Max,

If memory serves me right I lost all of my engines due to detonation in the rear rotor. That is a 4 outta 4 times.

It might be better to restrict air to the rear rotor when it appears that the rear rotor may be the least efficient in letting heat out.

 

Interesting stuff. As always, let's see the dyno results! Unfortunately, I've been saying that about the freakin' Camden supercharger in the FC Specific forum for months now

 

if anyone read the rxtuner issue that has "the perfect FD" written on it you would have come across the article that explained that this guys so called perfect fd was not perfect because his rear rotor ran 250 degrees hotter than the front rotor...now i know thats an odd problem...so it might just be true that the lim does have different flow rates. For this mans rear rotor to be running 250 degrees hotter...to me it seems like the rear ports on the lim are more limiting possible....maybe the slower the air flow the less movement it has from the hot engine? possibly. So maybe the air's slower flow rate is causing it to rise in temperature due to its low velocity. I mean there has to be a reason for this mans rear rotor to run 250 degrees hotter than the front so i guess this company has concluded that the lim is the culprit. Anyways, my guess is the lower any kind of air temperature is for a car is deffinately going to increase horsepower...so either way i think this manifold will be a good buy if it can lower the rear rotors egt increase. well does anyone have any thoughts about my babbling?
Thanks and peace out

 

oh yeah sorry abuot the shitty english, i am studying for a huge chem test to keep my scholarship.

 

With the (1) injector per runner setup on that, would u completely eliminate the primaries?

 

Probably would be there for more fuel/HP

 

You probabily could, but I think its there because in their car, running 30something PSI, they need more fuel and thats a perfect way of delivering it.

 

you'd probably still use primaries, also, may be possible to more easily facilitate a direct-port nitrous setup easier with these extra bosses

 

Interesting indeed. Hopefully these will work with the BNRs.

 

I did this already but I didn't put in totally new runners just honed out inside
I'm sure that one flows better?

http://plaza.ufl.edu/yanni25/7work/LIM%20WPH/IM000467%20(Small).JPG

 

Could it be possible that the rear is small er cause its shorter? If you look at Surge's pic the rear sec goes strait down, but if you look at GZ LIM its equal length. Would this be the reason? Just throwing more facts/possiblites out here. Maybe they made it smaller to compensate for it being shorter?

 

I saw this at sevenstock and talked to the guy from Ground Zero about them a bit. I am pretty certain he said you couldnt use it with the twins because of fitment issues. There is also no way to keep your emissions.

 

Hmmm... maybe I've got it backards about the rear secondary not flowing as well as the front secondary -- the rear secondary looks like a straighter shot in that pic of the stock LIM. That might explain the +250 degrees on the rear rotor, too, if it was running lean. However, running rich can reportedly give you some hot EGTs as well. Now I'm confused about which secondary runner flows better on the stock LIM...

-Max

 

I'll drop Ralph a PM and ask him to check this thread out. CJ

 

The reason for the hotter EGTs is caused by leaner air/fuel mixtures. Im pretty sure it has to do with the way the air flows through the intake elbo. If you have air flowing at a fast rate into a turn, chances are the air is gonna be flowing more dense along the outside of the turn (like in centrifugal force), and in turn there is more air flowing toward the back end of the manifold, resulting in more flow to the rear rotor. I could be wrong, but this is how i make sence of all of this. I dont believe there is much if not any difference as to the volume or flow rate for the front and rear halves of the LIM.

The best way to fix the problem would be to either restrict the rear part of the LIM more, or unrestrict the front part of the LIM to even out the amount of air that passes through.

If this product works like described, it would most definately result in lower EGTs and could possibly be another way to prevent detonation in our motors. It also makes easier fine tuning, and should result in more power.

Anybody up for a big group buy, if the price is right???

Adam

 

I'd like to know how the guy tested EGT for each rotor to back up the +250 claim.

Tim

 

Well the only way i could think of would be with a single turbo and have an egt guage in runner to the turbo but still, the heat would disipate and share some temps.

 

I'm under the same impression as "fastcarfreak". I've always understood that the rear runs leaner and hotter than the front and also that it was because of the elbow not the lim. Now....if the rear runner does flow less it could be because Mazda was trying to make up for the extra O2 than the rear gets because of the turn in the elbow.

I think this would be a great lim, but it seems like it should be in conjunction with a new uim that has a large tube style plentum so that the air equalizes better before going into the lim.

just my .02, I'd be very interested to see some datalog sheets of A/F and egt in each port at the same time so that it can all be compared accurately.

Stephen

 

Max don't use this picture to compare sizes of the runners because we added a lot of filler to the last runner on the left to cover up the emission holes and then for an artistic touch shaped it.

Yanni

 

Other then this new LIM, i think the only other way to fix the rear rotor running leaner problem would be to have a fuel management that can control the injectors individually. This way you can add more fuel to the rear rotor to compensate. The only problem i see here, is that your rear rotor will be working harder then your front rotor. I think i would rather my 2 rotors work at the same level of performance. After I see some info from people on the forum about this new LIM, showing that it actually works, i definately think i will be picking one up.

 

Acouple of months ago I discused this with some of the guys from pettit. From what I understand is the rear intake runner is Quite abit shorter in length, actually they are all different by a little, the rear being the worst. this would cause the rear to run on the lean side because it would be getting a better (sooner) flow of air, thus causing higher egts. The thought that air would be denser around the backside of the UIM because of the intake elbow radius would only multiply this problem. To add to the problem most of us have better flowing intakes and exhausts causing the difference to increase. Perhapes this sittuation may be a majer reason why we tend to blow our motors with only miner modifications. I would really like to see some dyno results to prove this theary (HP & EGT). A couple of reasons the front might be longer are because of the air pump and water neck placement.

 

You can tell the PowerFC that the injectors are different sizes. I suppose you could just say that one of the secondaries is smaller than the other to get it to dump more fuel. However, it wouldn't surprise me if the PowerFC just used one of the settings and ignored the other. It seems like this should work to deliver more fuel, but who knows if they really programmed it to use both settings.

So it sounds like everyone is convinced that the rear secondary flows better than the front secondary for various reasons. I guess I find that somewhat surprising after looking at the pinch in the runner. Though perhaps it isn't as bad as I remember. I'm really interested to hear from someone (Ralph? Rob?) that knows the scoop. Or maybe I should just get myself an RXTuner and read that.

-Max

 

Max maybe these pictures will show the size of the runner better....if you look at the middle 2 runners you can see 2 small holes where the egr used to be.

http://plaza.ufl.edu/yanni25/7work/LIM%20WPH/2.jpg
http://plaza.ufl.edu/yanni25/7work/LIM%20WPH/6.jpg

 

You can do it with the PFC; for the rear secondary injector size, make it smaller than it really is.

When I got my calibrated 1200s from RC, I placed the larger one in the rear, and set the injector size as the average of the two. Thus the front runs leaner than the rear.

You can change this bias as much as you want.

 

As Max said, Rob from Pineapple touched on the flow mismatch during the tech session at Seven Stock. Apparently, Pineapple motors are built around this and if you disassemble one, you'll see that the porting for the rear rotor is different.

Sonny