Pace FMIC and running rich are your main problems I feel.

What are the possible causes of boost dropping so much at the top end? If my redline boost was 1 bar instead of 0.7 bar would that difference correct the fuelling ratio and give me a good BHP figure at 5500rpm?

I'm considering exchanging it for a totally standard coupe and never touching modifications again! I'm out of my depth to be honest

If you got 1 bar and changed the intercooler as Matty says, it would make a huge difference.

Ross

OK, thanks

how do I get 1 bar? what does "resetting up the boost" involve?

Well there is 2 problems as far as i can see.

1. The boost controller isnt setup correctly.
2. There is a boost leak somewhere causing problems getting to desired boost.

Resetting up the boost is putting all the settings back to 0 and running the car on base boost. See what happens. It could be a problem with the actuator?

Ross

I need to put it back on that same RR again for a longer session, editing boost gauge settings on the fly, and monitoring the effects it has on the fuelling, it's the only way I'm going to be able to understand what my car is doing, rather than asking any more stupid questions

Thanks for all the advice!

Matt



btw, I think the floor mat might have been jammed under the accellerator pedal ( ) when they did the test, preventing full travel. I remember it was pretty far up and I put it back in position before I left, but in my adsent mindedness didnt think anything of it at the time. That still wouldnt explain my overfuelling and poor boost holding though...

I think there was a small fly under my pedal preventing full travel on mine

If you're going back to Racing Line, they do a longer and more thorough test for £76.38 inc VAT or something like that, I was asking the guy about it.

I ran over 270bhp with a slightly inferior but very similar setup at two other rolling roads, your richness could be down to a mild boost leak, but would only account for 10-15 bhp or so loss I'd suspect, the rest is down to the rolling road reading low I'd suspect.

Where does the "500 rpm" out come from?

Joe

Actually Joe, Matt's low readings will be down to the fact he is only holding 0.7bar to redline...



Someone needs to post their graphs

i've got my graphs but can't upload to photobucket at work. I can email them to somebody if they would be kind enough to uplaoad them.

I'll PM you my email and post them up for you.

I'll post my graphs tonight. How much should the boost drop to at redline on a totally standard 20vt running 1 bar boost?

Your not standard though are you?

I'm not standard, but if a standard car drops to 0.7 bar as well, then I should be getting more than 215 bhp if everything else is in order...

If I had a boost leak then could that cause it to still hit the desired boost but drop off more steeply?

Will increasing the Gain on my boost controller help keep the boost at the top end or make it harder to keep boost? I've seen conflicting reports on this one using the search function.

There is something very wrong with these values - on that turbo you should see over a bar at 3,000 rpm.

You need to eliminate your boost controller as the source of the problem - if you have a mechanical valve then put that in and see if there's a difference. Failing that then join the two hoses up that go to the boost controller's solenoid and you should get base boost (do you have a 0.6 or 0.8 bar actuator?)

Once you're sure if the controller is the issue (or not) then you can think about where to go next.

LOL!, that's what I get by scan reading at 130am!!

Yes, as Matt used to get I used to see a lot better at redline, the Pace FMIC certainly caused a boost drop at higher revs, and caused peak power to be delivered earlier, less boost does mean less power, obviously.

I did run 290bhp with the unichip and a setup v.similar to Matts, running a bit more ignition advance, maybe not quite as much as his Gtec2, so I suspect we can say that Matts results are certainly not representative.

Matt, seeing as it was running a lot better before your boost leak, and now you get poor boost readings after the boost leak, checking very carefully for a leak is the way forward. Check the big thick fat pipe running to the inlet manifold, especially for cracks underneath there, mine had split once underneath. Check all your boost controller pipes, and all the hoses.

Even with the Pace FMIC you should see better boost levels earlier and higher up.

Joe

I have a 0.8 bar actuator. Is the boost controller's solenoid the silver box under the dash or the black one in the engine bay? I'll join the pipes up as I dont have a standard valve. Thanks

Joe, it didnt feel like it was running any better before the boost leak, here is what happened:

July: boost gauge shows 1.35 bar dropping to 1.2 bar at the redline. SBC settings are about 12 and 60 for gain and set

August: boost gauge pipe from dump valve splits causing comp surge and boost leak. After this is fixed boost gauge reads much lower (less than 1 bar) but car feels just as fast as it did before. I increase the boost controller gain and set to get the same boost gauge reading as I was getting before, the car feels MUCH quicker which makes me think that it was never really holding 1.2 bar at the redline, I cant see how that can have been possible.

