malcolmd

LA964RS - glad to hear that you're content. Sound like you have the right equipment to meet your intended need.

Can you clarify an issue for me though (being a bit green on these matters). I might have thought there are given limitations of output/boost inherent to the turbo's design and geometry at low engine rpm that relate also to exhaust gas flow. Although the fixed boost controller might be asking for high boost at these times, the turbo might just not be able to deliver. So I guess what you are trying to do is extract the max available boost, (up to the set boost limit), as early and as soon as possible in the rpm range, and then maintain that same boost up the range. The expectation being simply that you are on boost earlier than might be available with the Monotronic controlling boost??

One wonders therefore, why Gunter/Kevin, when designing the program/data tables for the Monotronic during their exhaustive dyno testing would not have simply programed in higher boost at lower RPM if indeed power/TQ were superior with such settings. Perhaps it is a balance of various opposing parameters deriving the perceived best compromise??

All too much for me to fathom.

LA964RS

Malcolm

Here's my spin, and I hope someone like Jean or Kevin chime in here as they know more the techno-speak that best describes what I am going to say...or they may say I'm an idiot..either way it may give you a better idea of my situation.

Using the EBC is not so much about how much boost at what RPM, its more how much load. As you may have noticed the turbos really load and deliver sustained pressure in higher gears. The car really pulls 3rd-4th-5th. The direct opposite of 1st gear, which is, for the most part, boost-less. The EBC just allows me to load the turbos a lot more for low gear application. In the hills you run a lot of 2nd gear...almost always....so with what I call a 1.2bar program, because in the hills doing 2nd gear sprints I don't see any more than 1.2 bar boost, it delivers very good performance and power. Do note however, that if I run the 1.2 program out on the highway and load the turbos up in the high gears say 4th & 5th, it will go up in to 1.3 territory. Now with the 1 bar program it really stays at 1 bar...sometimes a little higher. That's fine w/me as I use 1 bar setting on the open road/highway and 1 bar is enough to land me in jail any day of the week.

I know the EBC is a sacriledge for tuners as you are not using their programing as perscribed, but for me and how I use my car it works quite well. When I switched to the 1 bar springs from Kevin, I just couldn't get the car to work "great" in the hills and the highway, so I had to set it for one or the other and if I set it up for the hills it'd want to overboost on the highway....not ideal, so the EBC allowed me to get the best of both worlds. Don't get me wrong w/o the EBC it was still a potent package, but now its, in my opinion, even better. I may be missing out on some TQ or HP somewhere on the band, but I can't tell...and the EBC allows me to make adjustments for change in weather as well....with race gas and beefed up internals, I am confident w/the package, and like I said, it works for me.

Keep in mind, my car is not a daily, it is a pure weekend hot rod that gets a good workout a couple times a month. If it were a daily or more civilized, I may have kept it w/o the EBC and just driven it. Bottom line, the stage 1 is a great kit, I just started all this because I wonder if I'd benefit from a stage 2 or 3 considering how I use my car.

Basal Skull

Hi again.
Not quite sure I understand either. Why would you be able to get more boost using a EBC. An EBC does not increase load. If you are not getting the boost you want with the motronic, (but you can get it using EBC), doesn't that mean the motronic is limiting boost because of knock count/the ecu doesn't feel it is safe?
Increase in altitude would cause the turbos to work harder to obtain the desired air 'mass' and I think you should see higher boost with the motronic cf sea level (some people have also mentioned that they see less boost in cool weather = denser air, less boost needed to attain certain programed air 'mass). If you are not seeing higher boost in higher altitudes, it's probably being limited somehow/some reason.

I think if you can get extra boost using a EBC(vs motroinc control) in increased altitude in lower gears - it means 1) you don't need to 'load' the turbos anymore ... ie. the turbos are able to make the higher boost , but 2) when allowing the motronic to control the boost, it is limiting it (likely for a reason).

LA964RS

I don't know Doc...the EBC is just this cool little black box that does "stuff". Let me break it down to the simplest parts: I push one button and it hauls ***...I push another and it REALLY hauls ***. That's kind of the basics. I'm sure there a few people on this board who know exactly how an EBC works...I only know that it does.

Basal Skull

I understand the 'cool box' factor, and believe you when you say 'it REALLy hauls'. I like gadgets a lot myself...

porschefig

Well, I have no idea how your beautiful 911TTs control boost but I'm going to go out on a limb and guess that this is why you'll make less power at more boost.

All the EBC does is allow a higher boost pressure before opening the wastegates (basically at least).
Your engine and turbos could probably produce (I don't know an exact number).. 30 psi (~2.04 bar) in 1th gear on flat ground. (More boost is available in higher gears because more load is created. In a NA the engine would pull more vacuum.) Your ECU isn't tuned for that because that boost creates too much heat given the intercooler and efficiency limits of your turbos and power starts to fall off/ things start to break.

