mrhalfwitt

This will be my first PP setup and I have been reading all I can. I think I have it all figured out but I want some one from the outside to pick my brain.

My understanding is that the lower I keep my maximum rpm the longer the engine will last, and the only action my car sees is daily driving, the occasional auto cross and some drift action in my local industrial park. So I'm not going for maximum HP. I'd rather be happy with strong numbers and be confident in a setup that will last for years to come.

I'm still collecting parts and i'm months away from the actual build but I don't want to buy anything that I cant use because I don't know what i'm doing.

Parts I have so far....
89 non turbo fc
two PP 13b housings made by speed source
Complete S5 N/A engine
2X 1000 RC injectors
Megasquirt 2 with V3 board

Parts I have been looking at.

First of all I was thinking about going with the racing beat intake manifold with the Weber base plate and going with these throttle bodies

http://www.cbperformance.com/catalog.asp?ProductID=412

But my question is.... The Racing Beat Weber carbs they have are 51mm, butt...

I want to set my rev limiter for 7500 rpm for longevity, and from what i'm reading I may not even need the 51mm. And I want to stay with EFI for tuning purposes.

As for fuel, the bosch 044 and a regulator of some sort.

As for the exhaust i was thinking about going with the Racing Beat road race exhaust system, but wasn't sure if it was ok to use.

Please let me know how you would do it. Thank you!

nvmarx

iTrader: (1)

http://www.ebay.com/sch/i.html?_odkw...+body&_sacat=0

this is what i have
check my build thread for pics
you have obviously done your research i like that, your on track bro good job

mrhalfwitt

Wow, do they work well? And I see your using a surge tank, how do they work... I mean What do they do? I know allot of the drifter guys use them but i don't know what there for? This is some of the info I could find... http://www.ratdat.com/?p=168

Kenku

48mm throttle bodies will work; the 51IDA may be 51mm at the throttle plates, but if you look up Racing Beat's jetting reccomendation, they're putting a 46mm venturi in it, which is probably more of a restriction than a 48mm butterfly with no venturi. You can go even bigger on throttle bodies (EFI not caring about velocity through the things to meter fuel) but for what you're looking at, 48mm should be at the very least an OK starting point.

Peripheral ports may theoretically want a different exhaust runner length than the RB system will be designed for; they have a page on their tech pages takling about typical exhaust configurations. On the other hand, if you're not really up to doing that custom, well, especially with your lower desired redline, maybe the RB system wouldn't be that bad. Not ideal, but 'ideal' takes a lot of fiddling to get to on NA rotaries. Some of this also depends on how the speedsource housings are ported.

More questions, I know.

peejay

Don't use a rev limiter, it hurts more than it helps.

Keep the revs under 9400-ish and you should be fine. That has been the general max RPM that I would use on my 2mm seal engines and I never had any RPM-related failures. I'd zing 'em momentarily into 5 figure range on a couple occasions (momentary on a mis-shift, not under load) and everything held together.

nvmarx

iTrader: (1)

i dont know i havent got it running yet waiting till paint is done.
surge tank is just there so there is all ways fuel for the main pump/pumps.
there is other ways of getting the same results like sumping the fuel tank and having the fuel being sucked from the bottom.

how mine works is the small low pressure carter fuel pump sucks the fuel out of the main tank and fills the surge tank then the main walbro pumps strait to the fuel rail then out the the regulator then back into the main fuel tank

i chose the actic cat throttle body because it was so cheap and it came with fuel rail tps injectors its 50mm and they have semi built in trumpets

mrhalfwitt

Speed Source is regulated to 7500 rpm by the GT series for a few reasons. These ports to me look odd but keep in mind they also use them in a 20b configuration. So I will not have any clue how they will behave in a 13b configuration.

Kenku

Huh, that's interesting. Looks like the way they're ovalling the port there's going to be more duration than the standard holes people do. Wonder what effect that'll have.

