Racing Dynamics m20 e30 headers

[tinkwithanr]

You did not correct anything;

The MSDS headers are bigger and a shorter shot out vs the smaller RD headers. I can see the gain to long tubes, but these are not long tubes.

So again, what is the point of the extra cash for a smaller header?

From your ending quote, I gather it is just to have it etc. Nothing wrong with that.

Without getting to far into the voodoo that is header design, there is definitely such a thing as 'to large' a header. You want to evacuate the exhaust gases from the port as quickly as possible, and if your runners are to large it will slow down the velocity of the charge. So to just say that the MSDS must be better because they are larger isn't really truthful. Also, compared to the MSDS, the RD headers are much longer which can be beneficial, the collector is more gradual as are the bends leading up to the collector, and they are equal length.

You can tell that a lot more design went into the RD headers, whether it's worth it or not is up to you. For a stock engine the differences wouldn't be huge, but on a build engine where every last bit counts it could be noticeable.

[F34R]

The MSDS headers are going on a built 2.8 stroker. It will be dyno'd next year. I really want to run a stock manifold, then the MSDS setup to get a solid base of gains. I would REALLY love to dyno the RD ones too.

I can understand going too large will hurt the flow. Same effect with porting a head. I ported the head on the stroker that I built, so I believe matching the headers to the head will improve over stock.

Like stated above the 1.75 stock size is improved with the 2" RD collectors. But the MSDS headers are a PERFECT match to porting to head to the gasket opening. I dyed the edges and there is maybe 1mm overlap on the head(exhaust collectors are larger than head opening).

And anyone reading this PLEASE don't think I am bashing RD or saying anything neg about their product. There is no getting over how sexy they are.

I am personally all about gains and real world advantages. IMHO I would rather use the RD on a stock head. But the MSDS appear to have an advantage to a ported head.

What is the point to opening the head up if it is just going to cause flow blockage against the header collection? That is the very reason I ported to match the gaskets. And the gaskets match the collectors. In theory that would make a better flowing head.

Like stated above in my response, it is all about gains and real world numbers that you can see. So I will be posting a spread sheet in the future.

At the very least the RD ones will have a better throttle response and a better exhaust note. Right now I am taking Raceland mandrel bent M50 headers and fabbing them to work on my m20. Only difference is the flage sections that bolt to the head. They are a 2.5 collector as well, 304 SS and they have twisty collectors. So with a bit of cutting, welding you can have nice larger headers for under the price of MSDS ones.

If someone buys these please dyno your m20 before using the same exhaust system. Then again with the RD ones, I really would love to see the difference.

Same day before and after, on the same exhaust system.

[LJ851]

Without getting to far into the voodoo that is header design, there is definitely such a thing as 'to large' a header. You want to evacuate the exhaust gases from the port as quickly as possible, and if your runners are to large it will slow down the velocity of the charge. So to just say that the MSDS must be better because they are larger isn't really truthful. Also, compared to the MSDS, the RD headers are much longer which can be beneficial, the collector is more gradual as are the bends leading up to the collector, and they are equal length.

You can tell that a lot more design went into the RD headers, whether it's worth it or not is up to you. For a stock engine the differences wouldn't be huge, but on a build engine where every last bit counts it could be noticeable.

The MSDS headers are going on a built 2.8 stroker. It will be dyno'd next year. I really want to run a stock manifold, then the MSDS setup to get a solid base of gains. I would REALLY love to dyno the RD ones too.

I can understand going too large will hurt the flow. Same effect with porting a head. I ported the head on the stroker that I built, so I believe matching the headers to the head will improve over stock.

Like stated above the 1.75 stock size is improved with the 2" RD collectors. But the MSDS headers are a PERFECT match to porting to head to the gasket opening. I dyed the edges and there is maybe 1mm overlap on the head(exhaust collectors are larger than head opening).

And anyone reading this PLEASE don't think I am bashing RD or saying anything neg about their product. There is no getting over how sexy they are.

