Jump to content
Server maintenance Read more... ×
Trent250

Tuned extractors

Recommended Posts

Nice long primaries, are 6-2-1 so scavenging isn't going to be the best, merges look smooth but cant tell for sure from outside. Look well made from what I can see. All mandrel bends and they've tried to keep them all the same length. Might be tight fit in the bay.

Share this post


Link to post
Share on other sites

From what has been explained to me when they work depends on if they match the engines power range, this will determine if the are good for performance. Tuned length are made to enhance a specific rpm range of an engine, if your engine operates in the designed rpm range then its all good. 

Alot of careful work has gone in to that set by the look as the first bends in the primaries look to be around the same length from the flange, all mandrel bends. The primary to secondary collector looks nice with the secondaries pipe of cone, and the bends out the first collector are not to sharp. From what can be seen in the pic they do look like a nice set of extractors. Size and length of piping used is just as important as the design so if the pipe size matches your engine's performance level I can't see that these would be a bad think. What's the rest of the extractors look like?

Share this post


Link to post
Share on other sites

... 6-2-1 so scavenging isn't going to be the best...

Based on who's theory? It is the most studied and proven arrangement for a 6. 6-3-1 are more questionable in this regard even though HP has been made with them.

 

What size tube are they (diameter of primaries and secondaries)? That's the most important thing and as wagoon said tuned for one is not tuned for all.

 

What are you planning on revving the car to?

 

Can you add a photo of the exhaust collector? It is pretty importing seeing as you have a reaSonable sized exhaust.

Share this post


Link to post
Share on other sites

Based on who's theory? It is the most studied and proven arrangement for a 6. 6-3-1 are more questionable in this regard even though HP has been made with them.

What size tube are they (diameter of primaries and secondaries)? That's the most important thing and as wagoon said tuned for one is not tuned for all.

What are you planning on revving the car to?

Can you add a photo of the exhaust collector? It is pretty importing seeing as you have a reaSonable sized exhaust.

Just the size of the pipe? And I'll be reving it to around 6500

image.jpg1_zps5ecjq5af.jpg

What happened to that car? it was that tough looking black XF ute

He's a local guy and its a nice clean looking ute...

Share this post


Link to post
Share on other sites

... 6-2-1 so scavenging isn't going to be the best...

Based on who's theory? It is the most studied and proven arrangement for a 6. 6-3-1 are more questionable in this regard even though HP has been made with them.

 

Based on the theory that 6-3-1s are more expensive and complex than 6-2-1s, so if the latter is superior to the former, why would they bother? My personal take on it is that 6-3-1s are like 3 lots of 2-cyls each 360 deg apart. So a pulse from one scavenges another at exactly the same phase on each pairing of pipes. On a 6-2-1, a pulse from one pipe scavenges the other two at relative intervals of 240 and 480 deg, and only one of the other two cylinders can benefit from the pulse.

 

So the scavenging effect is halved on a 6-2-1 and occurs both earlier and later either side of that on a 6-3-1. This could actually be of benefit on a higher rpm engine where timing the pulse earlier would have a more suitable resonant tune than that of a 6-3-1 system.

 

I would say 6-3-1 for midrange, 6-2-1 for top end (if they are sized to flow enough). You might only be talking about 5 hp difference.

 

All this is pure conjecture and neither I nor anyone on here has back-to-back dyno results to compare both types on the same engine, notwithstanding the possible differences in what design might be suitable for a particular engine tune.

 

I call bullshit on any statement about tri-ys on a V8 being for scavenging. No cylinder is in phase with the one paired with it. The only truly scavenged set-up on a V8 is one paired like that on a Ford GT40.

 

The bottom line is that any extractor design is better than a manifold. I'm sure this set shown here will do everything expected of it.

Share this post


Link to post
Share on other sites

Best not to say someones thing won't work if all you have is conjecture (I am not try to be a jerk here Greg, just don't know how to word that more friendly, haha).

 

Mainly the pipe size Trent, the length matters, but is far less important than correct diameters. The collectors are important as well so we really need to see the exhaust collector.

Share this post


Link to post
Share on other sites

Best not to say someones thing won't work if all you have is conjecture (I am not try to be a jerk here Greg, just don't know how to word that more friendly, haha).

Mainly the pipe size Trent, the length matters, but is far less important than correct diameters. The collectors are important as well so we really need to see the exhaust collector.

Ok I'll measure them tomorrow and take some pics, thanks for the help so far..

