4722 replies to this topic

[Nev]

While its good to see a continued path of development on the engine and the learning process that involves , its some of the other aspects that concerns me.

 

To be honest, the sort of unwise road speeds (licence losing) you need before any aero makes a difference and even then it would still be a long way from overcoming the big compromises in the setup to get a very low ride height to work , plus the daft idea that a very low ride height on UK roads is anyway.

 

I am just worried about where this is ultimately going to end up.

 

 

Running at 7cm or 8cm clearance on the road is very awkward/impracticle indeed for sure, however when I was testing I still remember how effective the splitter suddenly became when at that height (even at 70 MPH).

 

For every day road driving the car is currently set at around 110 cm (measuring under the chassis front), which unfortuntatley means the spliter does almost nothing as far as I can tell. However, I am intrigued to experiment with it at 8 CM clearance (even if impractacle in real terms and deffo leads to poor road manners) just to see what I can achieve. In practice to get over speed bumps etc the car has to run a lot higher than this though, unless new (expensive) hub/wishbone geometry is used :o/

Edited by Nev, 17 October 2013 - 07:34 AM.

[cnrandall]

The splitter will work at all ride heights, its the underfloor that's sensitive to ride heights although TBO I imagine yours isn't anywhere near optimised so its going to make less of a difference than you might think.  Even with tricky uprights etc I don't run my car *that* low because the suspension geometry is more important than the last 10mm of ride height and also helps look after the driveshafts.  When you drop the roll centres through the floor the car gets quite unstable quite quickly.

[CocoPops]

Here's an idea... get someone proven like Chris or Jimmy or Cliffie to drive your car on track Nev, they can appraise it's qualities compared to other cars.

[JG]

 

Well, I had hoped to get out at the National this year, but thought it prudent not to the end, due to the boost and vibration issue.

 

So it's compromised. What I said wasn't a dig, just a statement of fact, you youself acknowledge it.

 

I would either ram it up someone's arse or spin off!

 

 

 

Its not going to drive itself off the track! Only you can do that.

 

 

I still have some other things I want to address, namely wishbone/uprights/brakes, particularly at the front before I'd consider the car was "complete". Ideally I want to be able to drop the front down to around 7 CM off the deck, as this is where I found the splitter made a MASSIVE difference.

 

 

 

So the bits that matter for the road aren't right, but the bits that bear no relavance what so ever for the road are? You should hear yourself. Splitter and spoilers for the road? for what? glueing it to the road? at 40 mph? at 70 mph? My, those corners on the motorway are a bit tight. its amazing that people that drive normal cars on the road are still alive. It's absurd. It doesn't make any sense at all!

 

If you are driving on the road at 100+ where you need downforce then you are a hooligan and have no place on the road, nor any place here showing off about it.

 

That ride height is also completely daft. why? why do you need to compromise it so much when there is no gain?  You're almost certainly going backwards.

 

 

It is hard to exploit the car on the road for sure, but I still enjoy it immensely even if just chugging around at 40 MPH on country lanes. I get a lot of satisfaction simply from sitting in the car knowing how it all works

 

 

 

Ah, so that's more like it. Its a pub car, built for bragging rights. That makes more sense.

 

 

clearly the car could be used closer to it's max capabilities.

 

 

 

 

You said above it would probably spin off, so it's questionable what they might be.

 

I'm sorry if it always come accross as negative, but someone has to put a bit of reason in this thread. Seeing cars like Mike's on the road is fun, clearly a car built for a purpose within a set of (quite relaxed in Mike's case) rules. It is clearly compromised for the road because it is optimised for its purpose. I just can't get my mind around why anyone would want all the compromises without the oposing optimises for something else. You said yourself you don't really like to pay to go round in circles.

 

/livinginadifferntworld

 

 

[Nev]

Goodness you are a spiteful arse. You presume so much and make a lot of wrong interpretations and personal judgements on a car that you've never even sat in and a person you've barely know (yet presume to pigeon hole).

 

You are desperately bigoted, you need to understand that other people are entitled to mod their cars how they like, for reasons and outcomes that might be quite different to yourself.

Edited by Nev, 17 October 2013 - 09:02 PM.

[Nev]

The splitter will work at all ride heights, its the underfloor that's sensitive to ride heights although TBO I imagine yours isn't anywhere near optimised so its going to make less of a difference than you might think.  Even with tricky uprights etc I don't run my car *that* low because the suspension geometry is more important than the last 10mm of ride height and also helps look after the driveshafts.  When you drop the roll centres through the floor the car gets quite unstable quite quickly.

 

I am fully aware of the compromises thanks, however I am experimenting simply for my fascination/curiosity. When I experimented with the car ride heights some 18 months ago I can still remember how amazing the down-force effect was on the front. You may only think it small, but I found the effect pronounced and have never experienced that effect and thus it intrigues me.

Edited by Nev, 17 October 2013 - 09:04 PM.

[JG]

Goodness you are a spiteful arse. You presume so much and make a lot of wrong interpretations and personal judgements on a car that you've never even sat in and a person you've barely know (yet presume to pigeon hole).   You are desperately bigoted, you need to understand that other people are entitled to mod their cars how they like, for reasons and outcomes that might be quite different to yourself.

