Has anyone actually dynoed the drag 5 reeds vs the seven petal reeds?

[LakeFever]

I read everything I could find and saw opinions going either way but some of these discussions were in very old threads. So I’m wondering if over the years anyone actually ran the same motor on the dyno back to back comparing the big 5 reeds vs the 7? Or maybe has some other test data they can share to suggest which was superior and why?

[KIRCHNER]

i did a bunch of research, the difference wasnt worth turning a wrench for. my conclusion.

[LakeFever]

So both are good to go ain’t nuthin but a coin flip difference. Well good to know either or is champ

[NICE PAIR]

you have less reeds to break in the 5 set!

[LakeFever]

I really like my four petal motor and the five is the same shape just one extra wider. It’s got my vote on aesthetics alone. My brain looks at things visually and to me the five also has less block in the airflow path. Two less vertical blocks. Seems like it would be better. I guess mercury liked them too because they replaced the seven on the ros motors.

[XstreamVking]

Yes there was a Dyno test with different reeds. Same cages I believe. Can't remember who did it. I think Chris Carson was saying that the 5 petal was the best all round. 7 was a tick better above 7500 r's. Not many need to turn over 7500.

Here's t-rex's thoughts...

Earlier merkz had 5 peddles in thier fish'in motors, 14 in the hi-po'z...newer motors now have the rubbercoated 4 peddles(that replaced the 5 peddle) in fishing motors...U kan replace the 14 peddle Hi-po'z wit the rubber coated Jet drive units (5 petal)...On a river motor(HP bassbote etc) the 4 peddle units are better than any...they flow a lil better than the 5 peddles, but seel better for better bottom/idle/midrange, and may even add a lil top end rpm...Reed material???? Opens a new can ov wormz...I have tried them all, even cut my own the way I figgered would be better for my application...On a 200 2.5, stock, 93' fishing motor, the best performing reed I run on it wuz the original steel ones!!!...I run dual stage glass, single stage glass, carbon fiber(worst ov all), and 1 solid glass reed...bottom end and idle would change a lil bit from reed to reed, but the steel had the best all round performance ov all tried...Now, for safety, glass iz better...I turned the stock 200 in excess of 8000rpm wit the steel reeds(1:87 w/20"yamaha)...I have also changed from a 5 peddle to a 14 peddle front, and lost performance(fishing motor)...On a highly modified motor, a 14 peddle will give that extra flo on top(over 8000-8500) rpm...If your operating range iz below 8000rpm, the 5 peddle(4 rubber) will out perform the bigger cages, because of the enhanced low/midrange punch(higher air velosity)...EFI motors seem to utilize the bigger cages a lil better, but the smaller ones are allround better for the river/bass botes...I also find the single stage glass reeds to be better than the dual, and the 2 finger reeds on a 4 peddle cage to be better than the seperate finger ones...OK, Let the argument begin!!!...REX (13)

[KIRCHNER]

whats a duel stage reed?

[LakeFever]

Yeah I read that Trex post in my digging. He’s a great resource and wha a character! I’ve never had the pleasure of chatting in a thread with him but his influence ran strong on my first build with my plan to stick with the four petal cages. They work great im pleased but im in pursuit of more power and the main difference between a trex build and what im going is efi. Most of trexs builds were carb. With carbs you really want a strong vacuum signal to keep the carb happy flowing fuel. With efi squirting fuel on command this isn’t so big of an issue. My four petal is not turning the kind of rpm I’m after so I’m stepping up to most likely the 5 for above reasons. It will be interesting to see because I’m doing all the same porting mods as my first build plus a little more. Going deeper in the chest cuts and porting the sleeves out too. Probably a powers slide and ecu in front of the big five petal. Top it off with a lightweight flywheel 16amp conversion. That’s the general plan we’ll see how it goes. Still learning so the plan might change

[XstreamVking]

Kirchner, look up boyeson dual stage reeds and check them out. They have their supporters. I have ran them and they were real smooth. No performance gain noted though.

https://boyesen.com/c11651-performance-reeds

[LakeFever]

I’m very pleased with my TDR reeds. Another reason I think I’m going to the big five is apparently Merc used a composite reed for them so no steel to break and eat up a motor

[CI STV]

Been pondering this move myself from a while back. May have even posted on here about it, IIRC.
I’m currently running the Merc 5 petal rubberized “Sportjet” cages with PPE carbon reeds. I have a set of Buckshot billet 7 petal cages and a couple of sets of Boyesen dual stage reeds that I want to test.
Just haven’t had the ambition to test them yet though.
‘Everything I’ve found suggests it’s not worth the trouble.

A few things to note:
- The 5 petal Sportjet cages are expensive, although they come with a good set of composite reeds attached. You can probably buy a couple of sets of billet cages with boyesen reeds for the price of one set of the 5 petal cages.
- The rubberized cages are presumably easier on the reeds, but they have less screws holding them, so I think it’s harder to get a set of aftermarket reeds to sit flat on them. Had to fiddle around with mine a lot to get them to lay down perfectly. The screws are very small too, and very easy to strip (don’t ask how I know).
- In theory (not mine) the billet 7 petal cages with the dividers straighten out the air going through the cages, which should aid air flow into the crankcase. But you know what they say about theories…
- As far as I can see, you can’t use dual stage reeds on the 5 petal cages. But I’m not sure the 2 stage would make any difference on them anyhow, in terms of horsepower gains, compared to a good set of composite reeds.

[LakeFever]

I completely appreciate the remark on the fiddly comment with regard to installing the reeds flat. I spent the better part of a day blocking and fitting my four petal reeds up. The screws are so tiny I’m always worried it’s either going to snap or not be tight enough and fly out one day.

The theory of the air straightening is interesting. I’m thinking Smokey Yunick here the only way to know for sure is to flow them and smoke them to see. I don’t have a flow bench or a smoke machine so I’m going to have to go on gut here. That always makes the most power right? I had a couple cars dyno tuned at this race shop and painted on the floor in front of the dyno it says “the bull **** stops here” which always made me chuckle.

Still all that aside this is a lot of fun making guesses and sharing thoughts on the best build plan. Good thread