Project Cobalt Candy - Discussion

Discussion thread if anyone has any queries or chat.

Regards, Simon.

I wouldn't get a piggyback ECU fitted. There will be a reason for the issue, otherwise you are just masking over the problem by going piggyback, plus piggyback ECU's are so 90's It might be worth speaking to FC Performance to see if they can advise as I believe they mapped the car

My Mapper has already spoken to FC about the car.

It would appear that the issue is probably the lack of mapping points on the original ECU. Because the rev limit was raised it has used up more of the mapping points and has not left enough to fully map the idle and cold start. Also the oversized AFM doesnt help!

Piggyback ECUs have improved hugely in recent years and are now probably more powerful than some of the top end standalone ECUs used in years past

Hopefully he will have everything done this week and I will report on the results.

Any chance of a clearer / closer shot of the dyno print out? I can't see rpm points or identify the lines on the graph.

I think his printer was low on black ink

The RPM numbers shown on the graph are 4500, 5000, 5500 & 6000. And the rumbers on the MAP and AF are 1000 RPM increments starting with 2000 on the far left.

The car will be going shortly to the Painter for the respray, but once it is finished I will be dropping it back to the garage to get the interior finished off, and I'll get them to do another power run (hopefully when the air temperature is a bit lower).

Does that mean we're looking at the following?

200bhp @4,000rpm
255bhp @4,500rpm
370bhp @5,000rpm
455bhp @5,500rpm
508bhp @6,000rpm
515bhp @6,500rpm

Putting a straight edge on the dyno printout I would say:

280bhp @ 4500
375bhp @ 5000
460bhp @ 5500
500bhp @ 6000
510bhp @ 6500

I will get a better printout when we do the final power run after the car has been resprayed.

Specialist paint bought today. Painter starting tomorrow

One of my biggest worries when selling my Coupe was that it would go to someone who didn't have the money or desire to carry on from where I'd left off. Seems I shouldn't have worried - it would appear it's in good hands and is recieving the attention it deserves (and needs....)

Couple of questions for Simon....

1) Given that a piggyback ECU will only "adapt" parameters of the OE ECU, what is the point of adding another ECU if the problem is not enough mapping points on the OE ECU? Surely the correct solution is to correct the mapping issues by 'fixing' the fuelling.

2) Did your dyno run stop at 6,500rpm for any reason? The engine is built for 7,500rpm (but I think we played safe and put the limiter at 7,300). Surely there's even more power to be had by allowing the engine to rev out more - the turbo is certainly capable of providing boost at those revs

Apologies for the oil cooler - I knew there was a very small oil seep from somewhere, but I thought it was the camcover gasket or the dipstick tube seal

Can't wait to see what it looks like in its new colour.

Hi Nigel,
I'm certainly not an expert in engine mapping so I cant really answer you question regarding how the piggyback solves the issues. All I know is my guys were confident that it would work, and they have been able to solve the cold start issues

The changes they have made to your original tune seems generally to be leaning out the fuelling a bit on boost. I remember you saying that your 502HP run had been close to the limit and that fuel had been added back in for safety. My guys have been able to lean it back out to maximise the top end. They are using a hub dyno for mapping which I believe is a huge advantage over a roller dyno (which I assume the car was tuned on for your mapping back in 2012?).

They still have some more adjustments to do. I think they still have to work on the low down torque as their mapping to date has mainly been the top end.

I think the rpm on the printout wasnt configured correctly as they did rev it above 6500. I will get a new graph done when they have the mapping 100% completed.

Im really looking forward to getting the car back from the painter to see how it turns out

Piggyback ECUs were always a 'sticking plaster' solution when the Coupe community first played with them and TBH, they weren't very successful - I spent a lot of money working with a well-known mapper trying to get a Unichip to work properly with the 20VT ECU, but it never ran right.

I'm also not an expert in mapping, so I'm reliant on what I'm told, and the experiences of others. FC Performance disabled some of the safeguards to get the 502bhp figure, which was great for boasting on the forum, but not a great idea for everyday use. Leighton (of FC Performance) always knew that my car was a daily driver and needed to be utterly reliable by making safe power, so we agreed to back it off to a figure that wouldn't be pushing the limits. Yes, it was a roller dyno, so the figures aren't as accurate as a hub dyno.

