Webbo's & Mark_K's rolling road figures.....

Webbo and I have got virtually the same engine mods apart from me having a H&S 2.75"(or maybe 2.5") DP and I ported my manifold too last time I took it off. Webbo has a GTiR Turbo and I have an Autointegrale Hybrid, which Benny managed to find out is the same spec as the GTiR.

Hybrid turbo
Pro Alloy FMIC
Pro Alloy SIP
Apexi Filter
Gtec2
Greddy Profec b II
De-cat
Supersprint or Peco exhaust
Walbro
Fuel pump mods too

We both went on the same rolling road at the same time(within an hour) and the results are below with both of our results being added to the same graph for a comparison.

http://i84.photobucket.com/albums/k20/Webbo/random%20car/WebboMark_K.jpg

We've discussed things over PM's and come up with some comments, but we'll see what other peoples thoughts are about the comparison.

So, what do you reckon?!

Cheers,

Mark & Webbo

Well you're both running different boost pressures and you have a different downpipe, so the results will be different.

But it also shows that your engine is breathing better due to the larger bore downpipe and can make the same power with less boost

very interesting comparison

quite simply Mark's car will feel notably faster on the road, despite having about the same peak bhp and torque figures

At some revs, its producing 75bhp and nearly 100 ft-lb more than Webbo's

And to add insult to injury (for Webbo) its doing it with significantly less boost

I'm struggling to believe that ALL of the extra spool-up and the flatter torque curve is down to the modest flowing of the exhaust manifold, but its possible, I suppose.

the downpipe is probably what's helping you to hang onto the power for longer, but it will be having very little (if any) effect on spoolup

I'd say its 50% port-matching and 50% turbo differences

However, it might be worth checking compression - a very healthy compression ratio will help with spoolup

Your car must feel really nice to drive with such early spoolup and with such a flat torque line

Mark, your turbo is much better than Webbo´s. Is it really the same spec?

What EBC are you using?
What is max torque and hp for you?

Webbo's looks like its running lean off boost, or is that fuelling still OK?

Both using a Greddy Profec b II, updated the list now.

We both have max torque of 265lb/ft & max bhp of 280bhp.

On the road driving comparison, the cars are virtually identical, Webbo's is quicker than mine at higher rpm as my boost drops quite a lot.

I think that the better spool up on mine is more to do with my Greddy settings than anything else as I have my set gain(I think it is) set at the same as my actuator and Webbo's is at 1.15bar, which it's supposed to be(close as possible to max boost without spiking). This might be why I have better spool up, but worse high rpm boost.

Webbo's done a great job with creating the graphs and it shows for a good comparison I think.

It has made me wonder about the turbo's, but Benny(who has the same as me from Autointegrale) contacted keith and they are the same spec as the GTiR that Barbz does/did at Torque Italia. Looking at the boost though on mine, it looks to have more charactistics of a superspool, but as I say, I think that's more to do with the Greddy settings.

Webbo's does look lean at higher rpm, but I think mine would do the same if I was holding the boost, but mine drops off quite severely, so it's slightly richer.

It is really interesting to see the huge difference in the RR results, especially as there is really nothing in it on the road - tested over quite a few sessions now

Mine does feel quite laggy, but when driving hard it stays pretty much on boost so the problem is hidden. I can only guess the late spool is because I haven't ported the manifold. I will also test the wastegate to make sure it is sealing properly and not leaking early boost pressure. I have changed the Greddy to Mark's recommendation but to be honest it is hard to tell if it has made much difference without repeating another RR session.

Mark, I meant webbo's looks lean at low RPMs, not high.

I have a very similar spec to both of you. When mine was on a RR then the boost graph showed that I wasnt getting full boost until 4250rpm, and it wasnt even on the chart at 3000rpm. On the road (looking at my boost gauge) it's already at 1 bar by 3000rpm and full boost soon after.

I would say that for both of you, your boost and subsequently torque is coming in waaaaaaay too late. Maybe it's your boost controller settings?

Also, both of you seem to be running too lean, should you not be running mid 11s midrange?

I'll add my two cents for whats it worth

I agree with davidub as you runing a fair bit lean,
realisticaly in the 11's

As for your boost coming in very laaaaaaaaaaate that will be your EBC settings

On my previous setup, which is simlar i use to get 1.35 at 3100

Ben

11.8 midrange max.

Ross

I'm not sure about Webbo's, but I am pretty sure I get my full boost(according to my Greddy anyway) before 3000rpm, but it doesn't show up as that for RR graph which is a bit odd.

Also, both Webbo and I will be getting checked again in the not too distant future as we've got Gtec2 high fuel chips either in or to go in.

If we've both got the wiring mods and Walbro's, what else can we do to get a bit richer apart from the obvious re-map, which again, we will both be getting in early 2008.

Cheers,

Mark

OK, so it's the RR skewing your results.

IMHO, I don't think you need a Walbro or wiring mod for the power you're running ... I guess it's the chip you've got that has you runing lean

Mark - I changed the Greddy Start Gain to a lower value as you suggested. In 3rd (same as the RR session), I now definitely hit full boost before 3500rpm. I need to go on a longer drive though and swap the SG back and forwards to check that it is really making a difference because it didn't feel that different.

