4722 replies to this topic

[Nev]

See you installed the race uprights with a 40mm raised spindles. Are you running that low a ride height on the road??

 

Yep, it's not really a big problem, I can get over speed bumps fine. The only real issue is entering driveways etc that have a rake/entry onto the road.

 

I think the front chassis is 98 mm off the road (might be more like 100mm now that I have fresh tyres). Rear is about 115 mm I think (from memory).  

[Nev]

Recently the car has been letting the idle revs drop too low when coming off the pedal, and on a few occasions it has stalled in the last 3 months or so.   After having a look on the Adaptonic forums, others have come up with a recommendation for changing a couple of params, which I did and videoed, sporting this season's fashionable ski wear Nothing particularly exciting, but it gives a bit of insight into how nice it is to be able to change this sort of thing on your own without having to drive to a tuner and pay £200+   I can't really test the changes until the engine is hot, so my plan is to "make it hot" in the Black Mountains tomorrow morning and take the laptop with me in the car for further adjustments.

Edited by Nev, 23 January 2015 - 08:50 PM.

[siztenboots]

What bike is that?

[Nev]

What bike is that?

LOL, is that the sole comment to my video! It's my girlfriends bike, about a £700 Giant, she uses it in the warmer months to commute and do some races.

Edited by Nev, 24 January 2015 - 07:08 AM.

[GeorgeBC]

What parameters have you had to change Nev? Surely something has changed if the car is struggling to idle rather than changing something on the ecu?

[Nev]

I fiddled with loads of params in the end, I must have tested stopped and retested abut 6 times, but none of it seemed to fix the issue. The problem has been getting progressively worse with time, so might be air temp related (from summer to winter), or possibly a sender unit going out of tolerance slowly. The engine has never idled well ever, even with the old old Courtenay map. It is lumpy until about 1700 and then upto 2000 it can splutter, after that it is smooth. This is all due to the cam duration + overlap + lift unfortunately, so can't be remedied.

Edited by Nev, 27 January 2015 - 10:34 PM.

[siztenboots]

how much map base ignition advance do you have , and how much reserve ignition ( ie. with full electrical load )  when running ie. actual timing

 

is there a standalone map for start and afterstart timing, then the main map for when cylinder head temps are normal.

 

minimum would be around 8° for start , but for warm engine minimum load could be 30°+ for lower rpms

[CHILL Gone DUTCH]

Is it not fly by wire ? Won't it need choke

[CHILL Gone DUTCH]

Try to put a bag on air filter

[FLD]

how much map base ignition advance do you have , and how much reserve ignition ( ie. with full electrical load )  when running ie. actual timing

 

is there a standalone map for start and afterstart timing, then the main map for when cylinder head temps are normal.

 

minimum would be around 8° for start , but for warm engine minimum load could be 30°+ for lower rpms

[Duncan VXR]

Nev has the DBW setup Cold start parameters in place on ecu to stop stalling and run pants when cold etc DG

[Nev]

I've finally bitten the bullet and decided to try and go ahead with my brakes mini-project with the kind and knowledgeable help of JoshuaUXB. Josh has already done a conversion on his car using the smaller Porsche Boxter calipers so we will hopefully be replicating what he has done, but with bigger sized kit.

The plan (and it is just a plan at the moment) is to:

1. Install 2 sets of rear calipers from a Porsche 996 GT2/3.
2. Buy 350mm rotors.
3. Fabricating our own 12 point bells.
4. Fabricate our own bracketry.
5. Rear handbrake question TBD.
6. Change the master cylinder plunger ratio to compensate for the extra pistons, this should improve brake feel and reduce peddle travel.
7. Fit a brake bias valve (under the bonnet (for ease) rather than on the dash).

We are both of the opinion that the OEM rear brakes don't work hard enough, hence the decision to fit the same calipers all round. This will likely over bias the rears initially, which is why we will probably need to fit the bias valve. I will probably also use more aggressive pads at the front to help with the bias a bit too.

