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Thanks so much guys for the detailed responses - makes perfect sense now. I really appreciate it.

I'm hoping to jump to straight to a 102, ported blower, cam, and possibly headers setup (+all the cooling and fueling mods) after the rainy season in California. Just need to figure out how to build the setup to work as good as possible with 91 as I don't have access to E85 in Norcal.

Thanks,
Jason

Jason,

So you don't have to read a page of babbling- For HPDE the more power you make the hotter IATs will get... Period. For the road course porting the blower is one mod that has little penalty from a heat perspective. I'd port the blower and put on a 2.8 pulley. The car will make the power of a 2.4/2.5 pulley while keeping IATs notably cooler than that setup.

This advice is from a fellow Southern Californian who tracked an 04 Cobra for 5 years. I fully ported the blower on that car and with a modest boost gain the car made lots of power without going into limp mode on warmer days.
I hear you. I don't want to make 650rwhp on paper but 550 (or worse, 550 + boom) in real world conditions when my IAT2s are 150+ with a 2.4 or 2.5. Do you run a cam or headers and does that help with IATs?

Do you have a rear diff cooler that you recommend? I instructed my buddy in my car (I bought it from him after the track day) and even for a noob on his first track day he got a diff overheat message.

I also have a 1969 camaro with a widebody, full cage, kirkeys, a lot of brake and suspension, 500rwhp small block, and a 6 speed for track days, so the CTS-V is sort of a backup car for rainy days and when I break the Camaro.
 
Yes, I too grew tired of futile efforts make a heavy supercharged pig of a car handle and not explode in the heat, so I built an LS powered RX7 with brakes, suspension, kirkeys etc. 2600 lbs with 51/49 weight distribution and 400 WHP took care of all that.

I can't comment on cam/headers on the V specifically. I am sure the headers will reduce underhood temps if you coat them. If you didn't up the boost, and added a cam and headers I could see the car making good power with liveable IATs. There are some guys on here that have made it work, but it seems the fast guys have gone to NA engines. It just depends on how crazy you want to get.

There are a few diff coolers on the market, but making your own is probably the most cost effective.
 
Yes, I too grew tired of futile efforts make a heavy supercharged pig of a car handle and not explode in the heat, so I built an LS powered RX7 with brakes, suspension, kirkeys etc. 2600 lbs with 51/49 weight distribution and 400 WHP took care of all that.

I can't comment on cam/headers on the V specifically. I am sure the headers will reduce underhood temps if you coat them. If you didn't up the boost, and added a cam and headers I could see the car making good power with liveable IATs. There are some guys on here that have made it work, but it seems the fast guys have gone to NA engines. It just depends on how crazy you want to get.

There are a few diff coolers on the market, but making your own is probably the most cost effective.
I built the second or third CARB legal LS1 powered RX7 back in 2005 (FD). Was a blast with 400rwhp. I eventually moved up to a 280rwhp Ariel Atom that was spooky fast (1350lbs), but sold it to buy a house. Is yours a FC or FD?

Sorry for the thread jack...
 
I'm the biggest babbling idiot on the interwebs


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Whew!!! Glad to share the crown with ya buddy! Look - lots of chatter here but in the end, and for you as a vendor and businessman, just remember that some people will find benefit in this and some will not. I like that you focus on your pride and craftsmanship, producing the finest possible quality for those that want, need, and appreciate it. Don't sweat those that don't value the work - that's gonna happen and is no big deal. The best products are made by companies with singular vision and focus. Take Apple - they don't try to make cheaply priced products. They make things to THEIR standards and then figure out what needs to be charged to stay profitable. And plenty of people line up and camp out for days to get their next big iThing. I'm not one of them, but I love the customer loyalty they command. So instead of buying their products for a few hundred bucks, I own a shit ton of their stock.
 
I built the second or third CARB legal LS1 powered RX7 back in 2005 (FD). Was a blast with 400rwhp. I eventually moved up to a 280rwhp Ariel Atom that was spooky fast (1350lbs), but sold it to buy a house. Is yours a FC or FD?

Sorry for the thread jack...
Awesome! Mine is an FC with no CARB legality at all :) The car is really fun on track. I thought about an FD but consumables and replacement parts are much cheaper for the FC as you know. The next track car I build will probably be an LS swapped RX8.
 
Discussion starter · #126 ·
Not to be picky brother Karch, but "m" vs "n" in this case does kinda have specific and different meanings to me as a physicist.

But as you noted, and which I totally agree with - the laws of thermodynamics apply. It's often the case with situations like this that the simplified scenarios we were taught in 101 in college don't account for things like conductive heat, transfer heat from other components, and so on.

