New car and a long list to start on!

[333pg333]

I don't understand how you can change the map on a dyno without a piggy back or standalone? Does someone have an EPROM and are able to burn a new chip?

 

[bazhart]

Thanks to all those who answered most of the questions for me.

Just to confirm the car is a std 250 bhp car having covered over 200 K rebuilt as described and running with a std turbo (not even rebuilt) std wastegate (although rebuilt), std boost etc.

Apart from the parts described it is bog standard - this being probably the most remarkable thing about the performance we achieved so simply.

Anyway a forthcoming article in Porsche and 911 world will reveal what an independent journalist thought of the car on a very cold, snowy and windswept day up here in Bolton this week.

The track test we did was to see what other independent people thought about it and here at Hartech - I don't think we have claimed anything much ourselves except to imform and convey information. I don't like talking up a project - preferring instead to let the product do the talking (as all my motorcycle engine race wins provided in the past and hopefully the next engine will in the future).

To answer one question - it would be a huge problem to fit a turbo to a 944 S engine - as none of the pipes in or out would fit from the turbo (something we will have to do anyway with our own next 16 valve 968 head) but then at 3 litre it could be worth doing - not for a 2.5 me thinks and special pistons would also be neccessary.

I don't actually know too much about re-mapping (not really my generation) but left it up to Wayne at Chip Wizards (who did a brilliant job - thanks again Wayne).

One of our employees (Rob) does run the Honda 1.6 road legal drag car @ around 450 bhp and 10 secs for the standing quarter and uses a stand alone system and when he starts talking about it all my eyes tend to gloss over a bit as I am not used to the various issues and terminology - I am going to leave that to Wayne and him on this next engine.

However I would actually like to know what is done - if anyone can enlighten me.

Do they change the timing, obviously they do change the fuel mixtures by altering the injector timing etc, can they alter the cycling valve release pressures etc - I don't know - because this being a very standard car specifically designed as a simple conversion - I wanted the least altered as possible just to see if it would achieve the performance I expected - wehich it actually well exceeded. I actauuly asked Wayne just to get it running at std manifold pressures reliably without straining it too much - as a punchy repsonsive engine was all we were after and not a race car - this time!

I will be finding out a lot for myself in this next year on our dyno rig and stand alone set up - after which I should be able to answer more questions - but right now - it is not my field of expertise - sorry.

It would be great though if someone would just explain what can be done to the standard ECU set up and where its limitations are - over to you!

Baz

 

[DivineE]

ORIGINAL: Backyard Racing

Hi Ben

The anitlag setup your referring too will vastly reduce turbo life, even on new modern turbos imo, also you would need some wacky DV spring to withstand/hold back the exhaust mani pressure your going to create with the extra temps/energy, which will prob over come the inlet pressure so may never open fully anyway. I think with gear changes so fast the amount of air your trying to induce from the dv to turbine housing will be minimum. If lag is an issue then you dont have the correct balance of tune for what ever your purpose the car is being used/built for.. If lag from a standing start is a possible issue then on most standalone management systems you can set this up pretty easy in the ecu by ign retard and uping injection duty at a such selected rpm. This will create huge backfire thus generating spool. Once the car moves from the line the ecu will deactive this and switch back to normal map 4-6mph depends on set up, off course you need a speed sensor for all this work, ABS ring will work fine tho with a basic 2pin pick up..

Vnt turbos are good (been used on alot on other petrol tuned road cars for the past 5-6years as an aftermarket unit) but the only off puting thing for me is the massive torque spike at low rpm, this can easily course det and huge cyclinder pressure and with poor mapping total fail.. If i ran a vnt id map the TPS with a boost controler (stop fast spool at part throttle) along with rpm.

The most cheapest/effective vs £££ way to reduce lag is Nitrous..

Rob.

Beat me too it with the DV valve/backflow issue. I thought about it just after I posted. I thought a design like this should prevent backflow into the intake and also hopefully reduce pressure allowing inlet air to escape into the flow of exhaust gas more easily?

Scott I think the explosion is what is desired with these systems but with the rapid expansion finding it easier to spin the turbo to escape than blow the exhaust apart. I wouldn't be risking it if it hadn't been done.

I know there are far less dramatic ways to reduce lag but I thought it might allow me to use a larger than normal turbo without making it undrivable when I fancy putting in a quick lap of winning a race. Anyway its not all about speed, I like a capable car for sure but I also like the drama and it's far more exciting to see a car with a huge turbo lunging and flame spitting than a probably more capable but totally drama free 997 turbo putting in good times.

I had hoped the reason its not popular would be because its hard to sell the idea of wasting fuel to the public. It is still used widely in competition so it can't be that ineffective. I do worry however about the number of people saying turbo lifespan is still an issue. I wouldn't be running it all the time but if it kills my turbo every 5,000miles that could get annoying/expensive. I might try it once and see what occurs, just want to ask around first because responses like that one about back pressure are very helpful. Thanks all.

