1bar boost on Stock CA turbo....how safe

Pinkfluffybunnys · Post by **Pinkfluffybunnys** » Fri May 23, 2008 3:48 pm

The only way this turbo wheel will shatter is if something hard gets into it and pushes it into the intake, as for the compressor wheel shattering for no reason....not easely.

Sorry this is incorrect information, because you are pushing you turbo beyond its capability you will cause the shaft to “over-spin” to produce the required boost end of story the slightest stress fracture in the metal could cause the Impeller to explode also you could possibly twist the main shaft forcing the wheels into the housings.

Im going to do it this way, Install chip dyno, Check power

Secondly why don’t you just upgrade the stock turbo? Why chance a failure that could cost you your motor or your turbo? Your spending that kind of money anyway, I am sure you could source a T28 for the price of the chip and dyno then just run the stock management which will work until you have more money.

I would suggest that you add an aftermarket intercooler or a straight pipe from turbo to inlet with water/meth or an intercooler with water/meth to cool down the charge, your engine should be fine if the tuner sets it right, it must not detonate/ping.

If you add water/meth you should get more because of increased timing capabilities

To my understanding you’re now spending more money on the likes of a “boost cooler kit” or what ever to just save you from the first place where you wanted to save money by not buying a correctly sized turbo.
Also running a “larger” correctly sized turbo will drop you intake air charge allowing your intercooler to be more efficient at a higher or stock boost setting. Do as Draco said “if your gonna mod, always remember to do it the right way, it will save you alot later”

gregT · Post by **gregT** » Fri May 23, 2008 4:28 pm

how will the injectors handle 1 bar boost. would the injectors be able to inject the right amount of fuel required for A/F ratio to be correct and run efficiently?

Draco · Post by **Draco** » Fri May 23, 2008 4:31 pm

You can go up to about 250 whp with stock injectors....maybe more

RBSX · Post by **RBSX** » Fri May 23, 2008 5:10 pm

Pink; thats some good stuff there as well

But T28s are flipin rare

But you right i should rather just go with a bigger turbo,
but the thing is im looking for cheap power

Does the RB20det have a T28..does anyone know

rat · Post by **rat** » Fri May 23, 2008 5:53 pm

gregT wrote:how will the injectors handle 1 bar boost. would the injectors be able to inject the right amount of fuel required for A/F ratio to be correct and run efficiently?

injectors are at 80% duty cycle at 0.8 as fas as i know

Riekert · Post by **Riekert** » Fri May 23, 2008 8:44 pm

RBSX wrote:Pink; thats some good stuff there as well

But T28s are flipin rare

But you right i should rather just go with a bigger turbo,
but the thing is im looking for cheap power

Does the RB20det have a T28..does anyone know

Not to rare.... I maybe able to source you one... getting myself one in a month or so....

veecee · Post by **veecee** » Fri May 23, 2008 9:18 pm

rather get a turbo that can handle the work that you intend to make it do.

and they not so rare - look in the back of a speed and sound and you can get a new T28 from mr turbo for just over 3 grand!!!

Draco · Post by **Draco** » Mon May 26, 2008 8:44 am

The highest boost for a normal T28 jernal bearing turbo is also estimated at 0.9......

Draco · Post by **Draco** » Mon May 26, 2008 9:10 am

Sorry this is incorrect information, because you are pushing you turbo beyond its capability you will cause the shaft to “over-spin” to produce the required boost end of story the slightest stress fracture in the metal could cause the Impeller to explode also you could possibly twist the main shaft forcing the wheels into the housings

This happens to turbos with the non metal exuast wheel for faster spool up, this sort is rarely found in SA, our turbos are mostly fitted with aluminum and light metal exuast wheels...why...we are cheap...and as hopefully most people know....aluminum does not shatter so easily...it bends rather well if it has to but shattering...................

Ceramic wheels....thats another thing....

Ceramic turbines are a big help in this direction. Unfortunately, their relative fragility limits the maximum boost they can supply

So if you have ceramic wheels in your turbo, which I highly doubt, boosting to high will be bad.....something might shatter, even on normal boost if the shaft bends under load.

Pinkfluffybunnys · Post by **Pinkfluffybunnys** » Mon May 26, 2008 10:44 am

This happens to turbos with the non metal exuast wheel for faster spool up, this sort is rarely found in SA, our turbos are mostly fitted with aluminum and light metal exuast wheels...why...we are cheap...and as hopefully most people know....aluminum does not shatter so easily...it bends rather well if it has to but shattering...................
Ceramic wheels....thats another thing....

