powerprimers

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Postby furpo » Sun Oct 03, 2004 4:10 am

it would not suprise me if the wrc cars produce max torque and max hp at the same rpm point. they are limited to 300 hp by the way of a restrictor so they produce near to 300 from about 3000rpm to 7000rpm. they do it by using lots of boost down low and tappering it of up high.

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Postby ChrisD » Mon Oct 25, 2004 3:30 am

RIalltrac wrote:
Chris Dittrick wrote:Theres a few things i really dont like about that primer


Care to share, I read that primer on a fairly regular basis. Kinda hoping one day some of it will stick. I'd like to know what you disagree with, for comparison reasons that is.


A little late, but what the hell...

I posted the following in response to something in the turbo performance forum, so I figure I'll just copy/paste it here...

-------------------------------

Don't get me wrong, it is an excellent write up and very useful indeed.

I guess I'll just go through and pick at the things I have a slightly different opinion of. :)

I'll start off with comments on the SAFC + FPR trick. It says that it should be used in the 230-275whp range. Although it is a great idea in theory, I dont think it is too effective in reality. I lurk a lot on the mr2 board, and have found that a lot of people that have tried this seem to find that they can not make their car run any richer at a certain point with the SAFC. Why? This is because of the AFM. Basically, the AFM is already signalling to the ECU to inject the max amt of fuel that it allows. Adding fuel with the SAFC will therefore do nothing. That leaves you with the FPR, which can be used to add fuel. This is fine and will allow you to sort of crudely tune, but it isn't exactly all that efficient since you can only play with the base setting. The other thing you are left with is to reduce the amount of fuel with the SAFC and increase the base pressure, however the primer explicity says not to do this.

So what do you do. Several people have used the SAFC and FPR to get good results on larger than stock injectors. What do they do? Use the SAFC to make small changes. Get your FP in the ball park for A/F, and then make small changes with the SAFC. This will result in small changes in your timing maps. Since you are having this done by a skilled tuner, they should be able to watch for detonation for you.

Some other people do this with 540cc/min injectors. One member is over 300whp, and basically does this however doesn't make any changes to the SAFC over 4000rpm. Theres a few problems with that too of course. Detonation is more likely to happen at lower RPMs with high load. So 3-4000rpm you might be getting a little dangerous.

What do I think you should do? Well... I wouldn't waste money on an SAFC, myself. Hell I'm at 250whp with no SAFC at all. Crude tuning yes, and overly rich. But a 13.6 1/4 mile time doesnt lie.

However, to go any further, this is my plan.

With the used parts market the way it is, you can find almost complete greddy Emanage systems for the same price as a SAFC. Seriously. The emanage is way more adjustable than the SAFC, plus you get TIMING control! Now you can control your bigger injectors, or your stock injectors just fine. I still recommend it be tuned by someone who is qualified *very important*. This person must be willing to tune so you have zero detonation. I am not a skilled tuner, so I have a J&S Safeguard who will act as my ears when I do this. Although this is expensive, it is a great addition to almost any car IMHO. It's great to have timing control on even your EMS system, however, being able to watch for detonation in real time ALL the time is really really really nice. If using the J&S, you need to have it calibrated before doing this tuning.

Okay, so this is what you need to do. You will still need the FPR and the Emanage now, instead of the SAFC. Dyno is highly recommended, or some way of hearing for knock. Just like any tuning session.

Since emanage will allow you to datalog injector duty cycle, you will want to aim for somewhere in the range of 80-85% max. That is generally accepted as safe by most in the industry. The stock ECU will put you much higher, which is why this can also be useful on the stock injectors.

However, since you are REDUCING the load input to the ECU, the ECU will advance timing. Dangerous unless you can retard it somehow. This is where the emanage comes in. You will now need to retard the timing according to these guidelines to start with, and then play with them accordingly as you hear detonation.

I recommend you retard timing further than how much the stock ECU advances it. Why? Because the stock ECU runs extremely rich, which allows it more timing advance. You will be tuning for a much leaner A/F than the stock ECU uses, although it will still be safe. Shoot for 11.5:1. (I wont get into the discussions on the capabilities of the stock fuel rail at this time...this post is getting long as it is! lol)

on a USDM ECU:

-Reduce load by 20% ---> timing is advanced by as much as 10 degrees at peak VE; therefore retard timing by 10-12 degrees

-Reduce load by 10% ---> timing advanced by 2-3 degrees; therefore retard timing by 3-5 degrees

Notes on the JDM ECU:

-under boost, JDM ECU sees 1-7 degrees more timing advance. Be extra careful here. Retard timing if detonation is present.