So the simple thing that Karch is after here - in the most basic form, is the relative relationship between compression and heat. Double the pressure, double the heat. So if you take a given mass of air and reduce it's volume by one half, it's absolute temperature will double. Don't use Fahrenheit - 30 degrees is NOT twice as hot as 15 degrees. Nor is Celsius. We gotta go hard core with Kelvin. Once you do that, you realize that the percentage difference in temps is not nearly as much as we think.

Example: 81 degrees F is about 300 Kelvin. 120 F is about 322 Kelvin. So the difference in total heat between 80F IAT2 and 120 IAT2, in absolute terms, is only about 7%, not 50%. But that's still substantial in engine world, right?

What Karch is expressing is called the "Ideal Gas Law", which merges together the relationships between temperature, pressure, and volume. VERY applicable to our FI cars and worth every member on here knowing at least the fundamentals of. Here's the basics, as concisely as TriTex can do:

1) If you change the volume, you change the temperature inversely. Compress a gas to half its original volume, you double the temp. Expand it by a factor of 2, the temp goes down by half.

2) Likewise, if you increase the pressure of a gas - without changing the volume, the temperature behaves in exactly the same way. Double the pressure in a fixed volume, the temperature will also double.

3) If you HEAT a gas, while holding the volume of space it occupies fixed, the pressure will increase. As before, proportionately. Double the temp (in Kelvin) and the pressure will also double. Remove heat and the pressure drops accordingly in the same ratio.

In Karch's example, you can see P,V, and T - which represent Temp, Volume, and Pressure. The other bits are there to make all the math work out and we can assume they are constants and/or extraneous for now - just to keep things uber-simple. But as you can see, pressure and volume are on one side of the equation, while temperature is on the other side. As long as you remember that increasing pressure increases temps and/or decreasing volume increases temps, then that's half the battle.

So how does all this academic crap boil down to superchargers and porting and shit?? Well as some have noted - perhaps porting increases the volume in some parts of the airflow path. By having a larger volume, perhaps the pressure is lower, which would also lower the temperature proportionately. But Karch - in his wisdom (or to his demise...we shall see!) cleverly included that lowercase "m" in his equation - which is the mass of the gas we are dealing with.

What is more difficult to figure out is just exactly how much of an effect the porting has on total airflow (which would alter the mass of air involved, and hence our equation results).

But in a very simplified view, all of the porting is "after" the rotors (save the snout I guess...). If you boil this down to pre and post rotors, we can talk about temperature, volume, and pressures before the intake gas is compressed (in the intake) and after it is compressed (in the blower lid and the runners, more or less.

If the porting creates substantial or measurable changes in pressures after the rotors, we might conclude that restriction into the heads has been reduced. And along with lower pressures we get a liner change in intake temps. But a sharp person might say, "But wait Tri - that gas has already passed the rotors, and you said lower pressures mean less mass, but conversely lower temps mean higher mass - aren't these effects kinda canceling each other out?"

And that person would be correct. Karch notes that thermodynamics can't be skirted. Once you have a given and fixed mass of air, that's what the engine is going to get. If the blower was forcing the air into the lid and runners faster than the heads can eat it, the pressure in the lid would just grow and grow until something bursts. But it doesn't. It quickly finds equilibrium.

So as you think through all this - and I am going to leave this post "Duck Style" for you to do some basic math if you aren't an engineering / propeller head type like me, Karch, and others - just remember that power is all about how much MASS of air you can stuff into the cylinder. More mass of air = more oxygen = more fuel you can burn with that oxygen = more power. Now heat DOES factor in, but in an engine, that heat is all about safety and not as much about power. If we had different fuels and infinitely strong components, we could dramatically change the heat points and get far greater power AND efficiency at the same time. Remember that an internal combustion engine is, at the end of the day, a simple heat engine - it does work based on the transfer of heat from one mass to another, imparting some mechanical force in the process. The first mass is the intake air, the second mass is the exhaust. All heat engines produce greater and greater power when the difference in temperatures between mass 1 and mass 2 are greater. That's fundamentally why cooler intake air is good. But hotter exhaust is also good - take for example an engine tuned for mileage instead of power. They run leaner and hence hotter - by leveraging a hotter exhaust temp, the engineer is effectively increasing the difference between intake air temp and exhaust temp, increasing power (in this case, power is traded for efficiency, but they are effectively the same concept - get as much as you can out of the fuel you have).