I am personally all about gains and real world advantages. IMHO I would rather use the RD on a stock head. But the MSDS appear to have an advantage to a ported head.

What is the point to opening the head up if it is just going to cause flow blockage against the header collection? That is the very reason I ported to match the gaskets. And the gaskets match the collectors. In theory that would make a better flowing head.

Like stated above in my response, it is all about gains and real world numbers that you can see. So I will be posting a spread sheet in the future.

At the very least the RD ones will have a better throttle response and a better exhaust note. Right now I am taking Raceland mandrel bent M50 headers and fabbing them to work on my m20. Only difference is the flage sections that bolt to the head. They are a 2.5 collector as well, 304 SS and they have twisty collectors. So with a bit of cutting, welding you can have nice larger headers for under the price of MSDS ones.

If someone buys these please dyno your m20 before using the same exhaust system. Then again with the RD ones, I really would love to see the difference.

Same day before and after, on the same exhaust system.

All of this is pie in the sky dreaming without a dyno chart.

I have dyno'd some really ugly headers that made great power gains and beautiful headers that did not. Also, a lot of headers are designed to be larger than the exhaust port for anti reversion of exhaust gasses. Same basic concept as a stepped header.

[tinkwithanr]

Like LJ said, you normally want the exhaust port to be smaller than the header inlet to help with anti-reversion. I would hesitate opening up the exhaust port to much if you haven't already done it.

I'll have a dyno of my RD headers on my 3.2L M20. Sadly they are from the original production and not this run. The old pieces have a more gradual collector compared with these new ones.

[Bullet Ride]

The MSDS headers are going on a built 2.8 stroker. It will be dyno'd next year. I really want to run a stock manifold, then the MSDS setup to get a solid base of gains. I would REALLY love to dyno the RD ones too.

I can understand going too large will hurt the flow. Same effect with porting a head. I ported the head on the stroker that I built, so I believe matching the headers to the head will improve over stock.

Like stated above the 1.75 stock size is improved with the 2" RD collectors. But the MSDS headers are a PERFECT match to porting to head to the gasket opening. I dyed the edges and there is maybe 1mm overlap on the head(exhaust collectors are larger than head opening).

And anyone reading this PLEASE don't think I am bashing RD or saying anything neg about their product. There is no getting over how sexy they are.

I am personally all about gains and real world advantages. IMHO I would rather use the RD on a stock head. But the MSDS appear to have an advantage to a ported head.

What is the point to opening the head up if it is just going to cause flow blockage against the header collection? That is the very reason I ported to match the gaskets. And the gaskets match the collectors. In theory that would make a better flowing head.

Like stated above in my response, it is all about gains and real world numbers that you can see. So I will be posting a spread sheet in the future.

At the very least the RD ones will have a better throttle response and a better exhaust note. Right now I am taking Raceland mandrel bent M50 headers and fabbing them to work on my m20. Only difference is the flage sections that bolt to the head. They are a 2.5 collector as well, 304 SS and they have twisty collectors. So with a bit of cutting, welding you can have nice larger headers for under the price of MSDS ones.

If someone buys these please dyno your m20 before using the same exhaust system. Then again with the RD ones, I really would love to see the difference.

Same day before and after, on the same exhaust system.

The only reason the shorty headers are better than the stock cast manifolds is because they are lighter and they look pretty. Other than that they aren't going to do much for you in terms of performance. A set of long tube headers is going to give you more "real world advantages" than a set of shorty headers will any day of the week, regardless of what you've done to your head.

[F34R]

That is pretty much my very thoughts, they are very pretty.
And no, I left the head smaller than the manifold collectors. Would be dumb to open them up beyond the collectors, like you mentioned above.

I tried to find him long tubes, but they were all beyond his budget of 450. MSDS fit the bill perfectly.

And yes, I am doing all this to see if there is real world gains. I just wish the dyno was close enough for a stock pull. There is plenty of stock pulls though, I will just find a fresh rebuild to go off of.

