. Also heard bosch are good but not sure?
ANy help is much appreciated,
Michael

i assume you running aftermarket management? most need two signals from the cas, one to tell the position of the motor (24tooth wheel) and and another to tell it when cylinder number 1 is coming up (home signal) im fairly sure it was 1JZ-Rolla that told me that bluetop dizzys have a 4 tooth and a 24 tooth wheels so if you chop 3 teeth off the 4 tooth wheel you have your home trigger (providing you chop the right 3 off) or redtop motors have a single tooth wheel and a 24 tooth wheel so you can use them straight out of the box.

so basicaly again assuming your running aftermarket management, get a redtop(100kw) dizzy take the cap and rotor off and make a nice flush cap, instead of having a big dizzy cap poking out in the way of you turbo ect. then wire it up to suit you management.