I'm surprised that the RR showed my max boost after 4000rpm, as I'm pretty sure that wasn't the case on the road even before I messed about with the SG.

If my car was hot on the rollers, would it back the ignition off to such an extent that it would delay the spoolup by 500 rpm? I noticed it was hot on the rollers (40-45 degrees), which is why Charlie attacked it with a water bottle

Was this at Surrey Rolling Road?

It certainly was.

Mark

Try comparing your results to the SRR day. The boost does come in a lot later on the rollers, so I wouldn't worry too much, as long as it's the same as everyone else.

maybe the pressure sensor they use is very slow to respond, mine was the same, didnt show full boost until 4250rpm on the graph, but on the road its at full boost just after 3000rpm

Just adjusted some Greddy settings. Now getting full boost ~1.3 bar at a shade over 3000rpm. That's better but it needs a gain of 22% which is higher than most people run I think, previously I had it on 16% and was on full boost nearer to 3500. No real overboost/spiking even at 22% though

Changing the Set Gain (I previously incorrectly called it Start Gain) from 0.4 to 1.2 made absolutely no difference!

The terms are crap, Set, Gain and Set Gain, FFS why cant it be simpler!

It would be very interesting to see if you could see noticeable differences in side-by-side performance if you started at, say 20 mph in 3rd gear and just did a roll on. That SHOULD highlight the difference in spool up between the setups.

It's identical performance when up and running, but interestingly enough I mentioned to Webbo earlier on a PM we should try it side by side from 1500rpm and see what the difference is.

I lose boost higher up the rpm, but I get better spool up, so it should even up later on up the mph unless I short shift a bit so to not allow my boost leak(or whatever it is) to be noticable whilst driving.

I think when we've done the 40-100(but foot down at 30) timings before it's been pretty close, but we've never done it side by side. I think timings were late 8's or so when we did it previously.

What gear are you measuring that in? It still seems very late for your turbo! I'm surprised changing set gain didn't make any difference.

It was in third. Full boost by just over 3000rpm doesnt seem that late to me?

Not really looking at the results here.

Pretty similar to me with Webbo's being similar to Phil's who also has the GTiR Turbo, mine is just about 500rpm earlier.

Cheers,

Mark

mine was the same, full boost just over 3000rpm, but my RR graph didnt show that.

I'm a little surprised, as that's more or less the same as my RSR ... would have though the GTiR would have shown peak boost before then?

I saw your RSR on the same thread I posted above, it certainly appears to be very quick spool up for a GT turbo!

Do you have headwork or ported manifold etc?!

Mark

The manifold is ported, H&S downpipe, 3" induction etc... but no headwork (not yet anyway!). Actually, on my graphs on that thread, I had a boost leak (and a few other things) which was delaying boost by a few hundred rpm :mad:. I've a funny feeling that Highwayman might have had a problem also with his results on that thread (think it might have been a stretched throttle cable or something). Anyway, your results look good, I'm just saying that you might be able to improve your spool up on your existing setup, if you want to! If it feels good on the road though, it mightn't be worth the bother.

Just out of interest what are your full greddy settings?

Mine is something like:

Gain 16%
Set Gain 0.65bar
Set 52%

I think Webbo's is similar, but he has Set Gain at 1.2bar.

He'll be along shortly to confirm though I expect.

Cheers,

Mark

Isn't a Set Gain of 0.65bar very very low? Surely thats not utilising the turbo ptential you have much at all?

Chris

My previous settings, for 1.3 bar were:
Gain 17%
Set Gain 1.20
Set 52%

This gave me full boost around 3500rpm.

Changing the Set Gain from 1.2 to 0.40 made no difference.

I have now changed to
Gain 22%
Set Gain (irrelevant, swapped between 0.4 and 1.2)
Set 52%

This gives me full boost around 3000rpm.

This is the thing I don't understand!!

The graph still look ok and mine has a broader torque range etc, so what is the Set Gain actually doing?! To me, it seems that the turbo starts working as soon as the boost hits the base level of the actuator where as with Webbo's, it doesn't start working until it reaches the 1.2bar that his is set to, which obviously takes longer to achieve. What are the adverse affects of having a low set gain if any?!

Cheers,

Mark

Mark - have a look at what I read, it might help?



What I dont get is how the Start Boost can be close to the Set boost, one is like 0.4-1.2 the other is 50% or whatever so how can they be close to eachother. Have I missed something

Mark I think you might have it upside down mate The turbo will start working immediately because the wastegate will be closed until the Greddy tells it to open, therefore I dont think "Start Boost / Set Gain" will affect spoolup.

Here's my (limited) understanding- the Start Boost / Set Gain is designed to overrule the actuator setting so if you have a 0.6bar actuator, you could put the Start Boost to 1.2 and it should keep the wastegate closed until that pressure, thereby allowing you to hold more boost later on. Maybe that's why yours, set at 0.65 or something, is tailing off later in the rev range?