ECUTune Stage III twin screw supercharger sign up - Page 88

SVXRide · #**1306** 04-01-2008, 11:23 AM

Tony,
In theory, we should be able to. It would all have to go "up", as we don't have the luxury of the "V" well that the vette engine has. So, I'm not sure you could fit everything under the stock hood.
-Bill

Dessertrunner · #**1307** 04-01-2008, 01:18 PM

I have been looking for the intercoolers to get some sizes but I think they would have to be built specially. I do think we have room at the sides of the blower and maybe we could move the SC slightly. Its worth trying because if we could do it we ewould get a major improvment in the power from the SC kit.
Tony

sicksubie · #**1308** 04-01-2008, 08:49 PM

definitely could be a huge improvement if there was a way to fit it.....

Nemesis Destiny · #**1309** 04-01-2008, 11:37 PM

Turn the problem into opportunity. Don't make the goods fit the car, make the car fit the goods.

Start producing hi-perf hoods! Everyone* will want one, supercharged or not.

* Everyone likely to include 10% supercharger customers as well as up to 47% posers.

Dessertrunner · #**1310** 04-06-2008, 05:41 AM

Have anyone done the calc's to see how much power is being lost due to the lack of intercooler on the SC or is it that the amount to be gained is not enough to make it all worth it. Here is a artical on working out all the maths.
http://autospeed.com/cms/A_109789/article.html
Tony

svxistentialist · #**1311** 04-06-2008, 06:28 AM

Quote:

Originally Posted by Dessertrunner

Have anyone done the calc's to see how much power is being lost due to the lack of intercooler on the SC or is it that the amount to be gained is not enough to make it all worth it. Here is a artical on working out all the maths.
http://autospeed.com/cms/A_109789/article.html
Tony

Yes

Graham in England supercharged my car, and is currently building a new engine for lots of boost. Graham devised a spreadsheet that takes the supercharger parameters into account. It will soon be "live" on his website.

Inside my photo locker are scans of calculations on the EG33 - Whipple twin screw. It shows the very major difference between running with an intercooler and without.

Study these:

http://www.subaru-svx.net/photopost/showgallery.php?cat=562

Incidentally, we chose not to use an intercooler, but rather to use alcohol mix injection [I run very well on that, myself

] It is definitely possible to use a charge cooler, but the fabrication is major.

Joe

Dessertrunner · #**1312** 04-06-2008, 07:40 AM

Joe so what ECU have or are you going to use?

svxistentialist · #**1313** 04-06-2008, 09:15 AM

Tony, I currently use the OEM computer, and I expect I will not need to go stand-alone.

Mine currently is using 5-6 lbs, and my ultimate goal is not much more than 9 lbs, but I'll see how that goes. 9-10 lbs will be my max, I think.

Paul our tuner is able to tune the SVX computer. Most tuners can't do that, they all seem to have software for the 4 cyl Soobies, but go wide-eyed when you mention 6. Even wider eyed when you mention 6 plus two knock sensors, they usually don't have enough channels for all that info.

What I hope to do is have the OEM computer work with the bigger injectors and the Nissan MAF. The advantage this will have for me is retaining the complexity of the OEM fuel map. I value driveability over power. Using an upgraded version of the standard fuel map I hope to retain things like the cold running system, work with the EGR system, react to and adjust for the aircon and so on.

For Graham's engine this will not, can not work. It is not finally decided what stand-alone we will use. We did like the AEM system, we spoke to them at a recent show. When it is more settled and details decided I will let you know the shape of things.

Joe

Dessertrunner · #**1314** 04-06-2008, 03:49 PM

Joe as usual you have made me think,
Does you guy add a new board to the OEM ECU or does he have a way to change the maps in the existing board.
Have you done any Dyno work on the car?
Tony

svxistentialist · #**1315** 04-06-2008, 04:14 PM

Hi Tony

No is the answer, we have not done any dyno work yet. On my own car in fact I have only driven it a few miles on the road during last year's show. It is down at Graham's in Somerset. Work on mine has been sidelined to let progress start with the new engine build and fabrication.

In answer to your first question, Paul is able to write to the original board.

For certain when Graham's is built and installed, it will get road tuning first, then will be due a dyno visit. Early days yet in the build process, but I'll give you info as soon as it gets moving.