 

[Peter Empson]

Simple solution to solve lag, add a supercharger! Well it worked pretty well for Lancia []

 

[DivineE]

ORIGINAL: Peter Empson

Simple solution to solve lag, add a supercharger! Well it worked pretty well for Lancia []

Since you've already done the hard bit I think if you should now add a turbo manifold, turbo and intake pipe to your car as a mad scientist experiment I for one would love to see that.

 

[Diver944]

ORIGINAL: 333pg333

I don't understand how you can change the map on a dyno without a piggy back or standalone?  Does someone have an EPROM and are able to burn a new chip? 

You hit the nail on the head.

Over here there are many tuners (like Wayne at ChipWizards) who do just that. On a rolling road they map the correct fueling for a given load /RPM/boost level and then write it to a new EPROM. They can do a limited amount of work to the ignition timing too but once a car starts to depart too far from the norm you get to the limits of what the AFM and DME can achieve and so you then need a piggyback or standalone.

The correct fueling for Wide Open Throttle is very easy to do. You simply bury the accelerator pedal from low revs and take it through to the redline whilst recording what the Air Fuel Ratio is at each point along the way. Then you simply alter the parameters to deliver more or less fuel as needed at each point. Then you do the same thing again and again until you have it perfect. As a rule of thumb, John from Vitesse recommends you want the AFR to be 12.5:1 up to 7psi of boost and then a bit richer at 11.5:1 above 7psi.

The part throttle fueling is a lot harder to perfect and takes more time holding the car at many different load and RPM levels and aiming for a more fuel efficient stoichiometric 14.5:1

 

[barks944]

DivineE, to get anti-lag you just retard ignition. This way the fuel air mixture makes it through the compression stroke un-burnt, it then gets pushed into the exhaust system when the exhaust valve opens and this is when you ignite the mixture. You don't need a separate intake or injector afaik.

 

[Mike_Pollock]

Injecting fuel into the exhaust mainfold, is a recognised tweek, certainly for racing and one that Porsche have used ove the years.
Mike

 

[DivineE]

Hmm if the injectors continued firing with no spark every time the throttle was closed that should help cylinder cooling too[:-] I like that idea very much but could it be done with the standard ecu and how could you switch it on/off from in the car? Switchable maps controlled from a button identical except for that feature maybe? Has anyone done it?

 

[sawood12]

ORIGINAL: A9XXC

Injecting fuel into the exhaust mainfold, is a recognised tweek, certainly for racing and one that Porsche have used ove the years.
Mike

Yes, but the components around it are designed accordingly. Just adding injectors to the stock exhaust manifold and start spraying fuel in there will end in tears.

Anyway, lag is due to a number of components and not just the speed it takes to spin up the turbo. The best and most efficient way of reducing lag is not to be so crude as to start spraying fuel everywhere - that is why no-one does it now, it is through clever turbo design and other engine design tweaks. The latest generation of turbo's, though expensive now but price will come down with time, are almost lag free. And now that cars are finally moving from the manual gearbox, alot of the problem can be solved via gearbox scheduling.

As to dealing with turbo-lag in 944 turbo's - use the gearstick more!!

 

[barks944]

ORIGINAL: sawood12

As to dealing with turbo-lag in 944 turbo's - use the gearstick more!!

K26/6 + Apexi + modded intercooler works good too.

 

[MarkK]

Promax Level 2 kit and just strip the car to bare bones and add some plastic panels works brilliantly[]

 

[DivineE]

ORIGINAL: sawood12

And now that cars are finally moving from the manual gearbox.

Doesn't all this technology just depress you when you drive something like a mk6 golf gti though? Tiny efficient turbo, flat torque curve. It's got so dull now in DSG form it's barely worth staying awake for! No wonder people are no longer inspired by cars.

 

[333pg333]

I have to say that this sort of thing in the Youtube link doesn't do it for me let alone the premature end it will bring to your turbo and exhaust , but it's all subjective of course.

Thing I have to keep thinking about is how on paper many of us talk about lag and what to do about it. Sure when comparing the old stock turbos from '80s tech lag was an issue that could be improved upon but I have to say that having been in cars that were much more linear in turbo response....they're kinda boring. I'm not saying we should go back to nothing until 4500rpm and then BAM! Even with my current Tial turbo which is a ball bearing GT3076 it is very early to spool and it's almost lag free, or by comparison to running a turbo designed for a modified 3L motor on my stock 2.5L. That was more 'kick' oriented but still not bad by yesteryear's standards. However my smaller bb turbo winds up much earlier and feels almost electric by comparison. It also 'feels' flatter up top and just a tiny bit boring. So I just think by trying to chase this perfect non existent lag we almost may as well just put in a V8 and be done with it.

Just my opinion of course. []

 

[DivineE]

Hmmm apparently cutting the ignition is extremely detrimental to the cars health and rally cars are now using a different system relating to the intake to reduce lag which causes no damage. Listening to the cars in clips it sounds like repeated short bursts of the DV valve so maybe they're jetting charged air back into the inlet close to the compressor side of the turbo, like the variable exhaust side on road turbos?

Anyway enough on anti-lag I've decided to divert my attention elsewhere and have a new idea to think through.