-in areas of high VE (low rpm + high boost) timing is advanced <4 degrees

-in areas past peak VE timing is advanced by <7 degrees

-JDM ECU dumps MORE fuel than USDM ECU, but further advanced timing burns it better, and doesnt show up as extra-rich on A/F

Instrumentation is very important as well. If you see very high EGT's you may be retarding the timing too much. Do not continue to boost if you see EGT's skyrocketing.

Always keep in mind that your fuel pressure may need to be changed in order for you to reach that 80-85% DC.

Now, I'm not just pulling these numbers out of thin air. I have used Aaron Bunch's findings from his work with his techtom software. He has played with an SAFC on a dyno and found these numbers out by monitoring the timing maps as changes were made to the SAFC. RickyB was actually the person who pointed out to me that extra timing would need to be pulled because of the change in A/F that we were tuning to.

Since the stock fuel system can be pushed to 275rwhp, you definitely don't need or want bigger injectors or pumps before then.


That's kind of misleading in my opinion. To achieve that much power on the stock injectors you need to be running very high injector duty cycles, which isn't all that safe. Although the stock pump can make that kind of power, I wouldn't say it is a bad idea to upgrade your 15+ year old stock fuel pump well before this point.

You do not need to get rid of the AFM, the TVIS, the EGR or upgrade your stock cams, or port your head, or get a larger throttle body, or an aftermarket intake manifold, or get forged pistons or anything like that until you go over 275rwhp (and way beyond that for some of these things). Don't waste your money on these.


I agree and disagree with this one. To put it one way, no you don't need these things to make 275whp. However, some of these things will allow you to run a lower boost level to produce the same amount of power, which of course, will be much safer from a standpoint of detonation. Cams and intake manifold are good examples. With people showing dyno plots of 250whp cars gaining 30, 40, or even 50 whp with an intake manifold, that would allow you to run much less boost than without. I know many people with cams at the 275whp level. Why do this? Maybe they are on a CT26 still, and didn't want to upgrade the turbo quite yet. One other little thing is that it has been shown beneficial to slightly alter the TVIS activation point. Not necessary, but not a bad mod at all. I think other things like water injection that help to suppress detonation, are not given a high enough importance in the primer.

I agree with the comment related to the AFM, EGR, porting of the head, throttle body, and pistons. No need to touch those.

Alright, after all that, I hope it made sense to some people. I think that the power primer is an excellent resource, however some of the things could be improved in it. I think there are a few better ways that one could make power and keep safe, and even extend the power limits of the stock ECU.

:)
Last edited by ChrisD on Tue Dec 07, 2004 3:44 pm, edited 1 time in total.
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Postby Maloy » Tue Oct 26, 2004 2:50 pm

Im sure the 300hp and 600 lb/ft probably had a lot to do with the misfiring system that those cars were equipped with.
http://www.rallycars.com/Cars/bangbang.html
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Postby ChrisD » Tue Oct 26, 2004 3:10 pm

Actually, according to TTE, the power output for GT4's are as follows:

ST165

295 PS = 291 hp
380Nm = 280 ft-lbs

ST185

299 PS = 295 hp
459Nm = 339 ft-lbs

ST205

300PS = 296 hp
500 Nm = 369 ft-lbs

http://www.tte.de/st165.html
http://www.tte.de/st185.html
http://www.tte.de/st205.html
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1994 ST205 WRC
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Postby Trance4c » Wed Oct 27, 2004 7:22 pm

ya.. chris is right no a lot of those points.

Also, another thing to consider is the amount of money you would waste trying to do a lot of these mods when they're fairly crude. A lot of mods people do do not necessarily help in tuning, and even if you did want to tune with them its sometimes a hit or miss situation. I've never messed with larger injectors, more fuel or more boost, if you want to do all that go it the right way first, get the right injectors and a standalone. Good solid power, costs.

Something else that was never address in these topics is the effects of the FCD on the PIM signal. We have had a huge discussion on it in the past over on celica.net where myself and Chris had a lot of input. unfortunately there is no real good answer when trying to put piggy backs on the stock ECU (one reason why I'm completely stock these days).

Chris makes so really good points though, specifically with the SAFC. I have been able to make good gains with an SAFC and larger injectors on some honda setups but when it comes to dyno tuning and Toyota's.. its not all that great. Especially when we start talking injector duty cycles... wowa!