And if I don't use them they will be up for sale..

Share this post


Link to post
Share on other sites

Another thing I have been told is the secondaries need to be the same volume as the primaries, so the secondaries need to be quite long on 6-2-1 where as the 6-3-1 can have much shorter secondaries as each secondary only has to have the volume of 2 primaries. This volume equation has to do with how the exhaust works to enhance the engine. So looking at the extractors that tpak put up they would have closer to correct volume ratio than the ones Trent put up. But they still may not be ideal, you need to calculator the internal volume of each pipe take the mean then see if they match.

 

BUT the most important thing to remember is what Greg said, we are talking about extracting the last 5% of power out of your engine using the exhaust. So if your not bracket racing or class racing where you need every horsepower down to the last 1/2 HP then it really doesn't matter and it will all be better than the standard setup. Everyone can argue over the best this or the best that but at the end of the day unless you plan on spending 50 grand on an engine to win a championship and have the best of everything else and you have spent 400-500 grand on your car setup, any extractors and larger volume exhaust will beat the standard cast manifold and pea shooter exhaust.

Share this post


Link to post
Share on other sites

 any extractors and larger volume exhaust will beat the standard cast manifold and pea shooter exhaust.

 

Line hook and sinker right there! the standard exhaust/tailpipe is smaller than the primary throat of the weber carb! anything over 3600rpm on a stock motor is just volume control with the stock exhaust on

Share this post


Link to post
Share on other sites

No doubt they will work. But doesn't hurt to evaluate, only Trent knows how far he wants to go and he has asked for an evaluation, so best we give it.

 

That volume rule, is only kind of a rule (it is not the underlying mechanism by which extractors work), that so happens to work in some instances. Ando follows it and it works for him (and I have no doubts with respect to what he does, he is on the ball), but I think if you varied the configuration of the extractors it would likely not stay true (I do not intend to try it). This is not about battling 6-3-1 and 6-2-1 anyway. The extractors in question are 6-2-1 and that doesn't make them either good or bad.

Share this post


Link to post
Share on other sites

And if I don't use them they will be up for sale..

I better tell you they are crap and buy them cheaply then, haha.

 

I am keen to see what the sizes are, and hopefully they match what you want. Sounds like a big engine in the way (6,500rpm is a lot!!!)

Share this post


Link to post
Share on other sites

I better tell you they are crap and buy them cheaply then, haha.

I am keen to see what the sizes are, and hopefully they match what you want. Sounds like a big engine in the way (6,500rpm is a lot!!!)

Aha, my car has ceramic coated ones on it atm...

But brought these cause they look pretty cool..aha

Yea gets to 6500 pretty easy but keen on getting it dynod... That's why I'm asking now instead of after..aha

Share this post


Link to post
Share on other sites

 

Not sure what they are as the tag was missing when I got them (just had the welds each end)

 

 

they are Genies, I have a set as well, they aren't bad and sound good! specially with a cam

 

Genies are great performance-wise, and sound tits but they use thin-wall tubing that fucks out in a few years. I'll never buy them myself. Needless to say... Never wrap them if you want them to last.

Share this post


Link to post
Share on other sites

Line hook and sinker right there! the standard exhaust/tailpipe is smaller than the primary throat of the weber carb! anything over 3600rpm on a stock motor is just volume control with the stock exhaust on

Quite true but anyone going to the trouble of getting tuned length extractors that have the size of primaries these ones do cant be running stock engine. Hence the statement.

 

And I do know that it is an idea for the volume but it was actually explained to me by 2 completely seperate guys that I trust and are very good at what they do, and neither of them was Ando. But yes Ando was the first to mention the volume of secondaries to me.

Share this post


Link to post
Share on other sites

While I do love dicussion and disection of ideas and theory's I found that after reading and only scratching the surface of the topic, very quickly you go from basic concepts like volume rule (which is only basic calculaton not a basic concept) into complex calculation requiring measurements that just cant be made unless you own a lab or major proffesional race team. I realised that it was good enough to use the basic rules because at the end of the day practical application needs to be the bench mark used. For example manufacturing tolerance does not allow for precise calculation to be made on volume if you can measure the difference in diameter with a set of verniers which is only a basic hand tool. Also things like distortion through welding and quality of steel used has an effect on finished product which all needs to be measured and controlled. And this is only optimising the basic volume rule, trying to measure gas expansion at given temperature and heat is just impossible.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×