Regardless - if you've managed to get into the low 500s AND you've sorted some of the mapping issues without having to use an aftermarket ECU, then well done. That said, the cold start issue was never an issue in the summer months, but could occasionally be a pain in the depth of winter.

I'm really chuffed that you're taking the car to the next stage and I'm watching with a lot of interest (and a fair bit of regret from selling it....)

I really hope they do get the dyno calibrated properly when it goes back on with finished mapping as, at the moment, it doesn't bare any resemblence to a dyno print I've ever seen for a 2.0 litre 20vT (even if it is a 2.047cc :P), and I have collated ALL of the FC Performance dynos I can get my hands on, on one spreadsheet In fact it more or less mirrors DLT's non E85 results and that was a 2.5...

As said above, the rpm is off making any results dubious at best and the torque appears to bare no relationship what-so-ever to the power curve.

Get it all calibrated correctly (and the ink filled) and it should prove interesting to see

Yes they will do a proper dyno graph when the mapping is 100% finished.

The printout was really only to show the differences between the before and after.

It isn't so much that the hub dyno is more accurate (although it should give slightly higher HP figures due to there being no wheelspin power losses and no rotational mass of the wheels), it is the ability to hold the engine at any rpm or load.

So rather than doing multiple 3000 to 7500 rpm pulls, the mapper holds the engine rpm at each rpm/load point and can take his time adding and adjusting fuelling etc to assess the results at each point.

You're not skimping, are you?

As the song goes "if you're going to do it, do it right"

The colour looks amazing! Looking forward to seeing the finished car

i reaaly dont know how it is going to end up

Each photo looks different from the last, but I think it really depends on the light and the angle of the camera.

The base coat is a sparkling metallic silver and the pupleish blue candy has a tiny amount of sparklescent blue pearl in it, so it should look dark purple/blue in the shaded parts, then silvery blue on the flanks where the sun hits it

Looking good

I havent seen the new paint in person yet, but I suspect that the photos dont really do it justice.

The Painter sent me a couple of photos of the car sitting out in the morning sunshine and you can see the effect where the metallic silver bsecoat glimmers through the blue candy

Now that the respray is complete I need to decide on the wheel colour.

I'm undecided on whether to keep them them anthracite or go to a metallic silver (given that the paintwork changes from blue to silvery blue in the sunlight).

Any thoughts would be appreciated

I always thought that the anthracite colour worked well with the Moon Grey paintwork, but I agree it doesn’t work quite so well with the blue. I’d say a few shades lighter, but not pure silver.

I also think that 17” looks slightly too small now - amazing what a colour change can do to the overall proportions of a car.

Epic transformation, by the way. I’m so chuffed that ‘my’ car ended up with someone willing to spend the time and money to keep it going.

Maybe silver metallic slightly tinted with blue?

Each to their own, and all that, but I think any hint of colour on a wheel looks all wrong. I just can’t see it working. Do a Google search for “wheel colour on metallic blue cars” for some inspiration - I still think a “light anthracite” would be best - essentially a lighter shade of the existing wheels.

Forgive my two-penn'orth - don't over-egg the cake

Colour like sound tends to work better when it's contrasted; your complex blue will stand out better when it's set against something plainer. What Nigel suggests is connected to blue but more neutral.

Yes, I will probably run with metallic silver. Other colours go in and out of fashion, but I guess that silver is more timeless.

If you fancy selling the old turbo, providing it’s all good, drop me a little message

/

I'll ask the guys to check it out to see if it is still good. But judging by the photo they sent it may need a refurb.

You can have it free if you pay the P&P. Even if it needs a refurb it would probably still be cheaper than buying a new one.

Strangely there was no oil restrictor fitted to the old turbo

Sounds a plan to me. If you send me a direct message I’ll sort something out.

It has been many years, but I vaguely recall that there was a good reason for the lack of a restrictor. Haven’t the slightest idea what it was though - sorry….

Wasn't it due to there being a built in oil restrictor?

the new G series definitely comes with restrictors already installed, but I think they always needed to be added to DBB GT series turbos.

As an aside, should we not move these discussions to the Discussion thread

Nearly finished now

Turbo and new downpipe and oil lines fitted.