Also, the fact that if we do anything no matter what it is we still have this AFM in the system is critical. I don't care what kind of mods you've done, what kind of exhaust, etc.. if you still have this AFM in the loop you might as well be shooting yourself in the foot. Even with a stock CT26 and basically stock setup (ie stock engine, 440's, etc), just throwing a stand alone on it to trash the AFM is a huge advantage! All the people that spend gobs of money on FPR's, injectors, etc to get 275-300hp could have spent just a bit more and gotten the correct electronic management needed with a standalone and would have done themselves unbelievable favors in the future for anything else they would want to do.

Not enough can be said about how restrictive, good stuff chris! (as usual)
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Postby ChrisD » Wed Oct 27, 2004 8:22 pm

Thanks Clayton. :)

Yeah the PIM debate...still a hit and miss thing...I could probably unplug mine and watch the J&S to see if I get more knock/detonation...but thats kind of relative...I will probably be getting a wideband next spring and I could test then for A/F...my car is parked for now, some snow fell so I haven't driven it in 2 weeks.

Of course standalone could be brought into the system at any point, and gives you an endless range of tuning possibilities, without having to counteract any timing effects or anything like that. I'm not sure the AFM is overly restrictive, but there is something to be gained there I'm sure. One big advantage IMHO is moving the intake air temp sensor into the intake manifold, so that the ECU knows the actual temp of the air going into the engine, whereas the stock ECU wouldn't. Best examples are intercooler upgrades or water injection...the stock ECU doesnt know this and still applies the same correction factors based on the air temp at the AFM, without knowing that the system has become more efficient.

So yeah, no doubt that a standalone will make tuning faaar easier (for someone experienced), but for the guy who cant get qualified tuning or wants to do the majority of the stuff himself, an emanage/j&s combo is quite effective, and also allows you to see detonation in real time. But you are right, an emanage/j&s will cost just as much as some standalones if you arent careful! And of course, messing with this stuff is pretty dangerous if you dont know what you are doing...but it is another option out there. :)
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Postby ChrisD » Mon Nov 22, 2004 8:25 pm

I found this quote on the mr2 board by RickyB which reiterates what I have said. He basically points out a lot of the things I specifically analyze above.

The power primer does suggest using an AFPR+SAFC to get you through the 230-275rwhp range and it will work although your strategy will have to change as you get to 250rwhp and you find that you cannot richen the fuel any more. One is the AFM signal, but the other is that the 440cc injectors reach their limit around there at lower fuel pressures. At that point you must turn the fuel pressure up a little bit more and you will find that the system will richen up to were it needs to be under full WOT again. As you do so, you get into the range where the S-AFC only needs to be applied on less than full throttle boost but that the limits of the fuel system by themselves are enough to give you a good AFR at 100% throttle. If you or your tuner then really know what you are doing you can continue to apply the same tricks to get you up on larger injectors and progress beyond the stock fuel injector limits. How high you can go just depends on how high you want to go and how good you or your tuner are at finding the proper balance, although after the AFM flap is completely open you start to lose your ability to keep a good AFR both at full WOT and part throttle boost. If you are really motivated, you can break through the barriers. You could even rig up two AFMs and two stock ECUs and fuel systems to effectively double the potential limit of the system (I think I'm going to regret mentioning this hack).

I find all this discussion about how you can balance fuel, timing and airflow issues near and above the limits of the stock fuel system with FPR and black boxes somewhat tedious. The potential gotchas there are many, and they all bite hard. Given the high inherent risks, the smartest and most capable tuners are going to go where the money is better and the power rewards easier to pick. Even if you navigate through the obstacles safely you will probably find somewhere between 300-400rwhp that you have invested enough money, time and expertise getting there to pretty much have been enough to buy and tune an EMS.
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Postby Fastrac » Thu Feb 03, 2005 1:35 pm

Gary wrote:Off topic too :wink:
Maximum power: 108,920 hp at 102 rpm
Maximum torque: 5,608,312 lb/ft at 102rpm
http://www.bath.ac.uk/~ccsshb/12cyl/


Wow, it must have taken alot of GT*R stickers.... :D
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Postby Gary » Fri Feb 04, 2005 3:48 am

Not really. But you can figure out from the spec of the 14 cylinder version :wink:
The cylinder bore is just under 38" and the stroke is just over 98".

Here is the new link.
http://www.gizmag.com/go/3263/
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