Joe

Dessertrunner · #**1316** 04-07-2008, 03:41 AM

Joe I like the work your guy did, finally had time to look closly at them.
The calc's always use 8 compression are you changing the pistons or raising the heads?
The cooling refers to "Cooling" not intercooling is that because you using "alcohol mix injection" and is 80% normal.

It is really interesting what numbers the spread sheet gets and the difference in Cylinder Temp

svxistentialist · #**1317** 04-07-2008, 04:15 AM

Quote:

Originally Posted by Dessertrunner

Joe I like the work your guy did, finally had time to look closly at them.
The calc's always use 8 compression are you changing the pistons or raising the heads?
The cooling refers to "Cooling" not intercooling is that because you using "alcohol mix injection" and is 80% normal.

It is really interesting what numbers the spread sheet gets and the difference in Cylinder Temp

Yeah, Tony, Graham is a handy engineer to have around. He is thorough.

Those print-outs are at 8 because that was the figure Graham used on his original engine build. He shaved the pistons for lower compression, and yes, there is enough meat on them to do that. New low compression forged pistons for the new build though.

The cooling chart is a percentage input. You have to correctly calculate what efficiency your prospective cooling system will add to the soup. This is somewhat a grey area until you know precisely how good your cooling system will be.

There is no "normal" as such, but 80% is used here because it would be typical for a well installed water/methanol injection system. It would need to be pumping the right amount, at the right time, through the correct atomising jets and into the optimal positions, but 80% is not unreasonable. It is technically feasible to achieve over 100% with a good system.

BTW, it says "Cooling" because it does not matter to the calculation if you use Front Mount Intercooler, Top Mount Intercooler, Air/Water Intercooler or Water/Alcohol Injection. It only matters that you correctly calculate the efficiency of the cooling system you have in place.

Joe

svxistentialist · #**1318** 04-07-2008, 04:25 AM

Quote:

Originally Posted by Dessertrunner

Joe I like the work your guy did, finally had time to look closly at them.

It is really interesting what numbers the spread sheet gets and the difference in Cylinder Temp

This is the telling point for me. The target figure is keeping in-cylinder temperatures below 1075.

Above this level promotes detonation, and this is a recipe for melted pistons, we don't want to go there.

What I found surprising was the fact that 10:1 compression only made a few degrees more heat than 8:1. Yet, detonation as such is much less likely at 8:1. I think this is because the word "detonation" is used to describe multiple phenomena.

It stands to reason keeping the cylinder temperatures down is important for durability and power efficiency, it can't be ignored.

Joe

Dessertrunner · #**1319** 04-07-2008, 05:03 AM

Joe looking further at the sheets 290 BHP no cooling 9 psi & 340 BHP cooling 9.4 psi, I am not sure that I understand why the psi has gone up by only .4 but the cooled charge temp is 456 only 6 degree above the uncooled at 9 psi. Doesn't seem to make sense I would have thought that the carge temp would have been lower.
The intercooler charged with 456 gets a cylinder temp of 985 as opposed to 1139 cylinder temp but a charge temp lower at 450 on the uncool sheet. How can it be that a cylinder temp is higher on a engine developing less power and being charged with a lower temp air.
Hope I explained myself not very good at it but you should get what I mean, I might be reading the sheet wrong so if I am accept my apolage.
Tony

svxistentialist · #**1320** 04-07-2008, 06:01 AM

Hi Tony

You are reading the sheet wrong, but no need to apologise, I see where the dilemma is.

The 456 you are quoting, that does not refer to temperature. That is a measure of Cubic Feet per Minute, how much air the blower has to shove in there. The amount of hp the engine produces is directly related to how much oxygen we can get it to ingest.

If you look at the "with cooling" 340 hp chart, 340 is the hp you want to extract.

With 80% cooling 456 CFM of this denser, cooled air is all that's required to produce this horsepower.

Directly beneath this figure you will see 530 CFM. This is the amount of heated [non-cooled air, the compressor heats it] air the compressor would have to force in there to get the same horsepower.

Because of gas density, it only requires slightly more pressure at 9.4 lbs to get this correct amount of cooler air into the engine and give us 340 hp as opposed to 290 hp uncooled.

Or looked at another way, cooling is a cheap way of getting more oxygen in there. Without the cooling, the blower has to work much harder to produce the same horsepower, pumping 530CFM where it would get away with only 456CFM of the cooled charge.
[Plus of course the extra temperature will give excessive heat in the cylinder, adding another problem]

I hope that's put clearly and you see what I am getting at.

Joe