I5 GT Turbos 2871 / 3071 / 3076 / 3082 / 3582

[Rusty]

hp is only a calculation based on torque. hp doesn't actually exist.

to make high hp you need torque up the rev range. not that easy to do....and its all at a sacrifice to low end.

hp=torque x rpm/5252

Worth noting that's power in bhp and torque in ftlbs for those not so familliar with these things. Doesn't work with kW, Nm or other units.

[Jamo]

Useful if you're peckish

Top banana

[GazzaG60]

your correct andy it is hp. should have said.

this is the reason that stating the rpm is so necessary.

ie we may have 2 strong cars doing 350lbs ft ones an s2 making 400hp the other a tdi doing 160hp. both make the same power but the rpm means its representred in a different way.

you could take 2 of the GT turbos listed both set to make the same torque but one will be making more hp than the other due to the point at which it makes that torque.

[Rusty]

This is the constant trade-off with any car tuning.

Both 2871 and 3071 will pull to the redline for the level of tune I want, the 2871 will produce less peak torque due to boost reduction to avoid surge but it will produce desired boost earlier and thus useable WOT torque earlier than the 3071. I'd be interested to see how the a/r ratio affected the 2871 as the 3071 doesn't quite bolt into the space on a stock car. Assuming the 2871 is smaller, does that mean that it bolts in with airbox in place and without spacers on the engine mount or modifications to the chassis leg?

I'd be interested to see a direct comparison 2871 to 3071 and for .63 and .82 A/R based on theory at least. IIRC, Paul's work with Diesel_des and the 2871 used 1.7bar initially and then 1.9bar to red line?

[GazzaG60]

im not sure on the gt's but my sc6152e is basically a gt40 cold side with a t350 (0.63 stg 5) hotside. non bb 360 deg bearing

would be interesting to know what the gt equivalent is. id expect something along the lines of a 3076r

[Rusty]

Well the 30 in GT3076 would indicate to me that it's a GT30 cold side but then that's just being logical

[GazzaG60]

i was told a 3071r or a 3076r would give similar results, slightly less hp potential but with faster spool.

what i wanted was faster spool and the same hp potential. the "miracle turbo" as my turbo man called it. i was hoping that a 35r or similar would offer it. i remember at the rolling road day Sal's gt spooling quiite agressively compared with my less agressive offering.

[Rusty]

The other option is the TD turbo that DJones is running.

[Jamo]

Well the 30 in GT3076 would indicate to me that it's a GT30 cold side but then that's just being logical

30 refers to the compressor ( not trim)
76 exhaust side

exhaust wheel size affects bhp more than the compressor which effects spool

the 3082 which is the old 30/40 has the GT30 compressor wheel and gt35r exhaust

Look at the bhp trend below ( Garrett values not real world ) http://www.turbobygarrett.com/turbob...ochargers.html

3582 = 650 <- at this point compressor needs changing to get maintain flow for exhaust.
3082 = 600
3076 = 525
3071 = 460
2871 = 460

[GazzaG60]

thanks jamo.

so the gt35 is a bb t350? which would put me around the 3582 size mark.

[GazzaG60]

i like my garret based precision. i may just upgrade it for a bb version thats out now. im told -500rpm on them so that would be down to around the 3k mark for decent boost

[repo]

I seriously doubt a plain bb upgrade will give that much earlier spoolup.

[4WheelDrifter]

30 refers to the compressor ( not trim)
76 exhaust side

exhaust wheel size affects bhp more than the compressor which effects spool

the 3082 which is the old 30/40 has the GT30 compressor wheel and gt35r exhaust

Look at the bhp trend below ( Garrett values not real world ) http://www.turbobygarrett.com/turbob...ochargers.html

3582 = 650 <- at this point compressor needs changing to get maintain flow for exhaust.
3082 = 600
3076 = 525
3071 = 460
2871 = 460

The 28/30/35/... part in the GT family refers to the size of the turbo based on turbine inducer size.
The 60/71/76/82/... refers to the compressor wheel exducer size.
The R indicates the turbo has a ball bearing.

So for example a GT3082R shares the same centre and turbine sections as say the GT3071R, but uses the same compressor wheel and housing as the GT3582R.

[bimmerboy]

edited as post above this pretty much said the same.

[Avanter]

Garrett turbo sheet