RolexNJ

While you are on a role, why dont you list "all" the pro and cons of both system, so they class can learn today while you cruise around in that Green Bus. And thank you for answering for Todd too, even though I think he is a big boy himself.

lart951

One of weird things that happen yesterday was when I increased my boost to 24-25psi and added fuel my 4-6k rpm a/f ratio range was okay but I loss about 30hp instead of gaining any power. I thought for a moment there that it could be back pressure, but Special Tools is clearly convinced that it's the DME retarding the timing, I tend to agree with him.

kasturbo

What would cause that? Bad DME or was the KLR detecting knock?

lart951

ST, said the chips (authotority) are not suitable for my application, therefore can handle higher boost levels.

Duke

Hehe..

Well the big pro of the stock system, and it's a big pro, is the fact that it's already there. It's installed and working fine. Cold start-up, light load fuelling+ignition and ignition retard is factory tuned and is working satisfactory.

What's changed in aftermarket chips is mainly WOT fuelling and WOT timing. That is in 2d, meaning it's a simple row with rpm vs say ignition value.

This works fine in a low boost application. But when you start exceeding 18 psi the ignition values required for maximum performance without knock or too high EGT differs a lot from low boost.

That leaves 2 different choices, 1 to tune for maximum boost to be on the safe side. That is fine, but you loose performance during spool up and possibly in the first gears (when not maximum boost is achieved) as well. So overall performance and response is sacrificed a bit.

Choice 2 is to fill up the tank with higher octane when running higher boost levels but that isn't a very sophisticated approach. And with a standalone you could have a seperate tune for the race fuel to fully take advantage of it.

That's the basic stuff. Then we have the possibilities to alter fuel and timing depending on EGT, knock signal, intake temp etc with a good stand alone!

The stock system with Motronic doesn't even have a intake temp sensor after the turbo so it has no way of altering fuel/ignition with high intake temps.
And higher boost levels change the air temp enormously.

Then there's the little features such as soft cut rev-limiting etc.

As I said, not for everyone but if you have the time and knowledge to do it yourself or the money to pay a professionel to do it it offers a lot more than the stock system.

RolexNJ

And there it is from the guy in a Green Bus and Green Car,

Cheers

toddk911

uhhhh, yea.

I thought we had you set to get new chips already Lart????? LOL

Get them Auth, out of there. Especially at the boost you are running.

Loosing power??? Maybe not timing being pulled out but just REALLY dumping in fuel to compensate so being super rich robs a lot of power.

I don't think that Auth chips, or any for that matter, are that aggressive in adding/pulling timing on the fly....Anyone???

xtaC

Sorry guys, I didn't mean to start some kind of war in the thread, or highjack it. The reason I asked about going for a stand alone like the Wolf 3D, is that I'm running one in my 951 at the moment.

It's a complete plug in unit, apart from one wire for the TPS on the turbo 944's. I went this way because in Australia they are quite inexpensive, and offer complete flexability in terms of tuning, as well as the ability to tune around future mods, like a bigger intercooler, more boost etc, on the dyno, in real time, without messing around with chips.

My 951 currently makes 200rwkw on 1 bar of boost, with bugger all mods, and the Wolf setup runs it perfectly sweet.

Anywho, thats just my 2c, I hope I didn't offend anyone

hosrom_951

Luis,
Very nice, bet the car is fun to drive.

About authority chips, they have retard timing in them, if you had an egt gauge, you will see that it gets quiet hot.

About hally, he successfully burned LR stage 1 & 2 MAF chips for someone on renn (they are the same meter). As for Russell, he could also handle LR maf and their turbo's (check his site at the chip selection), that is if you wish to keep the current MAF and go for a chip.

lart951

Hussam, what I have is a authotority stage II maf converted to LR digital maf , power perfect (pro-M)

http://www.lindseyracing.com/Merchan...SSPOWERPERFECT

pk951

My Swiss made 418rwhp at 18 or so psi with k27 chips not to bad, I can't find the dyno chart.

Larts set up is very close to what My Swiss had expect for turbo his was a full garrett and MGE head.

Trucho-951

Luis, congratulations on pumping up the boost and finding more hp. However, once you get the issues with your MAF setup all worked out, you might also want to start thinking about using stiffer valve springs. As you probably already know, at high boost and high rpm the intake valves could experience valve float. If I remember correctly, the factory valve springs with 130 pounds of seat pressure are only rated for 12 psig of boost. As you run higher boost (24 or 25 psig) the valve springs will have a harder job closing the intake valves and you may run into some nasty valve float. Just a suggestion, good job and keep on happy boosting…

toddk911

What happens during valve float? The head pressure is too much for the intake valve to close?

At what boost are you closing in on possible valve float?

toddk911

That had to have been a 2.8 or 3L ???

RolexNJ

I am 99.9% it was a 2.5L that he did it on. Next, about valve float. Yes, stiffer springs are a good investment with the higher PSI levels. I had the ones LR had developed for my old 3.0L.

Click here for data on the LR Race Valve Springs. Hope that helps.