Your tuners have probably tested/decided that above their boost numbers heat and knock will begin to occur that should cause timing to be pulled (for the safety of your engine) and power will decrease.

malcolmd

Porschefig - thanks - I'm sure there is truth there.

The way I see this is that any setup or any program is going to have limits. Those limits can be reduced if one narrows that range of circumstances where the program has to be at its best. Thus the narrower one's intended application, the more focused the program can be permitting improvements in performance. Once "focused" however, that program or setup will deliver lesser preformance if the car is operated in an applicationfor which it is now not optimized.

Porsche, in developing a stock program will take into consideration their need for engine safety so as to avoid warranty issues. It will take into account the need for a wide range of fuel octane that might be used by their customers world wide, not to mention the extremes of environmental conditions that their cars will endure. Therefore the program is found by some (most on this forum) to be "underdone" opening scope for aftermarket tuners to focus the program, improving the performance but at the expense of performance on the fringes of the application spectrum. The more focused the program or setup the better the performance in that niche application, but the cost is the narrow zone and the likelihood of suboptimal performance once outside that specific application.

So we have Phelix, who has found that in a Vmax application under sustained WOT, the higher boost of the larger K16/26s result in timing retardation caused by heat soak resulting in a lower Vmax than achieved with the GT1s. Nevertheless, higher octane fuel (RON 102 -104) might have seen a different outcome??? I suspect that the K16/26s got the car to high speed more quickly, but faded at the end.

Then there is Rob with his beautiful 964TT, whose application is higher boost under low load in second gear. That need requires a different approach, but no doubt once optimized for one applcation, some compromize to another application is likely to exist.

So I guess, a tuner with a desire for a commercially successful product will be seeking to target market that is not too narrow. To ensure that, the program cannot be too focused. Almost by definition, that means compromise.

The trick for the user, is to understand your application and find the best compromise, knowing that in so choosing it will never be perfect. This is just like the schism between high speed cornering and straight line speed/drag. You just can't have them both.

This is just my $0.50.

Felix

Just to clarify - the higher top speed was obtained with standard K16s and a Porsche 430 ECU.

I'm not convinced higher octane fuel would make much of a difference. Even a Secan intercooler didn't help more than 1 or 2 mph.

I agree that the K16/26s produce better acceleration than K16s but I think it's the tuning (basically, boost that's higher than it needs to be, particularly above 5000 rpm, that puts too much heat back into the engine) that holds them back from beating the K16s in all scenarios.

Kevin

Phelix, the tuning is designed for 90% street applications.. And your timing is pulled on your crap fuel when sustained load at 170mph plus.. Timing is pulled due to detonation. Chicken or the egg >> Crap fuel or boost. The threshold for knock is increased.

eclou

under sustained load, the likelihood of detonation is increased. That is why a series of tricks can help - colder heat range plugs, reducing plug gap, increased octane fuel.

Felix

Kevin, can you quantify how much "area under the curve" would be lost if boost was kept to under 1.1 bar or thereabouts from its current peak of 1.35 to 1.4, thereby allowing the revised curve to be sustained under prolonged high loads?

LA964RS

My recollection is you can get good juice at a UK pump. +93 and that's a "real" octane rating. Curious if that's "crap", what is a good octane rating to shoot for. As I mix gas 1/2 to 3/4 100 and balance regular I don't know what that nets out, but I can say I don't believe I've experience any pulled timing due to knock. I'll also say, I don't flog it out there in 100 degree heat either...like Jean, he hammers it no matter how hot it gets.

Felix

99-100 octane (RON method) is readily available in the UK and the most of Western Europe - theis equates to 93-94 in the US.

Jean

With good cooling, the adequate oil, good programming, nothing will happen at 100F and 1 Bar of boost (I run 98 RON here, 93 US). 20 minute sprint races are usual under 110-120F track temperature here until last week end. Obviously your performance will suffer.

Phelix, you can check the numbers on this graph from your 60-130 data. I am showing your Boost, FWTQ and FWHP vs. Speed and RPM in 3rd-4th and 5th gears.

Basal Skull

Interesting, why do you see peak torque, (similar in all gears) but at .7-.8 bar at ~ 5000 rpms in 3rd but you need 1+ bar and ~5600 rpms in 4th and 5th? Is it due just to heat/timing being pulled - and some balance between boost/timing to try to get the best output? If you put in a ebc and allow it to completely control the boost (as opposed to using an ebc just to limit the upper limit of boost and allowing motronic to modulate the boost at lower pressures), I'd guess you'd have much more torque in lower gears (but maybe that's bad or maybe not? I guess that's what LA964RS is experiencing when using the ebc in lower gears?). (Ie in 3rd, looking at the boost graph, it looks like it is being limited by the ecu).