[tinkwithanr]

I think bullet was referring to the fact that the MSDS headers are a 'shorty' design, hence you probably won't see much gains over the stock manifolds. They are just lighter and prettier than the stock cast iron manifolds. The RD headers are a much better design all around, and will show better gains on a stock OR modified engine hands down.

And no, I left the head smaller than the manifold collectors.

By collectors do you meant the header primaries? The collectors are the area where the individual tubes merge together into one larger tube. And I thought you said you ported them to be equal?

That is the very reason I ported to match the gaskets. And the gaskets match the collectors. In theory that would make a better flowing head.

What I said above (along with LJ) is that the tubing on the header is normally larger than the exhaust port on the head. This is done to help prevent reversion of the exhaust gases. A more thorough explanation can be read here:

http://www.circletrack.com/enginetech/ctrp_1011_race_engine_reversion/viewall.html

From the same article, here's some info on proper sizing of the primaries:

"Reversion Effects From a Restrictive Exhaust System
Generally speaking, as backpressure is allowed to increase (largely based on header primary pipe size), cylinder pressure at the point of intake valve opening will correspondingly increase the energy level of reversion pulses delivered back into the inlet track. There is a balance that needs to be struck between primary pipe size to effectively improve the exhaust "blow down" period and proper cylinder evacuation. This becomes particularly critical during mid-rpm operation where over-sized headers provide insufficient flow rates for good cylinder cleansing of exhaust gas. Think about the time when smaller primary pipe size improved mid-rpm power with little or no attending loss at higher engine speeds. Reports of such observations among engine dyno operators are quite common."



For the record I hope the above doesn't sound like an argument. I just wanted to expand on what I brought up before and explain it in more detail. I feel that there was some miscommunication and wanted to clear it up.

[firemanory]

Frank, any update on your ass dyno? Any possibility of having a true dyno run? Might help move them if the numbers turn out nice.

[SkiFree]

Basic terms .... picture the exhaust leaving the open exhaust valve through the head and into the header. The piston is obviously traveling downward. Near the end of this stroke the exhaust valve will momentarily still be open and the piston will actually start to suck exhaust back in. The step from the exhaust port and the header prevents/obstructs this backwards flow.

Another side note is I'm under the belief that most exhaust gaskets are sized roughly half-way between the port diameter and the header primary diameter. So if you are running a more aggressive cam there are gains to be had by port matching to the gasket (but of course verifying the gasket size first).Tink is right with the reversion.

[fporro]

Trying to get a running stock-ish m20 to test them on by Castro's dyno day event...

http://www.r3vlimited.com/BOARD/showthread.php?t=268013

So far my butt dyno approves of them,
Biggest difference it's a second ramp-up from 3800 to 4600 rpms whereas ss copies did well from 2800 to 3500 rpms, beyond that it felt flat.

Lower noise level on engine bay too.
Muffler tone it's a bit deeper

there's less vibration at engine bay too.

[fporro]

not the best audio quality but you get the idea ...

[firemanory]

If you can somehow wrap the microphone with some foam or fabric, it will help to reduce the wind noise, which should help bring the header sound out more.

I would love to get a set, but for me gain numbers would definitely help seal the deal.

[fporro]

I'll try that, windows were rolled up, think cabin noise only.

Chris, at Castro motorspot will test a set this weekend during their dyno shootout., we will post those numbers as they come up.

My car has itb's, no cats (resonators) and a maf conversion, so my hp output would not be a fair readout.

[firemanory]

I'll try that, windows were rolled up, think cabin noise only.

Chris, at Castro motorspot will test a set this weekend during their dyno shootout., we will post those numbers as they come up.

My car has itb's, no cats (resonators) and a maf conversion, so my hp output would not be a fair readout.

Did they get to do a dyno run??

[fporro]

Not sure yet, I'll contact Chris after holidays.

Melekalikimaka from Sheraton Waikiki :)