On-the-bog

has to be said i don't think you are really comparing apples with apple boosted.

SmurfyBhoy

Cheap chinese bearings & poor grades of metal, may look and measure up the same but when sipping at around 100,000 rpm at very high temps is where the weaknesses show.

Have you had it balanced to check ?


Rough casings = poorer flow

Cheap for a reason,

Like chinese tyres or brakepads

Sure it may "work", a better quality more expensive one will work "better"

scooby2.5maz

iTrader: (16)

How old are you ? 18

SmurfyBhoy

He makes a good point tho,

Guys posted a 1/4 time for a one off setup which sounds like it could spool anything, with a unique gearbox setup too.

not saying the cheap turbo doesn't perform,

Saying it could perform much better with a decent snail on it

But he may be happy below 400 with cheaper replacement parts,

Just that folk may read this and think great my chinese turbo will be on full boost below 3k on a normal wrx lol

JGlanzaV

iTrader: (3)

This pretty much disproved the point you were trying to make.

Spool is virtually irrelevant in drag racing. Youre never below 6000rpm so as long as you have full boost long before then its no big deal.

What you are talking about is transient response, how fast the turbo can regain full speed. And it cannot be measured by a dyno....

You are talkig from a road car point of view not from the point of view of times...

And I would not recommend a uk 6 speed for drag racing as the ratios are ****e. Jdm spec c box or nothing. 4-5th change drops you right out of the power band....

On-the-bog

what a stupid reply.

boosted

How much dearer is the SC42 new than my £125 20chi?
I've basically maxed out lots of components on the car with it so don't (or can't!) run more power than it currently makes. So this £125 turbo has totally forfilled my needs and expectations.
Traction needs looked at to reduce my times now...
great conversation today guys.

boosted

Transient response then, very important to me and my times for sure. Surely lag is the same when the turbo is lagging behind after a gear change? Lags lag innit

SmurfyBhoy

I call B/S till i see a log or graph,

Dont believe a ***** turbo will be making 1.6 bar by 2800 rpm, would love to be proved wrong and it's easily done

You built a high compression engine which is maxxed at 380 ?

Whats maxxed ?

Injectors ?
Topmount ?

SmurfyBhoy

Don't confuse lag and boost threshold

Ball bearing turbo can be less laggy but higher boost threshold

boosted

2800 in 4,5,6th no probs. A hundred or so rpm later in the lower gears maybe. Injectors, manifolds, clutch, std rods, amongst other things.
When the car is back on the road I'll video the live fuel map as it comes on boost. Had to pull lots of timing circa 3000 as it's a pink monster!

boosted

What are we calling boost threshold now? If my foot is down and she's not boosting that's lag

SmurfyBhoy

As do most folk,

Boost threshold is the rpm turbo is effective in,

Lag is how long it takes to get to full boost when flooring it within the boost threshold,

Splitting hairs tbh but it helped me get my head round how a ball bearing turbo often has less lag when i read it like that

boosted

I often refer to your lag as response time.

SmurfyBhoy

http://blog.nulon.com.au/2014/05/tur...ost-threshold/

Good article where i read it

Henrik

iTrader: (5)

I'm with boosted on this one, regarding the drag results at least.

Time over 1/4 mile might vary between different drivers etc, but generally it seems terminal velocity is very similar between poor / good runs for the same power. Ie terminal velocity seems a reasonable yardstick to compare with, at least when vehicle weights are similar (which of course they will be as we're comparing subaru to subaru).

A turbo is basically an air pump, and as long as the wheels/blades look similar (nowadays extremely easy to achieve with cnc machines), then a turbo from a Chinese manufacturer (which is probably a large proportion of oem turbos too, don't forget) should perform similar to a turbo manufactured in Japan/uk/wherever.

Bearings might be worse for a cheaper turbo, who knows, but again I'm pretty sure even skf manufacture stuff in China now. Ie it's not true just by virtue of origin that something manufactured in China is worse than somewhere else.

SmurfyBhoy

How else do they make it so cheap lol.

Reducing costs by reducing quality.