Hopefully if we succeed (it's a lot of work!), this lot will allow me to lock out at any speed and fully use Nippers extra grip. My hope is to improve current braking from -1.4g to around -2.0g (which is about what a Radical SR3 manages).

 

The pic here show what whoppers they are (with an old upright and hub in the background for reference).

Edited by Nev, 03 February 2015 - 06:16 PM.

[Exmantaa]

HAve to read up on your current brake set-up, but you know that you can "upgrade" the rear calipers with bigger size pistons for more breaking power?

Done so in the US on the Viper that uses the same rear brakes. Maybe a good option to engineer that in the UK...

Edited by Exmantaa, 03 February 2015 - 07:36 PM.

[Nev]

HAve to read up on your current brake set-up, but you know that you can "upgrade" the rear calipers with bigger size pistons for more breaking power?

Done so in the US on the Viper that uses the same rear brakes. Maybe a good option to engineer that in the UK...

 

I'm not sure quite what you mean, can you give more info (maybe a link?) please?

[Exmantaa]

Think I posted the link here sometime ago. Will see.

 

Basically the calipers are drilled out and a bigger size piston is fitted. Stocksize is 36mm I believe and that US firm did upgrades to 38mm or 40mm piston. Or I think the pistons were sleeved.

OEM fitment and function, just with more breaking power.

 

Just curious, why the porsche calipers as most upgrade with the AP 2-pots on the rear? What's up front?

[Nev]

Oh, I must have missed that previous posting of yours, I would still be interested in learning about it though.

 

The conversion we are planning however will give a lot more than a bit more piston size on the rears.

 

The leverage moments increase from 280mm to 350mm will be significant. Bias control is critical as well, the OEM rear calipers never ever get close to locking, its always the fronts by a long long margin.

 

Josh's says that when he did his conversion with the Boxter calipers that the braking was so immense that he had to reduce the pressure at the slave cylinders by modifying the master cylinder spindle, otherwise he was locking it out at almost any speed with just a dab of his right foot. I doubt a few mm increase on the rear OEM caliper would achieve this level of braking TBH, though it would help for sure.

 

My approach has always been, if I am going to do something, make it worthwhile/significant, so I am attempting to duplicate the best existing proven system I know of (and then move the margin forward a bit).

 

Edited by Nev, 03 February 2015 - 08:43 PM.

[darronwall]

pretty sure the rears from a gt3 are the fronts from a boxster s

[Nev]

pretty sure the rears from a gt3 are the fronts from a boxster s

 

Not quite, they look similar but are different (pistons sizes and radius of disc in particular). My part numbers are 996.352.425 and 996.352.426 which aren't fitted to Boxters at all.

Edited by Nev, 03 February 2015 - 08:55 PM.

[CocoPops]

What is the weight difference Nev between a set of 350mm discs and Porsche breaks vs the standard VX setup?

[Exmantaa]

Oh, I must have missed that previous posting of yours, I would still be interested in learning about it though.

 

The conversion we are planning however will give a lot more than a bit more piston size on the rears.

 

The leverage moments increase from 280mm to 350mm will be significant. Bias control is critical as well, the OEM rear calipers never ever get close to locking, its always the fronts by a long long margin.

 

Josh's says that when he did his conversion with the Boxter calipers that the braking was so immense that he had to reduce the pressure at the slave cylinders by modifying the master cylinder spindle, otherwise he was locking it out at almost any speed with just a dab of his right foot. I doubt a few mm increase on the rear OEM caliper would achieve this level of braking TBH, though it would help for sure.

 

My approach has always been, if I am going to do something, make it worthwhile/significant, so I am attempting to duplicate the best existing proven system I know of (and then move the margin forward a bit).

 

 

Ehhh, It's not always an improvement when you can lock up rears so easily and slam rearwards in a hedge, so clearly that is not a properly matched combo...

 

But to the OEM upgrade; 40mm pistons instead of the 36mm standard size will give you 23% more clamping force at the rear, which maybe is enough for most here...

Edited by Exmantaa, 04 February 2015 - 03:38 PM.