Last I checked Grand Am rules, Speedsource is limited to only 52mm throttle bodies too; the 50mm Artic Cat ones wouldn't be much more of a restriction.

j9fd3s

iTrader: (3)

put a degree wheel on it. if you're cheap like me you can google it and print one out.

my 12A pp has huge ports too, and its surprisingly docile, makes plenty of power under 7k, in fact with the stock air cleaner on it, the power peak is about 5500-6000rpm.

skip the rev limiter, its safer to over rev it, than it is to have the stop/start of the limiter. actually with EFI it might be more effective to have the mixture go really rich over 7500, or retard the timing a little, so its not a limiter, but a power reducer.

or hell just put a 12A air cleaner on it, and don't worry about it

RotaryEvolution

iTrader: (30)

to elaborate on your ideas of wear and rotaries you need to keep in mind wear is relevant to high RPMs, not just higher than average. most excessive wear comes from 7k and beyond sustained for long periods of time and is compounded by the seals you use. ie 3mm heavy metallic apex seals will chatter and peel chrome, 2mm will to a lesser extent and carbon/ceramics will cause the least amount of wear to the housing/rotor.

balance of the rotor tips will also play when in that range where the rotor may begin to wobble and cause more bearing wear(to the point that the rotor tips may gouge into the irons) and side seal to iron wear causing steps to develop, this is where rotor lightening and rebalancing would help as well as a nice trued lapped/cut surface versus reusing used irons with excessive wear. a worn rotor housing may also push a perfectly balanced rotor out due to runout as the seal pushes forces in different directions on the rotor at various points.

premixing more heavily will also prevent a chunk of wear versus relying on the oil metering pump which is really more suited to daily driving habits versus actual racing habits.


most people don't really think about blueprinting a rotary and it really is only necessary if you want one to last when pushing 9k+ RPMs for longer periods of time. as well, most builders would just toss an engine together with new parts as that is fairly close to already blueprinting one of these engines versus trying to attempt to get used parts that are within decent tolerances for high RPM use.

mrhalfwitt

One thing I wanted to touch on with the Megasquirt and it's rev limiter is all of the options, typically i use both soft and hard cuts. Lets say my soft cut would be at 8000 rpm with only ignition cut every other cycle and a hard cut at 9000 rpm cutting spark every cycle. I have done allot of tuning with turbo 13b and the megasquirt and always stuck to the rule that I never use a fuel cut... ever...

And secondly does anyone know where I can get these irons cut and re-nitrated? They have minimal step wear and can barely feel it but i'd feel safer with a fresh start.

j9fd3s

iTrader: (3)

its not a super huge deal, but it seems to be worse to hit the rev limiter @high revs than it is to just let it go. the stop/start is bad.

it doesn't have anything to do with fuel cut, its more like the loading/unloading on the stat gear teeth.

its not a big deal to hit it here and there @8k, but if you plan to go to 9k, i would turn the limiter off, and just make the map so that you loose power

mrhalfwitt

I'll keep that in mind.

speedturn

iTrader: (1)

If you shift a PP at 7500 rpm, and if you have a typical stock wide ratio transmission, then you will fall out of the power band every time you shift gears. I tried that years ago, and was very unhappy with it. When a PP motor falls out of the powerband, it feels like a slug until it comes back in the power band again. You can calculate what rpm you will drop to with each gear change based on your transmission ratios, or you can just drive your car or a friends car and observe what the rpms drop to. On a stock Mazda transmission the rpm drop is much more severe in the lower gears, especially the 1-2 shift. That is why special close ratio racing transmissions were made for peripheral ported race engines.

I have been racing PP motors since 1997 now. My current PP race motor has been in my road racer since 2004 without needing a rebuild. I keep the shift point to 8800 rpm. It has occasionally zinged higher from missed shifts, but I try and shift it at 8800 and it lasts and lasts. It does not get below 7000 rpm during a race; I run a really close ratio racing transmission so that it will never fall out of the torque band.

mrhalfwitt

That is a point of view I haven't even thought about yet. I guess I gave more reaserch to do after all.

mrhalfwitt

Well it looks like i'm getting a shell to put this in and dedicate it to drifting. Pix as soon as the project gets serious...