I was told if i bought one and sent it away to be properly balanced and bearings upgraded it would be ok.

It may "work".

But a proper turbo ie garret/precision/borg are on another level.

scooby2.5maz

iTrader: (16)

You might need to a bit more reading on Google kamak the company that make the kinugawa parts they also make garret stuff . Just because it says garret !!!!!!! Doesn't mean garret make it !!!


Some very negative comments to my posts from on the bog which I find unecessary. It wasn't my kinugawa out spools whatever you can find on scoobynet . It was to show that a cheap turbo can still be ok and make decent power . If I ran this turbo on avcs heads then you can be sure spool up would be better . However a dyno graph doesn't tell you the whole tale. On the road it feels Awsome .

boosted

Reducing costs by reducing labour costs surely?

On-the-bog

Lag will be less on the road. But that will be the same for all dyno graphs. So it's comparable.

On a 2.5 4700 max torque is laggy. Go look at some of the graphs on the sc turbo thread. There's plenty of graphs out spooling yours by a considerable margin as well as pulling higher figures. Which is the whole point of the thread.

Simply put they don't perform as well as the mainstream turbos. That's what we're getting at.

JGlanzaV

iTrader: (3)

The only thing that is comparable is times and ETS. Dyno graphs are not comparable in any way shape or form.

The only way a dyno run is comparable is on the same dyno, on the same day. Etc.

As I eluded to earlier, you are talking about road cars where as boosted is talking about out on drag. There is a vast difference of what is acceptable imo. But the times do not lie.... It may be a pig on the road but I would not doubt the figures...

Edit - WB Tubbs

scooby2.5maz

iTrader: (16)

Incorrect : read the very first post from page 1 then you can post again what the purpose of the thread was

It wasn't " what out spools your kinugawa " ?? Was it ? It was ? Are they any good . You can't compare an sc turbo on avcs heads can you ? Like I said " for £500 on a 2.5 with 2.o wrx heads , cams it does ok

jayallen

iTrader: (31)

It's been proven many times on here that the cheap Chinese turbos are sh*t and are no way comparable with a quality unit. Yes, some have seem a reasonable peak figure but the spool is always poor, then there's the longevity......There isn't any.

If people are happy with them then fair play, much in the same way that some people are happy to shop in Primark and others in House of Fraser.

boosted

I would say you're wrong? I get excellent spool, excellent power and I've never had a failure. All for £125.

On-the-bog

Eh? Your the one who keeps saying the spool is excellent when it simply isn't and then say it's not about spool.

Simply put your turbo is poor because it's cheap

boosted

Lol, 1.6 bar at 2800rpm is good for a 20g no? How is that not excellent?
I just spend over £2k on parts alone building a forged 2.5, if I thought it necessary to spend a grand on a turbo I would of done so. But it's just not required.
I would like to know what exact components of my turbo you think are holding it back? I've ran almost a whole second quicker over the 1/4 than someone with an sc42 in an sti with Avcs, making 397hp. It's working for me 😉

SmurfyBhoy

The vid of that launch and the reason the time was so slow is down to the launch not turbo haha.

Video is there for all to see stop twisting facts to suit yourself.

https://youtu.be/IvuyOKuoMbQ

My car is a 2.0.
Launch fixed now and in 3rd by time old setup was in 2nd when launched.

Launch was set below where turbo boosted. Clearly a poor time.

Perhaps it the 2k of parts in your forged block. Ot the cheap chinese snail you claim to be good haha.

boosted

Or my drivin skills innit 👍
Happy to show you the car next time I'm at crail.

JGlanzaV

iTrader: (3)

Times dont lie Fella, i dont know why you are giving the guy so much hassle. The car is clearly very capable and wether you would fit one of these turbos or not is irrelevant.

It makes the power and does the times, you cant really argue with that.

Your SC42 is over 20hp down on where it should be, his £150 turbo is punching way above its weight by that measure....

SmurfyBhoy

I wasnt arguing about times.

It was about the spool of the cheaper turbos.


My point was how its an unfair comparison no ??

His forged 2.5 high comp engine would prop do a decent time with no turbo. (Joke).