no one walked on it lol. this guy was getting busy with his lady on the roof

 

OK, I have returned from the dyno. All the results are not corrected to sea level, they are the number produced at the wheels at my elevation of 5000 feet (Reno NV). First pull is a motor only pull, 20 degrees of timing on my locked out distributer, NGK 10.5 plugs, 114 octane VP race gas premixed with two stroke oil. 600DP holley carb on a racing beat manifold, sitting on a 1/2 spacer plate, and the manifold was port 1/2 down to create a "plenum". Holley carb had 58's in the front, 64's in the back. The header uses 2.25 inch primaries that are 20 inches long, and merge into a 3 inch collector, and the 3 inch muffler is located some 30 inches after that, dumping out right after the muffler (right behind the back of the door, before axle). 157 HP at 8800 rpm. A/F on the dyno said I was at 13.5 in the top of the pull, so we up the rear jets of the carb to 68's and decided to make a nitrous pull. The two foggers had 36's on the fuel AND nitrous, which is supposed to add up to ONE 47 jet, which is what NOS says is equal to a 100 shot. The bottle was at 900 PSI, and the fuel pressure on the nitrous side was 4psi. All other aspects of the tuneup remained unchanged from the motor pull. When the nitrous activated, the fuel pressure dropped to 3psi but remained steady. A "mist" appeared right above the carb, it looked as if atomized fuel was coming back up through the carb. I could now also hear the "rasp" I've been describing. I could hear it in the motor, and also it appeared to make the sound out the carb as well. If I would describe it, I would say it sounded like someone clicking two marbles together, but very fast, and it grew more rapid as the engine accelerated. We made a full pull, and the car made 223 horsepower at 8400rpm. 70 (or so) more horse. Stumped, the bottle pressure was fine, and the fuel pressure for both nitrous and carb remained steady during the pull. A buddy suggests PULLING timing to see what happens. I back the timing down to 15 degrees (make a drastic change to see a bigger result). We make another pull, leaving all other aspects of the tuneup the same. The car makes 243 horsepower at 8400rpm. 20 more horsepower with LESS timing. PLUS, the marble clicking/rasp is GONE. Is the "rasp" what a rotary sounds like when it is detonating? At this stage, I am inclined to think so. We pulled 5 MORE degrees (for a total timing of 10 degrees) to see what would happen. The car made 242 horsepower. It lost ONE horsepower. Weird, but the rasp is still gone, and the engine seems to make smooth power. Well, by now we think we have a handle on the tuneup for the 100 shot, so now we change the jets to 55's on fuel AND nitrous. This should be roughly equal to a 180 shot. The bottle pressure is now at 800psi. We decide not to swap bottles as a SAFETY margin on the first pull at more power. The tuneup remains the same, 10 degrees, same fuel pressures. The car is loaded and we stab the button, and she hits for maybe one second, then backfires through the carb, shooting a 3 foot flame into the air. Impressive sight, but no she wont idle, and a compression check reveals she is DEAD. I'm bummed. The part that gets me down is, Im not even sure this motor will take a 180 shot. Im even more bummed that I dont know WHY. With 240 horse it might run 12.0 to 11.9 at its current weight of 2150 with me in it. I would need to survive the 180 shot to be in the low 11's, which is more where I want to be with this car. I'm very bummed, to say the least. Thats what happened, I wanted to let everyone know, so future nitrous/rotary newbies can be one step ahead of the game. Now you know what I know.

 

that marble clicking u described, yes, that's what a spark knock sounds like. timing should have been retarded before spraying. it's possible u cracked an apex seal letting it continue to knock during the pull rather than back off the throttle as soon as u heard it. sorry to hear it let go tho.

 

player I feel for you but you were running to low of jet in the primaries the jet exchange between the front and the back as recommended by holly has to be at least two jet sizez minimum. But keep your spirits high rebuild the motor and start over again. When you retard to much your run into a problem of blowing the motor. Wish you the best man and don't sell that car playa. Que se le baye bein hermano!!!

 

no worries guys i wont let him sell that car. too much blood sweat and tears into it. as for the motor......... thas another story altogether

 

sheesh. You guys kill me.

 

Much better...

PS. sorry to hear about the motor issues...

 

Doc,

I have a bunch of 12A cores used parts if you need any parts to put your motor back together let me know. I'll give them to you for free just pay for the shipping charges for whatever you need.

Recommendations:
- If your interested in changing your fuel system to a high pressure system let me know. I can get the high pressure/high volume pumps for about $200.00. But, you'll have to upgrade your regulators which I can help with also.
- Go to a colder plug NGK 11.5 or 13.0 Heat Range. (This will suppress detonation)
- Use a higher Octane fuel VP C16 works really well. (This will suppress detonation also)
- Have 2 different tune-ups on the carb one for Nitrous use, and another for off track usage.


When you mentioned raspy noise I should have asked for more details. I never heard detonation described using that word.