To get you guys started, let's re-arrange Karch's formula this way:

m = PV / RT

Why did I do it this way? Well - in our cars, we want MOAR POWAH! How do we get it? By maximizing the amount of air and hence fuel we can burn. So in Karch's equation, we want to get "m" as big as we can. You can do that by increasing the "P" or "V", or by lowering the "T".

This is where Duck needs to come in and talk about choke velocities and some more advanced concepts. Realize that Karch's formula is actually for static systems, not dynamic ones - but the core concepts are completely valid and good starting points. Duck and others need to bring in a few simple concepts around when increasing intake pressure does NOT cause a corresponding increase in the mass of air delivered.

And to bring my lengthy post full circle - THAT folks is what porting is all about - not about increasing volumes or even trying to optimize the pressure / volume / temperature relationship. Let's assume - for Jokerz sake - that we tell him we want to keep the volume of the lid, blower case, snout, runners, etc exactly the same - we only want him to change the SHAPE. A good porting job is about finding any point in the airflow path where the good old relationship between temp, press, and volume would get compromised. How about an example we are all familiar with?

Like, say, for instance that annoying little flow restricter in "water saver" faucets. They INTENTIONALLY put a precisely sized hole in a flat disk and installed that in your faucet. But what is really going on in your faucet? Well at the most simple level, that little hole is fully capable of passing all the water you need - without creating one of Duck's "choke points" - up to about 2 gallons per minute. Faucets use a type of restrictor called an "orifice plate" - you've seen 'em...just flat disk with a hole in the middle. But to illustrate my point about porting and how and why shape is so important, check out this video. Yes, it's VERY long, but just watch the first minute or two and you'll see something VERY interesting. The "choke point" in a system like this actually occurs AFTER the hole in the plate. Wait - what?!? You mean that little hole is NOT the point of greatest resistance, that it is actually downstream of the hole where the pipe is many, many times wider and more open? Yep - that's actually what happens.


So how does this apply to porting? Well - a good porter understands these very fine points about the flow characteristics of compressible fluids like air. Water, by comparison is also a "fluid" in physics terms, but is incompressible - so my previous example of water in the video isn't exactly applicable, but the point is that fluid dynamics isn't always intuitive. You can't always just use your intuition and logic skills to figure out how to port something - the physics matters and there's no way around that.

The porter knows enough about the nature of flow dynamics to know exactly where and how to change the shape of the flow path to avoid as many choke points as possible because we know these will muck with our beloved PV=mRT equation, making the mass delivered less. Ever wonder precisely why some cars make more power on 16psi of boost and others don't, even with the same cam and such? One way or another, its quite possible that even though both cars produce the same pressure behind the choke point, the flow after the choke point is reduced. The whole point of these flow restricting faucets is exactly the opposite of what we want in our cars - these faucets are designed to flow NO MORE than about 2 gallons per minute - NO MATTER HOW MUCH PRESSURE (i.e. boost) you put in the supply line going into the faucet.

The same principle used to choke off a faucet at a known rate of water flow can also choke off your engine. It flows just fine, right up to some magical-seeming cutoff. And what's effectively happening is there is some point in your airflow path that - no matter how much boost you use, just like the faucet is going to refuse to flow any faster.

Ok - I hope that was helpful to some of you out there and not too confusing. When you talk about porting - just remember it's not likely or even necessarily advisable to expect the porter to dramatically change the boost or other pressures in your system. His goal is to eliminate any point where your boost level is not producing the maximum amount of flow that is is theoretically capable of. How would I measure a good port job? Ultimately its not that hard - I would expect to see exactly the same peak boost levels, but with a greater mass of air flowing into the cylinders, with a corresponding increase in fueling needs and hence, power output. If the porting did not cause this direct and measurable effect, it means one of two things: 1) the porting job was not done right, or (hopefully), 2) Choke points are NOT a restriction in your build - so you can increase your power by adding more pulley, going with a larger cam, opening up the exhaust, and so on. All this talk about heat IS a valid topic, but its a good simplification when talking about porting to focus more on improving the mass airflow amounts at a given boost pressure. If you hold boost constant ("P" in Karch's equation) and the porting doesn't have much overall impact on the volume of the components, then ultimately the "m" or mass of air should improve.

Realistically, practical considerations mean its easier to remove metal than add it - but the SHAPE is what we are after, not enlarging anything.

Verbosely yours,

-=TriTexan=-
This might be the most epic, glorious post you have ever made on this forum.

Well done!

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This might be the most epic, glorious post you have ever made on this forum.

Well done!