First off your only taking about the exhaust wheel where as the intake will be exposed to the same force’s when over-spin and this is just a hope and a prayer tactic as any metal will fail catastrophically when exposed to forces exceeding its intended range of operation like when over-spinning also wheels are not examined or X-rayed for stress fractures at every rebuild. Also almost every turbo will over spin if the intended boost is beyond its capabilities made worse by the fact that the CA18DET has a small exhaust housing

The highest boost for a normal T28 jernal bearing turbo is also estimated at 0.9......

Sorry I also need to correct this; it’s all dependent on wheel trim angles and inducer housing sizes also I don’t know where this is coming from based on the fact that as you said yourself you boosted a T25 to 1 bar Also the most IMPORTANT thing about a turbo is flow rate look at the flow maps to determine the operational range

Draco · Post by **Draco** » Mon May 26, 2008 11:30 am

First off your only taking about the exhaust wheel where as the intake will be exposed to the same force’s when over-spin and this is just a hope and a prayer tactic as any metal will fail catastrophically when exposed to forces exceeding its intended range of operation like when over-spinning also wheels are not examined or X-rayed for stress fractures at every rebuild. Also almost every turbo will over spin if the intended boost is beyond its capabilities made worse by the fact that the CA18DET has a small exhaust housing

Exactly....I am only talking about the exhaust wheel, all compressor wheels are made from aluminum, I have never heard of a copressor wheel shattering whithout something hard going through it and causing the shatter, I have seen many bent blades because off bearing falior and bent shafts.

Sorry I also need to correct this; it’s all dependent on wheel trim angles and inducer housing sizes also I don’t know where this is coming from based on the fact that as you said yourself you boosted a T25 to 1 bar Also the most IMPORTANT thing about a turbo is flow rate look at the flow maps to determine the operational range

MR Bunny......Obviously if you use bigger parts the revs will be less causing less stress, are we talking about standard turbos or modded ones..........will the angle slow down the normal wheel sizes rotation by so much that it does not over spin...I think not, if you want 1 bar from a T25 or T28( not a modded turbo)....where the internals are the same by the way....the housings are bigger as well as the compressor wheel, but the exhaust wheel is the same size.....(yes, I confermed this with my own eyes when I built my T25 onto T28 housings) it will still over spin the revelutions it is made for.

As I said, I'd say 0.8 is safe still, I boosted 1 bar....and more by the way, my turbo did not fail but I still don't reccomend it, I reccomended 0.8 as a relieble boost pressure.

Before you quote me let me do it....I like this game

On the stock turbo I would say 0.8 is the maximum you will be able to go reliebly

Looking forward too the next set of quotes

Draco · Post by **Draco** » Mon May 26, 2008 11:44 am

O.....and you quoted me

The highest boost for a normal T28 jernal bearing turbo is also estimated at 0.9......

and asked where I got this from....

I got this from a tuner when he dynad my car with the T28 and from the Turbo place that reconned my turbo because of shaft play due to me boosting 1.4 bar for a while before coming to my senses and guess what, my compressor wheel did not shatter.....

Just to stress....I do not recommend more that 0.8 on a STOCK T25 and not more than 0.9 on a STOCK T28, not because I or a few tuners or the net or turbo shops say so but because that is my opinion....just that....opinion.....get it.

OPINION

Pinkfluffybunnys · Post by **Pinkfluffybunnys** » Mon May 26, 2008 1:39 pm

My point is and I have gone "Way" off topic with this one (Sorry RBSX and the rest of the club), Is "NO" don’t push the stock turbo past 0,8 and even then your on the envelope of the flow chart just invest in a bigger more efficient turbo you will not regret it as the biggest limiting factor in most cases especially the CA18DET’s case is the turbo.

Sorry Draco, not all T28’s are the same and if you’re happy with the fact that the internals are the same and that the expeller/impeller is the same then fine, I am going to back away from this “e-tug Fight” becuase this is just pathetic

Sokar · Post by **Sokar** » Mon May 26, 2008 2:23 pm

I'm seeing a pattern here, it seems that as soon as an SX owner sells their SX and they become exSX owners, they start correcting current SX owners about their SX'es..... Waaay funny, isnt it

Just kidding Draco, you know what I mean

, I've been there!

Draco · Post by **Draco** » Mon May 26, 2008 2:26 pm

True.....not all T28's are the same, ballbearing and specialized turbos is not what I spoke about, other makes have also got other sizes and so forth, the standerd Garret T28 and T25 turbos that came out on the cars is what I referred to.

I would just like to make something clear, when I said the internals, I meant the size of the shaft and exhaust wheel with the middle part housing the jernals and "internals", with other words, I took a T28, stripped the exhaust housing and compressor housing and fitted the housings straight onto my T25's middel body, I had already upgraded the compressor wheel to a T28, the exhaust wheel and miidle housing was the same size.

You said it....it's pathetic. That is one thing I agree with you on.

Sorry to everybody that had to endure this.