Full service including new timing belt, water pump, aux belt fitted.

New performance radiator fitted.

Just need to get on the dyno for a mapping tweek, then we will see how it compares with the old turbo

Be interesting to see the power delivery after the dyno session

Cheers Jamie

Sorry I posted on your build thread so can a MOD delete that?

Good numbers, is that dip clutch slippage....?

Yes that is what my guys thought. Maybe too much torque or maybe the clutch plate is due for renewal (after all I think Nigel gave it a good workout over the years!)

That’s a fast car

Yes Nigel wasn't shy when using all the power, lol

I have roughly drawn the new figures onto the old graph to show the difference in spool-up.

Hp generation seems to have improved by 500-700 rpm, but the torque generation is on a different planet

I picked up the car yesterday afternoon and got to test it for about 10 miles of country roads on rhe way home

The car now feels substantially quicker

It doesnt seem to reach boost threshold much quicker (maybe a couple of hundred rpm), but when it does come on it goes from zero to full boost in about 1500 rpm

So previously the power would build progressively as the revs rose, but now it has a massive wave of torque from 3500 rpm that propels the car to warp speed

Sounds awesome, enjoy

I did some road testing today to record the boost response in the real world.

The turbo starts to spool around 2200 rpm
2500 rpm = 0.18 bar
3000 rpm = 0.39 bar
3500 rpm = 0.90 bar
4000rpm = 1.72 bar

What gear Simon?

4th gear from about 30mph.

Impressive

I have plotted the dyno Hp and road test boost results onto the G25-550 compressor map.

The first x is 2500 rpm, the last 6000rpm.

As you can see it runs nicely in the efficiency islands until it is pretty much maxed out at 6000rpm.

I guess with that much torque available there is no real requirement to rev it out to the redline anyway

It will be interesting to hear how it drives - the GT3071 I put on it was still producing full boost at 7,500rpm, which was why it felt so frantic to drive (as well as a bit laggy...) This one looks to be all done well before the redline.

If the torque is as high as you think it might be, I reckon you'll end up needing a clutch, and you risk killing the gearbox, or if you're lucky, just a driveshaft.

Great to see the car is still being pushed to (and beyond) the limits

That's going to feel like a much bigger-engined car to drive - 100ft-lb stronger in the midrange.

Gonna need better tyres (and a lot more often!)

Won't you miss that ridiculous rush that it used to give between 6,500 - 7,500?

The compressor is pretty much maxed out at 6000 rpm because the maximum boost is acheived soo early (4000rpm). However there is no real requirement to rev the engine to redline now because it pulls so hard in the mid range

Joe is currently putting a G25-660 on his car, so he should get a lot more power at the top end where mine is running out of steam.

I'm happy with the choice I made as the purpose of the change was to get the best possible mid range response without loosing too much Hp - it is still making 480Hp which is only 8 less than it was when you had it

I think the clutch was slipping when the car was on the dyno (there is a dip in the torque in the middle of the graph). On the hub dyno there is no wheelspin so the full amount of torque would have gone through the clutch, however on the road there will likely be some wheelspin thereby reducing the load on the clutch and gearbox.

It probably needs a new clutch plate soon anyway as it has about 50k miles on it now. Any idea how much torque the Helix organic clutches are designed to hold on a Coupe?

The rediculous rush is now from 3000 - 6000

I seem to remember something like 330lb-ft. I was slightly over the limit, but you’re in a different postcode….

The clutch would occasionally slip if I left my foot resting on the pedal as it hit max boost, so it was clearly at the limit with the old turbo.

Have you thought about using the Blitz boost controller to limit the rate of boost gain? Going from no boost to full boost in 1500rpm will be entertaining for a while but could soon get tiresome. You have four different channels - they don’t have to use different boost rates - you could have different channels for different gain rates.

I specifically used channel 1 for when I had non-petrolhead passengers. 1.0 bar boost and a really gentle boost gain. It still made about 400bhp, but the gain was very gradual, so it was less frantic.

TBH I'm never really driving it with my foot flat to the floor like you were on your track days and runway top speed runs So the power should come on slightly more progressively when I'm feeding in the throttle on the twisty roads
I'll see how it goes, but if it does turn out to be too crazy I can turn down the boost a little .