Sent from my SCH-I545 using Tapatalk
I hope that's a GOOD thing... ;)


I'm never sure how much explanation is useful - some have different backgrounds and this sort of thing might be helpful. But to someone who is an engineer or scientist I may have taken some leeway that isn't quite precise or perfect but for the sake of simplification I paraphrased. Some would cringe a bit at the inaccuracies.

But if it helps folks understand and learn then I'll call it good. I don't always understand all the engine theory but I do appreciate when an expert in another field can put things in terms I can get my head around.
 
Whew!!! Glad to share the crown with ya buddy! Look - lots of chatter here but in the end, and for you as a vendor and businessman, just remember that some people will find benefit in this and some will not. I like that you focus on your pride and craftsmanship, producing the finest possible quality for those that want, need, and appreciate it. Don't sweat those that don't value the work - that's gonna happen and is no big deal. The best products are made by companies with singular vision and focus. Take Apple - they don't try to make cheaply priced products. They make things to THEIR standards and then figure out what needs to be charged to stay profitable. And plenty of people line up and camp out for days to get their next big iThing. I'm not one of them, but I love the customer loyalty they command. So instead of buying their products for a few hundred bucks, I own a shit ton of their stock.
Word. I'm not (yet) an active member here, but as a lurker I have come to really respect both Jokerz and TriTexan. Tri is right, far too many people focus on the 5% on the fringe that make too much noise/drama, but a lot of us find the professionalism, dedication, results, and sense of humor of people like Jokerz to worth investing in as we build our rigs.

Cheers,
Jason
 
Word. I'm not (yet) an active member here, but as a lurker I have come to really respect both Jokerz and TriTexan. Tri is right, far too many people focus on the 5% on the fringe that make too much noise/drama, but a lot of us find the professionalism, dedication, results, and sense of humor of people like Jokerz to worth investing in as we build our rigs.

Cheers,
Jason
Thank you sir. I think Jokerz and I both believe in doing the right thing even when others are cutting corners or maybe just not taking the time to deliver at the same level...

You'll never regret taking that approach and over time your reputation will pay you back in full.
 
Word. I'm not (yet) an active member here, but as a lurker I have come to really respect both Jokerz and TriTexan. Tri is right, far too many people focus on the 5% on the fringe that make too much noise/drama, but a lot of us find the professionalism, dedication, results, and sense of humor of people like Jokerz to worth investing in as we build our rigs.

Cheers,
Jason
Image



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There's a reason why as soon as I was on this forum, even before I purchased my V, I contacted Brett about starting a vendor-ship here.

While I had my Lightning from 09' - '14, I watched Brett on the forum, slowly but surely, start porting here and there to eventually running off every other porting vendor because the amount of data, testing, and real world numbers he was able to provide was unmatched. Not only on the Lightning forums but I saw his ports start popping up on Termi's, GT500s, and even a Marauder or two.
 
There's a reason why as soon as I was on this forum, even before I purchased my V, I contacted Brett about starting a vendor-ship here.

While I had my Lightning from 09' - '14, I watched Brett on the forum, slowly but surely, start porting here and there to eventually running off every other porting vendor because the amount of data, testing, and real world numbers he was able to provide was unmatched. Not only on the Lightning forums but I saw his ports start popping up on Termi's, GT500s, and even a Marauder or two.
Don't forget the gun talking is pretty much what led to this

This guy made me buy a $2400 ar-15.

Trust a man you can talk guns with all day everyday!!!




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Don't forget the gun talking is pretty much what led to this

This guy made me buy a $2400 ar-15.

Trust a man you can talk guns with all day everyday!!!




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Hell yeah!

Don't forget how much money you've made from guns with my help too!
 




Colder Dyno day

To warmer Dyno day

Picked up 30 hp and 11 ft lbs

This was the test he Dynod in colder weather with stock blower

Then Dynod in warmer weather with a ported blower

You see the gains from colder to warmer Ed still 30 hp

Now this test was with aggressive knife edge runners




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Absolutely.

Personally, and I don't have data to back this up, yet, but I think on a car that has ported or aftermarket heads, decent sized cam with lift to take advantage of the heads, I would expect 30-40 hp from a well done blower porting.

But, honestly, people tend to not look at the torque numbers, but I think the more substantial gains are in torque values from 3000-5500 rpm, beyond that the 1900 starts to run out of air.

The VE gains, I anticipate, will be pretty impressive.


Sent from my local E85 station.
 
I'm starting to think of a few more ideas but it involves cutting and welding in a custom inlet completely

Anyone have any measurements between the block and bottom of the blower


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