I wasn't making it personal. It was commenting solely on the car. I've seen it many times. We've spoken many times even though you always confuse me with someone else. Bigoted my view may be, but so far you've not managed to convince me even a tiny bit that you are anything other than completely deluded, and I'm a pretty convincable sort of a chap. Make a sensible argument and I'll often accept I'm wrong and come round to your way of thinking (I should know, I manage a whole bunch of engineers) Heathy cynicism is a good thing for this forum. Not everyone will agree with you and if you can't take the criticism, then don't post I'm likely to carry on disagreeing with everything you post in this thread, and if you can take the opposing view (a sensible argument In response would be nice instead of the arse calling, but I'm thick skinned, carry on as you please) then keep posting, some people clearly like what you're doing it's gone over 100 pages.

[mbes2]

Nev & JG are BOTH ends of the VX scale when it comes to VX ownership

 

I think your both mad 

 

 

[Chris P Duck]

Nev & JG are BOTH ends of the VX scale when it comes to VX ownership   I think your both mad     

Agreed, I also think you both have too much free time (which I'm jealous of! )

[Duncan VXR]

Nev will be there tomorrow and look forward to seeing the latest works think I have stole some time on the RR from you but yours is planned to be completed Saturday

 

DG

[Nev]

Chris has kindly rung me up with a progress update, it seems all is well with the mapping and the drive train is still intact.

 

However the hub sensor signal (that the traction control requires) is erratic at low speeds, so he has had to send off for some extra circuitry and build a signal circuit board to clean up the sinusoidal wave into a pulsed square wave. This might cause a small delay in picking Nipper up, but I understand completely, these awkward niggles can be very time consuming.

 

We have decided to make torque the prime governing factor on the map, setting it to approx. 430 ft/lb and straight line it, thus allowing power to climb in an arithmetic progression, which it should do as the turbo is not being pushed to its limit. Thus the power + torque delivery in the power band (4500 to 8000 RPM) should hopefully be "NA like".

 

Apparently peak torque on the old ECU + map was a whopping 500 ft/lb @4800 RPM when he RR'ed it, and I even remember Mark Watts from CS telling me they had retarded the ignition and fuelling to try and reduce it down.

 

I also realise that in Post #1986 I made an accidental omission as to why the torque/power has jumped up so high, in addition to what I wrote it may be the case that the 3.5" exhaust system has helped with breathing too, hard to know the influence of each step without having done a dyno pull after each mod. Sorry.

Edited by Nev, 24 October 2013 - 03:45 PM.

[siztenboots]

430ft/lb@8000 = 650bhp

[jameso]

Yes... That's a known issue on the TC/ABS sensors relationship. That's why cs_ built those filters. Good work as ever nev. Standalone will be a huge improvement

[Nev]

I am sure it won't make anywhere near that theoretical 650 BHP. Chris was saying how "unrestricted" boost was never going above 33 PSI due to how effectively the engine was swallowing all the air. This means the limiting factor is the compressor size (only 71mm remember), so the torque straight line will point downwards somewhat. We are also keeping boost down to a max of 1.7 Bar BTW, so power will be capped far lower than that hopefully.

Edited by Nev, 24 October 2013 - 03:53 PM.

[siztenboots]

with the motronic , you can run with full safety systems upto about 1.55bar , beyond that you have to deliberately cheat things in the ecu.

[Nev]

The 1.7 Bar limit is due to the CC housing flexing with each boost cycle and metal fatiguing over time. Alex at Pro-Alloy (Nipper's old owner ) recommended keeping below 2.0 Bar ideally, so we have arbitrarily set the limit at 1.7 for reliability reasons.

 

Edited by Nev, 24 October 2013 - 04:23 PM.

[oakmere]

Drove passed EFI the other day and nearly stopped to have a look at Nipper but didn't want to waste there time with more VX chat. I will be going there at some point for a dyno run and for them to check my fueling.

[Nev]

Drove passed EFI the other day and nearly stopped to have a look at Nipper but didn't want to waste there time with more VX chat. I will be going there at some point for a dyno run and for them to check my fueling.

 

Poor Chris is understandably a really busy bloke and deals with all the issues most people on here haven't even the slightest clue about. Every car is so different from the next, each esoteric with their own "weirdnesses" that cause hours of issues. Nipper is no exception to this rule and is making him work 12 hours days, sorry Chris

 

His latest update is that my MVR 44mm waste-gate isn't man enough for the job (boost creep to the layman). I did get a hint of this when I was experimenting with my MBC (manual boost controller) and noticed that my min boost was greater than the spring rate that CS put in once the revs started climbing. As a result even on minimum boost settings the power can't be reduced below 470 BHP (dunno what the torque is for fact, but calcs would imply a min of 330 ft/lb @ high RPM, hopefully a good deal lower for low RPM). This is a little disappointing for "wet weather driving" but my own fault for buying a weedy 44mm waste-gate, based on reading other people experiences on Google

 

Also, there are puffs of smoke coming from the exhaust on overrun, once again this is hopefully due to my laziness of not installing my turbo oil restrictor (and oil pressure sender) on the feed to the turbo. Something that I need to address as soon as I get the car back or the turbo spindle might carbonise up.

Edited by Nev, 25 October 2013 - 08:35 PM.

[Dally868]

Hi Nev, there is a no way 44mm waste gate would not be up to the job, look on your power vs torque miles a way. there is a problem with your flow on cylinder head or cams. Good luck !

[alanoo]

Don't agree, there's loads of stories on the web about very well built engines where a 44mm would not make their job correctly (although you're correct, it may be due to cams or head specifics)