Vitesse MAF Up & Running

[edh]

Just started the car, held my breath...........


plugged in the KLR []


...and it fired up [][][][]


Vitesse Stealth MAF, Vitesse chip/board, 3 bar FPR & 72lb injectors - just need to do some tidying & I'll be ready to roll. Road test report to follow.

One question - can anyone recommend a good switched 12v line to tap into in the engine bay? - I'm currently in the diag port as a temporary measure

Thanks

Ed

 

[Diver944]

Nice one Ed - welcome to the Vitesse club. You are already one step ahead of me at this stage as I forgot to install the 3 bar FPR and couldn't work out why my idle was so lean [&:] Doh !

 

[sawood12]

Good stuff. Keep us updated!

By chip board do you mean piggy back? If so how easy is it to install? I've read all sorts of things about soldering things into your DME etc.

 

[edh]

It's just a small board that slots into the 28-pin socket - I didn't order the piggyback (over budget already)

I have to say John's pre & post sales support is excellent - it must be good if he can get someone like me through the job! []

2 slight problems
- The 3 bar FPR has a push fitting - Pirtek made me up a new fuel hose for a fiver
- The Stealth MAF is a very tight fit - I have about 2mm of clearance to the hard pipe above & the hose below - that's after some "persuading" of the hard pipe to flatten it a bit []

Finish it off over the weekend & then book some dyno time to check AFR's & experiment with boost. Everything I read suggests Vitesse AFR's are pretty good straight out of the box & they have to be better than the AMD chip I've been running

 

[Guest]

John's stuff is great out of the box, as soon as you can get the piggyback I would recommend it .The flexibility it allows is well worth the extra money

 

[edh]

First drive today - it's not a night & day change, as the car was running well before I started. It's always difficult to separate your expectations from the actual experience.

Idle is rock solid - better than before, and less fazed by the A/C switching in, boost is readily available from 3k ish. There's maybe a slightly faster response to the throttle, but you still know you're driving an old-school turbo. I've plumbed in a vac line for a boost gauge but haven't found a permanent location yet. I need to get a passenger on board to read it.

The car is still a little jerky in slow traffic, maybe a little better than before. Might need to nudge the TPS a fraction...

Tommo - is the piggyback worth having if the tuning out of the box is near enough?

After all that, I'm very happy that I managed to get the job done with my very limited mechanical aptitude / experience. Is it worth spending a grand on doing this? - yes, if only for the flexibilty it allows me. I just need to get it out on the track now - Cadwell in Dec is tempting.

 

[sawood12]

Have you noticed much improvement in turbo respons in the upper rev range? E.g. holding boost higher up the rev range? or better accellaration/response higher up due to the better flow through the MAF?

 

[Diver944]

ORIGINAL: sawood12

or better accellaration/response higher up due to the better flow through the MAF?

I would have thought you won't get that much more flow with the stealth MAF as it still uses the standard airbox and more importantly the snorkel which is a very narrow pipe and definately the major restriction. Yes you won't have to push open the flap in the AFM so you should get better throttle response and quicker turbo spool up but you won't get a huge amount of extra flow.

As an experiment it may be worth removing the snorkel and seeing if that has a night and day effect. You will still retain the air filter and on these cold days the engine bay temperature will not be restrictively high from having an intake there

 

[edh]

I think the standard wastegate is the limiting factor at higher revs - my boost enhancer opens at around 17-18psi, then the boost gradually tails off to 11 psi at 6k rpm. Once you're on boost, the car has always picked up very quickly.

AFAIK the hole at the bottom of the airbox is smaller than the snorkel opening. As I understand it, the airbox is quite capable of flowing all the air I need.

I think the main gains from the MAF are to provide better control of the fuelling - improved part-throttle response, quicker spool up (my AFR's were very rich with the AMD chips as the turbo spooled), maybe a slight power gain & improved fuel consumption. Add that to the ability to run different boost levels without a re-map / re-chip.

I might have anothe run out today without the 2 back seat drivers [].

 

[Guest]

ORIGINAL: edh



Tommo - is the piggyback worth having if the tuning out of the box is near enough?