333pg333 Does this mean you have your temporary car running with the new turbo now then?[]

Also MarkK if you happen to read this which exhaust do you have on the 400hp car? Do you still have standard manifolds?

 

[MarkK]

Ben-Exhaust is a 4inch Fabspeed(please have a look at the video on the fabspeed website it's really funny) but the front section has had some changes made to it by the chaps at Promax.......,i will bring it to a meet and take you for a spin,i guarantee you will like it,its got loads of personality with chirrups,whooshes,pops,rumbles.[]
Looking forward to reading about your car as it progresses take some pics of the different stages?

 

[333pg333]

Ben, prior to my crash I had the VR s5 turbo swapped over for the GT3076. I used it for a short time and was able to get a reasonable impression. To qualify, this turbo isn't the same as the one you have your eye on. It's got a smaller hot and cold housing and a 7 blade compressor wheel. So in effect it's probably more like a larger GT3071 and this is confirmed by riding in my friends car who has a '71 twin scroll. They are really great turbos and would be perfect for most people especially on road cars. Also good on a tight twisty track. So I'm going to keep it on there for the first half of our season and then perhaps switch it to something a little larger for the bigger track later in the year. We'll see.

So in essence I'm not entirely sure what to tell you, but I think a GT3076 with a .82 housing would be great for a 2.5L car. If you're going up to a 3L then go for a GT3582 sized turbo.

There's so many things you can spend money on chasing targets. Very hard to point at your absolutes let alone 2nd and 3rd choices. If the 3L option is within reach I'd think about that. If you can get Baz or someone else to do a bit of headwork too and then cam / headers / exhaust....then you've only got throttle body and intercooler left....haha, good luck.

 

[DivineE]

ORIGINAL: MarkK

I will bring it to a meet and take you for a spin,i guarantee you will like it,its got loads of personality with chirrups,whooshes,pops,rumbles.[]

[] I might have to hold you to that one Mark I would love to feel what can be achieved with a 2.5 it was my original dream 6-7years ago and having recently got a fresh memory for a 3.0 car it would be an interesting comparison. Plus there's always room for a few chirrups,whooshes,pops,rumbles in my life Many thanks for the offer.

ORIGINAL: MarkK
Looking forward to reading about your car as it progresses take me some pics of the different stages?

I'm hoping to get some pics this coming week or the one after of the car stripped and welded before the new panels go on. I'll also get some of the shameful interior before its all ripped out but I'm not putting new stuff in until the car has been sprayed so the new interior stays nice and fresh

p.s. 333pg333 that is not a game I want to get into but I've no doubt that I will end up going too far eventually! Always do.

 

[DivineE]

Ha ha I just watched those Fabspeed video's well I'm sold. That looks like a really really nice system, not entirely sure their car was driving right though. It seemed determined to push the front right like a Toyota Supra. 944's in my experience tend to stay straight at the front and just wiggle their tails behind them.

 

[MarkK]

Ben-Not sure what your goals are with this car but from your posts you strike me as someone that likes driving really hard more than polishing/originality?... the penny has finally dropped with me(thanks Peter E) that some of the most effective tuning is the simplest and the cheapest ie ripping strategic bits off the car to reduce weight, so what about this as a idea/suggestion..??
level 2 kit,or thereabouts to begin with plus any saucy extras if you have some budget going spare,intercooler,swishy exhaust system..
Exchange the front seats for lightweight quality and smart buckets(Cobra??Corbeau??),drivers on runners.. passenger bolted down.Original seats weigh as much as a house...
Rip out the rear seats,there is a lovely rear seat delete from Deutsche nine(one day i want one of these they look really tidy)- thats another ton of weight gone,still tidy looking...
Door cards... rip out for some tidy carbon or similar alternatives-they are lighter you can retain your power windows and central locking...
Ditch your stereo and speakers... of course if you want music ipods are light..
Exchange front wings for some quality grp replacements,these won't rot and are lighter plus front wing panels look great after painting(i was suprised by how good they come out)..better than i would have ever thought..
Exchange rear bumper for plastic item save some weight at the back(maybe this is a bit much for a road car)
The interior will sell on the spareparts section so you recoup some money back to contribute to all this..(i had people pestering me for mine)
GAZ or KW suspension will transform it no point trying to make a car go quicker with baggy suspension!
Refurb the lovely teledials silver or black maybe? get some awsome rubber (tyres!)
Uprated brake pads and fluids
Get the car running right in preparation for good thrashing,clutch,belts,service,fluids..
Rip out obselete alarm wires and mobile phone wires if there are some still in the car..these mount up over the years pointless weight(mine had loads)
You will save stacks of weight on the car,the car drives better,is less stressed,wears its brake components and pads/tyres out alot slower,its cheaper/simpler this way and the performance increase is very real with no experimental ideas that will probably break and leave you stranded in the middle of nowwhere with little or no mobile phone signal on a cold and windy day when the AA are really busy and you had somewhere important to go to...[],plus if done right it will have a real look to it???
Realise totally none of my biz but was just thinking out loud,hope thats ok,just some ideas..[](ilove a good project!)