September: It still feels as fast as it has always done.

If it's true that I should be getting 1 bar by 3000rpm even with the laggy Pace FMIC then something is definitely wrong. Could be the boost controller as above which I will attempt to diagnose tonight

OK, here are your first two runs Eldinho...

RUN 1

319bhp & 300lbs/ft

AFR & Boost

270whp


RUN 2

325bhp & 280lbs/ft

AFR & Boost

276whp


OK, some quick observations Your AFR is pretty rich on the first run, engine too cold perhaps? Your max boost is also only 1.3bar so it's not surprising you are down on power compared to Joe's 1.5bar runs. The 300lbs/ft torque is pretty good, it starts to drop off as you would expect towards redline as you run less boost. The torque curve actually follows Joe's previous PTS torque curve very well the only difference being less boost equals less peak torque. Your second run has better fueling and runs more boost but is down on torque however it doesn't drop off as quickly hence slightly more peak power.

You will notice how your fly power has exactly 49bhp added to the wheel power in all three of your runs. This is what I mean about the DynoDynamics rollers not using a coastdown method for fly power but simply adding on a fixed number. In reality your wheel power is the most accurate figure for these dynos and is the preferred choice in USA. Can I ask if all runs were done in 3rd or 4th gear as it has been hand written as a correction on two graphs with 3rd gear. The gear used will effect transmission losses and whp i.e. you get higher wheel power in higher gears. This is shown by you getting 6whp more in your 4th gear run compared to your 3rd gear. Based on this you can't really add the same fixed transmission losses as they have done but that is the way DynoDynamics do this. Most users like the whp figure as it is very repeatable and therefore accurate to monitor changes/modifcations.

All in all, good results and should be happy that all is well with the car

IIRC they used 4th gear on most of the coops but did run a couple in 3rd.

They ran mine in 3rd for some reason

mine was in 3rd as well.

Leighton

As you say on the 1st graph it shows that the boost peaks at 1.3bar. but when i checked what the blitz had peaked at it showed 1.46! This run was done in 3rd. I then asked if the next run could be run in 4th.

Also the engine wouldn't have been cold, it didn't actually have that much time to cool down as i was on the rollers quite shortly after i had arrived from an hour journey.

On the third graph the AFR is quite similar to the second run, fuelling around 11AFR.

After the first run I could have quite easily put the boost up, but didn't feel it was worth risking anything for what i thought was a misreading RR. And also i was expecting the boost to have peaked a bit higher in fourth. I forgot to reset the peak boost on the blitz after the first run, but it never peaked over the original 1.46.

But when peaking at 1.46 I would normally expect the boost to be highr than 1.2 at redline, it is usually around 1.25 on the road.

Mark

Just to add the third run was done in third gear, they did this without me knowing. I think most of the runs for everybody else were in 3rd.

Then again I could be wrong.

What does the boost actually read on your mechanical gauge as this will likely be more accurate than the Blitz for an absolute reading especially visually seeing what it spikes to? The heat won't be an issue on your first run especially if they have a good fan. It is only after a few runs that it starts to loose power from heat soak. That said, Joe does like to do the "max power" runs when the car is left on the rollers overnight so it is stone cold in the morning with cooler ambient temps... that does give you an extra 10-15bhp

The blitz seems pretty accurate when i have compared it to the boost gauge, although it is quite difficult sometimes as one is in bar and the other psi.

The other thing that concerns me is that on all 3 runs the line stops at different RPM!

I'll crank the boost up next time

That is normal, as soon as the operator starts to see bhp drop (or even stop climbing) he will stop the run. Obviously this could be at different rpm points based on the current variables.

Black one in the engine bay - join the hoses up and you should get 0.8 bar with that actuator, if the boost is lower than this you have a leak or dodgy actuator.

I'm pretty sure he hit the limiter each time!