In a word.......... yes! Its the flexibility that it offers. You can run 2 maps so therefore a trackday setting for higher octane fuel and an everyday map.
Its not an urgent but I would give iut consideration

 

[edh]

I see - not sure if I can go for that though

I can get through £100 of Super on a trackday without spending more on BP Ultimate or whatever !

let's see how things look at Weltmeister

 

[sawood12]

ORIGINAL: edh

I think the standard wastegate is the limiting factor at higher revs - my boost enhancer opens at around 17-18psi, then the boost gradually tails off to 11 psi at 6k rpm. Once you're on boost, the car has always picked up very quickly.

AFAIK the hole at the bottom of the airbox is smaller than the snorkel opening. As I understand it, the airbox is quite capable of flowing all the air I need.

I think the main gains from the MAF are to provide better control of the fuelling - improved part-throttle response, quicker spool up (my AFR's were very rich with the AMD chips as the turbo spooled), maybe a slight power gain & improved fuel consumption. Add that to the ability to run different boost levels without a re-map / re-chip.

I might have anothe run out today without the 2 back seat drivers [].

Your boost tail off at higher revs is due to your turbo (I think you've got a stock turbo havn't you?). The stock turbos cannot flow the volume of air required to maintian boost pressure at higher revs. Your stock wastegate will have no trouble opening once your BE cracks open. It's keeping the stock wastegate closed that is the hard part.

I think you are right about the benefits of MAF. Any improvements in power and performance are not necessarily due to the workings of the MAF, but more to do with removing restrictions in the intake. As you free up restrictions in your intake side then it means the turbo can breath easier and will spool up quicker and maintain flow to higher revs. The more restrictions you have in your intake then the harder your turbo has to work to achieve and maintain any given boost pressure. I would guess that the AFM is the worst restriction then the stock airbox then the throttle body.

Regarding the switchable fuel maps you could have one for 95 RON petrol and one for 99 as it is increasingly difficult to find Shell petrol stations for my cars weekly feed of V-Power around Derby these days so it would be handy to put in a tenners worth of the standard stuff to get you to the next Shell station. I don't think the stock ignition system can advance itself far enough to take advantage of the extra RON's over and above 98 or 99 RON. I think you have got a maximum of 6 degs advance or retard and i'm not sure if that is enough. You'd have to go to a fancy solid state electronic ignition system to take advantage of that BP Ultimate stuff.

 

[edh]

We'll see how much a 26/8 can maintain to 6k once I get a DPW fitted next year sometime []
But right now, the wastegate must be the limiting factor - once the boost enhancer is open, there's nothing to stop the wastegate opening up & the boost bleeding away back to factory max of ~11psi.

My hunch is that a hot wire MAF must be more accurate / responsive than a mechanical flap. As for intake restrictions - we have seen cars with AFM make big numbers, especially midrange torque (and they can spool up quickly). Early spool up / power should also be influenced by accurate fuelling as the boost starts to arrive (my AMD chips just dump a load of fuel in & AFR's go very rich)

At higher revs, & WOT the flap is fully open, so this shouldn't be a significant factor?

 

[sawood12]

It's only a significant factor in that the area of the AFM's rectangular hole is quite small compared to the area of the MAF so that is the ultimate restriction and not the flap so your MAF should be capable of flowing more air than the AFM. With your DPW and a decent boost controller you will be flying even more than you are now.

My experiance with my K26/6 is that it hits max boost of 15psi at 3500 rpm then immediately bleeds boost linearly down to about 10/11psi. A k26/6 should be able to hold boost over some portion of the rev range (maybe to 4krpm maybe more? - will be more with your K26/8) so it must be my MBC that is bleeding the boost. I've got an EBC on its way to me so it will be interesting to see just how long a K26/6 should be able to hold 15psi - though i'm still on std injectors so i'm a bit worried that they might not be able to deliver the fuel at high revs if I find I can hold boost (so i've also got a wide band to install as well!!). Larger injectors is next on the list!

By the way, don't bother buying an MBC when you get your DPW - you can have mine if you're not going straight to an EBC.

 

[944Turbo]

Might be worth shimming the standard wastegate while you save up for the DPW, it will provide some preload on the spring and stop it opening before it gets the signal from the boost enhancer,
Tony

 

[edh]

Good suggestion, but I think I'll probably wait for the DPW - I can't spend any more time on the car now. (Need to use some spare time on the house instead!)

Having driven it for longer, I'm very pleased. The car is better on part throttle, and picks up faster - much better for city driving. Must book cadwell & see how it goes there.