Looking for opinions about Borg-warner S300sx-60 turbo

[bogdanclung]

Hello,

Now I use a precision 5858 turbo, 0.63 A/R, on AAN, stock pistons regrinded to 8.5 comp. ratio, FCP 144mm rods, ported head, stock aan intake, stainless exhaust, mechanical lifters, Ti retainers, FCP springs, 7A cams. I managed to make 470hp at 1.8bar, with some problems to fuel pump, air filter and exhaust pipe, but after that I replace that problems and I raise boost to 2.1bar, but the power came all after 5500 rpm and ends quickly.

This is why I open first time a topic about 7A cams and I finaly get a reply from Jonus racing, to replace the 5858 turbo because this have a small exhaust wheel and after that the cams.

So in my attempts to sell the turbo, I find an option to change this 5858 with a Borg-Wagner S300sx-60. This have 60/83.5mm compressor wheel and 76.2/67.5mm exhaust wheel, 0.88A/R, and it's comparable with GT35 turbo.

This turbine was recommended to me by a fairly experienced tuner, but still I am afraid that I will not have a good mid-range, because is to big.

So I decided to ask you, what do you know about this turbine, or in what combinations of camshafts has good mid-range results for a power of 550-600hp

Thank you.

[Thuppu]

That dynograph seems quite laggy for that power level. How is the 7A cams clocked?

Here is my 600+hp dyno result with 7A cams and a Holset HX40 Super, and without boost control, so midrange propably lacks some power. http://koti.mbnet.fi/pro-ht/Audi_URS...ms_2degree.jpg

[bogdanclung]

yes it is very lagy

the cams it is 1.2mm ex. and 0.8mm in at TDC

[Thuppu]

Ok, that is close to the timings I had before. Try to adjust them to factory spec, all timing markings to stock (can be difficult if you have a adjustable cam sprocket). I got quite good results when removed the cam overlap to zero(I didn't measure the stock timings, but I assume there is no overlap), and it still seems to make good power to redline. Fuel consumption got also better.

[Rocco]

Why not a gtx3076 0,82ar for your desired 550/600hp with less lag than a gt35?

[Thuppu]

Why not a gtx3076 0,82ar for your desired 550/600hp with less lag than a gt35?

Or a Holset HX40S, same spool, more power and more reliability, and all this for less money.

[Rocco]

Or a Holset HX40S, same spool, more power and more reliability, and all this for less money.

Same spool too?

Can be suited with TIAL V-band exhaust housing?

[Thuppu]

Same spool too?

Quite close I would say. Klick!

[bogdanclung]

about the cams, now I was decided to install aan cam on intake, but any way the engine it's under reconstruction until spring time.

Any way, Kai from KBR racing tell me to fit 7A cams to 1mm ex. and 2.5mm in., but I will try all options that I have with this cams.

about turbo this are my options now: 5858 that I have, or s300sx-8375.

I also think to fit a s200sx-7670, but it's more expensive

[bogdanclung]

About camshafts, maybe someone knows a good recipe for regrind them, so can I have a good mid range

[Rocco]

Quite close I would say. Klick!

Be careful because this car was not tuned for high boost...

The hard boost only comes in higher rpm before that it spools "slowly"

Just an example, with a old gt3076 0,82ar done by Dmitri , the spool and torque was much more " in the turbo limit" than this gtx3076...

Much more salvage before , now in this engine the boost is far more gay

Anyway, Mr DD will know how are capable both turbos

[Thuppu]

Be careful because this car was not tuned for high boost...

The hard boost only comes in higher rpm before that it spools "slowly"

Just an example, with a old gt3076 0,82ar done by Dmitri , the spool and torque was much more " in the turbo limit" than this gtx3076...

Ok, but remember, my map isn't ready either. No motronic boost controll at all, and maybe the mid range will be better with proper boost request..? Propably also a small gain in spool when ignition timings are optimised for E85. Of course you can't compare that to a gasoline map.

[bogdanclung]

I use DTA S80 ecu, with boost control and many options
I forgot to mention that I use water injection, 100ron fuel and most important I can use ALS, but not all the time, trying to save the turbo, ex....