2871R goes rather nicely...

[S2central.net]

I share your concern Repo... AFR & EGT checks are needed be assured of safety limits... As to surge - we could only provoke it by stupid driving with intense left foot braking and full load with the throttle.

It will be interesting for me to see if I find much need for WG changes to cater for different installs...

[Prophet_dlx]

How comes these both graphs/values are so different???

There is a difference of around 60 hp mainly due to 034 droping boost from 4300 rpm on;

Is fullboost delayed by the porting on the kalsket setup?

Sorry for the hijack Mr Nugent...

[repo]

a80vant: You really are picky.

53,1mm wheel means ~54mm inducer in the housing.

In Kalske's car we saw 1,6 bar at I think ~2600rpm. Not that much delays there.

We needed to limit the boost to 1,3ish bar I think, to avoid surge. Then we pushed 1.6bar from 4500 to 7000, and it gave 458hp / 520Nm. 500Nm was I think at 3800 rpm.

It was quite a while ago, I think year 2005, and I have done more than a few projects since those days. Sorry for not remembering that precisely.

[S2central.net]

Forgot to say... this install has 3" downpipe and I think its deCATTed also... That will reduce backpressure and the tendency for surge also.

[EspenW]

It launches to 60mph in a sniff over 4 seconds. Its damn fast...

Ahem... that is 0-60 with rollout, remember Still no doubt that it is fast, though
(it looks like 0.9s rollout, which seems way excessive, please check the g-tech menu)

[S2central.net]

Yeh I know... Its set for 12inches... Just never bothered to change it... Not entirely sure I understand the purpose of that parameter though - something to do with trying to align Gtech data with timing gear used at a proper dragstrip ?

[Jonas_R]

I'm hopeful of making this and a 3071 setup sufficiently generic, but the only way to know that things are healthy is with an AFR (WB-O2) gauge...

Will keep you posted

Paul did you get the Zeitronix unit? I have a gauge for if you should need one.

[EspenW]

Rollout is the distance that the tire rolls before it breaks the second timing light at the strip. 12" is the average value for the average sized wheel. Rollout of 12" typically subtracts 0.3-0.4s from the time compared to using no rollout.
Example: edmunds.com timed the GTR to 3.9s w/o rollout and 3.5s with rollout. American mags like C&D and Motor Trend use rollout, thus getting some ipressive times. Euro mags never use rollout, and the German ones load down the car with a couple of wurst eating fellas in addition to loading the car with half the legal load, thus getting 0-62 times that are way slow.

Info on rollout:
http://www.edmunds.com/insideline/do...ticleId=130988

There is rollout info on the menu above the graphs that you posted, it is hard to see exactly what it says, but it looks like 0.9s, and that seems excessive.

[Rusty]

power figures using the weight provided, a guessed Cd of .33, A of 2m^2 and the losses that work on my S2 (fly = 1.35atw @ 7000) give power way into the high 400s

.zip attached.

Not sure whether I've made a mistake in a field or whether the GTech data is a different output to the GPS...

109mph at 6000 in 3rd is wrong based on the limiter in the S2 being at 95ish on the GPS.

[Rusty]

By applying 2 gearing of 2nd = 66mph @ 7400rpm and 3rd = 95mph @ 7400rpm the results are A LOT better IMO Not only are they more realistic but they also match rather well. In general my calculations are under as there are the effects of rolling resistance and inertia to take into account in the lower gears, up to 10% over a 4th gear RR run.

Anyway, new .zip attached.

[S2central.net]

There is rollout info on the menu above the graphs that you posted, it is hard to see exactly what it says, but it looks like 0.9s, and that seems excessive.

OK - good info... But Gtech calculates a rollout time here - I only have 12inch config in the setup.

I suppose I should zero the rollout then from now on... I need to get some more baseline data on the S2 on stock chips for one thing... Will try to get good launch results and power runs as well - two different techniques there...

Paul

[EspenW]

OK - good info... But Gtech calculates a rollout time here - I only have 12inch config in the setup.

I suppose I should zero the rollout then from now on... I need to get some more baseline data on the S2 on stock chips for one thing... Will try to get good launch results and power runs as well - two different techniques there...

Paul

You can also see the rollout time from the graph. Seems that the clock is ticking for approx 0.9s before t=0. It pulls approx 0.5G at t=0

Use 12" of rollout for 1/4 and 1/8 mile
Use zero rollout for time to speed (0-60, 0-100, etc)

[Billman]

I think 2871 is with 54mm impeller. And yes, it can flow 460hp. As a matter of fact, that compressor can do +500hp, but the turbine cannot. Even 460 is too much for that turbine.

Yes but if it can do 460 hp then why noone can with the GT3071R exceed the 450 hp even if it has a bigger turbine impeller?

I think with a 54mm (non Map-Enhancement width) compressor impeller everything above 450 hp is not really possible!

[Rusty]

Rollout is designed to compensate for timing inaccuracies on the drag strip as your manual will tell you. Get a stock S2 on stock chips and we can adjust various parameters to get a baseline for power curve generation.

[Jamo]

Yes but if it can do 460 hp then why noone can with the GT3071R exceed the 450 hp even if it has a bigger turbine impeller?

I think with a 54mm (non Map-Enhancement width) compressor impeller everything above 450 hp is not really possible!

Because bigger isn't always better with turbo's