Like I said earlier if you need the parts just let me know what you need. I am glad to see you wrote everything down because most people don't. Keep your notes handy this will save you from losing another motor next time.

Keep your head up we are here to support you in your efforts.
Thanks
Albert

 

What made it backfire through the carb? Should it be able to handle a 180shot? I'm thinking it would have made near 330 horse that way? Is that too big a hit for a 12a? What was wrong with the tuneup? I've never heard of a 13.0 heat range. Please provide a link or part #. Are they 30 bux each like the 11.5's?
The only tuneup I was trying to acheive was a track tuneup. I have been suggested to run 20 degrees on a 100 shot by numerous people, thats why I started there. I also mentioned thats what I used on a 100 shot previously in this thread, and no one said this was a bad idea (Rxtsay3).
The "rasp" I describe was always heard out the exhaust, or so I thought. But on the dyno I could hear it in the carb.
I'm gonna tear down the motor to see what went away, I may hit you up for those parts. Thanks for the offer.

 

I can get the 11.5 for much less than $30.00 dollars each plug.

 

Sorry forgot to right this information in the last reply. Yes I can get them, and they are cheaper than the 11.5. I'll have to call about the pricing it has been a while since I purchased them.

Albert

 

Sorry to hear about your engine. I know it's alot more expensive, but why don't you go with a turbo set up on your next engine and toss the nitrous set up. Much more reliable and less wear and tear on the engine. Good luck, hope you get back on the track soon.

 

Some higher force is telling me to not mess with these anymore. I got the motor out, but for some strange reason (and a first for me), the damn flywheel will NOT come off. I have released so much hate through my rubber mallet into that damn flywheel, yet it wont pop. I even put a puller on it (haha) and she is stuck. I just wanted you all to kow the pain I am going through. PS, I looked at the apex seals through the exhaust port, they all are fine, so if the broke, it is on the side that is covered by the housing, cuz I dont see any damage yet. No springyness though, haha. I flattened those poor springs!

 

Okay lets cut to the chase are you going to rebuild and start over again man give us some info man what it do

 

If it is just springs or side seals that is not a big deal. At least you don't have to go port a whole entire engine. Now that is a real pain in the butt.

Look at http://www.hurley-engineering.ltd.uk/ they have some aftermarket side seals that are suppose to be pretty good. I have never tried them in my engine yet, but I ordered a set for my all motor setup.

Good Luck
Albert

 

I was running Atkins apex seals with solid corners and 93 corner springs. Double springs on the side seals. If I somehow damaged a side seal, I will be impressed. I'm gonna keep trying to get the evil flywheel off. I'll take lots of pics.

 

if you cant get it off let me know i have a 3/4 inch air gun and a 2 1/4 socket

 

I have the nut off, i have air tools and all the junk, I cant get the flywheel to RELEASE from the damn crank. She is stuck. I'm taking the passive aggressive approach now, Im gonna ignore her, and maybe she will give up. lol

 

ill come and get it off you limp wristed ***

 

Take the front assembly apart and then wedge something between the flywheel and the rear plate. I usally use a large chisel and then smack the flywheel with a large rubber mallet. It will pop right off. Sorry to hear about you troubles. Good luck with you.

 

I got the flywheel off and opened her up. No apex seals are broken. All the springs are flat though, and the corner seals are pushed into the corner slots so they sit flush. The apex seals look "blue" like stainless steel when it gets welded. Haha. I guess they got hot. The rotor housings have little score lines in them that you can see and feel with your fingernail, the side plates even have little scores you can feel with your finger nail. AWESOME. I would think this heat would be from lack of lubrication, but I know for a FACT that I have mixed all my gas with premix. 8oz for every 5 gallons. When I opened the motor up, there weas no oil inside the housings (on the face of the chrome). Normally, when I open them up, they have a film of oil on them. Who knows. The rotors are screwed, the housing are screwed, tha plates are screwed. Rotarys are so cool.

 

Sorry to hear of you missfortune. Hope you get back up and running soon.

 

*sigh* im really sorry to hear that josh. i really am no ****. you know where you need to go from here so take some time then make the big leap and never look back. i love you man

 

Anybody want to buy any of my stuff? I have 2 MSD 6AL's. 2 MSD digital 4 stage retard boxes, 2 MSD blaster coils. 2 MSD two step boxes, 2 distributors, 12abp side plates that will need to be resurfaced, a lightened flywheel (maybe MFR?), a 79 tranny, a header that fits a 12a into a RX3, a driveshaft for a 12a with 79 trans to a 9 inch in RX3, a Racing Beat 12a intake manifold with throttle cable bracket, a KGParts 13bREW holley intake manifold, a Holley 600 Double pumper carb, 2 holley blue pumps with reguators, a haltech F9 ECU with harness, a Stainless turbo header for a 13b (supposedly for an RX2). Lightened 12a E-shaft. NOS big shot plate (just the plate). I guess thats about it. Let me know.

 

keep that driveshaft. you can change the front yoke and itll save you money.