thewird

iTrader: (8)

Are there any advantages to going from 2.5" to a 3" intercooler piping? I currently have a Pettit Coolcharge 3 style intercooler like so... and was wondering if creating new endtanks with 3" piping as well as cutting the greddy elbow to be 3" would be worth it? I have a 500R-SP that I plan to take to 25-30 PSI with methanol.



thewird

arghx

iTrader: (3)

i've been thinking about this as well. It seems like there is no point in going to intercooler piping that has a bigger inner diameter than the inner diameter of your turbo's compressor outlet, or the inner diameter of the Y pipe for twins. It would just slow down the air. But maybe more knowledgeable people can chime in.

thewird

iTrader: (8)

Hoping someone with experience or possible theory will pitch in.

thewird

thewird

iTrader: (8)

Probably should have used a more recent picture...



thewird

Dudemaaanownsanrx7

iTrader: (23)

I saw some testing done on a car, that wasn't a rotary and they lost a small amount of power going with 3" piping. They did 3 combination's, 2 1/2" to and after the intercooler , 2 1/2 to intercooler and 3" after, and 3" to and after intercooler. All the dyno results were pretty close to each other within like 5 or so HP. IIRC the 2 1/2" -3" combination had the best results and the straight 3" had the lowest results. Which was a surprise. They speculated that the increased flow from 3" piping didn't allow as much heat to be removed from the intercooler. Not to mention there would probably be a little more lag from extra volume being filled.

I think the benefits of different piping sizes will depend on the whole setup and is probably not worth the additional work. Keeping the piping as smooth and short as possible is probably where you will gain the most. And if the system has alot of sharp bends the 3" piping may be of more benefit. It seems having larger piping then the turbo outlet wouldnt be of much benefit, as the turbo would be the bottle neck for the system.

If you do decide to change everything you should try to get before and after dynos, as this is something i have wondered as well. I decided to use 2 1/2 piping as the route i wanted to take wouldn't allow 3" piping to fit and i figured the more direct path would be more of a gain.

Dudemaaanownsanrx7

iTrader: (23)

Taken from another forum.

"by the way, .4 Mach is the point at which air becomes turbulent and losses in efficiency start to occur exponentially. The key is to stay under that speed. You want to use the smallest piping possible that still flows enough to meet your needs. Larger than necessary piping increases lag time with no measurable gain"

Also to convert from Lb/Min to CFM for the equation below, you take the flow rate in Lb/Min for your turbo and multiply it by 14.27. That will yield the CFM flow for your setup.

arghx

iTrader: (3)

Here is something to consider, again regarding the inner diameter of piping. My Garrett T04S turbo with 2.5" outlet had the same inner diameter as the 2 1/4" piping that came on my 2nd gen Greddy FMIC kit. When I bought a Garrett T04R it had the same size outlet (2.5") but the inner diameter was larger, which is why I will be going with bigger intercooler piping now.

fendamonky

iTrader: (6)

Also, piggy-backing off of Dudeman's quoted chart. To find what your ideal cfm will be, multiply your desired BASE horsepower by 1.5. That will give you an approximate value for max airflow.

I just started reading Corky Bell's book (Maximum Boost) so I've not grasped all the concepts fully, but that's how it looks based off what I've seen so far.

Dudemaaanownsanrx7

iTrader: (23)

^^ interesting. is that for rotaries, pistons, or either? it seems about right i think. given that formula a 500 hp rotary would be flowing about 750 cfm. I don't know if that's right but if it is that would put the mach at .32 for 2.5" and .23 mach for 3" piping. both of which are lower then the .4 max for turbulent air. Another thing to consider is the mach ratings are for straight pipes so the more bends, the lower the turbulent mach rating will be. So a setup with lots of bends will need to keep the mack rating lower. Maybe .35 or something.... just pulling a number out of the air.

thewird

iTrader: (8)

So assuming that book is right and considering I'm aiming for ~600 BASE (flywheel) horsepower which would put me at 900 cfm, I might want to consider 2.75" piping then instead of 3"?

thewird

fendamonky

iTrader: (6)

Honestly my only complaint with the book so far is that there is no mention made for rotary engines one way or another... I saw one instance of a rotary, one of the pictures for a air/water intercooler was of an FC. Otherwise... nothing is mentioned what-so-ever to either support that equations would work the same for rotaries, or to point out that a different approach would be required.

It *does* specifically point out that going bigger is not necessarily better, since smooth tubing and gentle bends (that are large enough to flow the required cfm) will work just fine. If you go with too large of a pipe you will only really add to the volume of the IC, which isn't always good (which I think you pointed out earlier).

Additional bends will detract from overall efficiency regardless, so will having bad connections between pipes resulting in turbulence and loss in efficiency. It seems that every 90 degree bend takes 1% of the overall efficiency.

fendamonky

iTrader: (6)

Yes.

I would focus more on ensuring that the interior of the piping is as smooth/straight and seamless as possible (minimize distance between hard pipes inside couplers, avoid exaggerated lips, etc) basically anything which could cause terbulance.

thewird

iTrader: (8)

Ok, thanks guys, I have a better idea of what I'm looking for to make my choice.

thewird

Dudemaaanownsanrx7

iTrader: (23)

Cool let us know the results. It's an interesting question to think about that's for sure.

EZFD

I have a coolcharge III with 2.75" piping and it seems to work well with a GT4088. You should get great results with the 500r at that much boost. Are you going to run straight meth or meth/water mix?

thewird

iTrader: (8)

100% straight meth, I'm not playing games

thewird

EZFD

Good choice at 25-30 psi. What are you running for engine management and ignition?

JDK

iTrader: (8)

I think your piping is already 2.75,with the IC inlet & outlet being 2.5....So just open up the cooler itself to 2.75, Don't ask me how I know.....

thewird

iTrader: (8)

Thats because its the Rotary Dynamics intercooler kit :P. You told me it was 2.5", you got me confused now. I need to go measure lol.

thewird

thewird

iTrader: (8)

Didn't notice your comment until now... I run a PowerFC and am going to use the 2nd generation FJO methanol AI kit. I have an HKS twin power as an ignition amp. The demand on the ignition system isn't as bad with straight methanol, as it is with straight water or a mix, so I'm presume this will be enough ignition. However, if I do have breakup, I will upgrade to something stronger.

thewird