LokiRx7.1

iTrader: (1)

What luck have any of you had with different carbs? I've used a mikuni sidedraft for years now and it is very reliable although finicky at times, and seems to have been a great power adder. It also makes a great noise when I rev it or get on it really hard.

Just wondering what carb seems to be netting the most power reliably, I love the Mikuni but I want more power. I dont really know the advantages/disadvantages if any between sidedraft and downdraft. Although in changing my carbs from down to side, I noticed a huge improvment in low end torque, I'm assuming this is mainly caused by the longer wrap around intake, which almost seems as an early cold air intake, by seperating the intake and exhaust. But anyway please let me know what you guys have.

FB II

you have a great carb... switching up will probably not net you much more power if any. it's time to look at other options for more ponies

Midwest 7's

iTrader: (4)

have you street ported your motor yet?

LokiRx7.1

iTrader: (1)

Well I'm J/W..... I have about everything I can order from RB and I still dont get the power I want, its making close to 250 HP at the flywheel N/A and theres just nothing else I can see to do. I've looked into Camden Superchargers and Assorted Turbochargers and I dont want to boost a 12A, I love it cause its got alot of *** to it.
However this summer I will be buying a beatup TII (Bank wants to give me a loan ) so I'm sure I'll have all sorts of fun with that, but I dont think I will swap motors, really whats the point of swapping a TII into an FB, Its cool as ******* hell, but from a performance perspective. How much will I gain because I think FC's only weigh marginally more. but anyway, what I'm saying is I love the little 12A and I dont see it going anywhere....

LokiRx7.1

iTrader: (1)

Motor is ported, I did have it J-ported but the idle was sickening, so I bought another 12A and did a mild street port and switched all my hardware between the motors. So I have a J-ported 12A with port matching just sitting in the garage. Realistically I didnt notice a huge difference other than the fact I had a smoother Idle and more low end power, which was what I need most. The J-port is more extreme and to close to a P-port for streetabilty.

However I am considering Nitrous Oxide maybe in 150-200 shots or maybe a little less, but I dont know what kind of Fab it will take to put a fogger system on a 12A

bean_8044

does your manifold have any ports on it? i have a mikuni side draft mani and it has a port for every runner

LokiRx7.1

iTrader: (1)

Yeah that sounds exactly like mine
Sorry crappy angle but you should get the idea

FB II

how do you know you're making 250 flywheel hp? i think you should get on a dyno

but if you don't want to go turbo... then nitrous is your answer. nitrous is fuggin awesome when setup properly and can be just as relaible as any mod.

also, i have a take on why a turbo fb is better than a turbo fc..... it takes around 370rwhp +/- to get in to the 11's in a TII. it takes 300rwhp +/- to do the same in an FB. sooo, put that 370rwhp in to the FB and what do you think it will run? you can break in to the 12's with just shy over 200rwhp in a 1st gen; are you running 12's?

DriveFast7

iTrader: (1)

Put bigger chokes in the carb.

LokiRx7.1

iTrader: (1)

Okay heres the scoop, until 1993 other than the exhaust my car was totally stock. I got a large tax return and before that I had received a large Christmas bonus (I saved my bonus because I knew I was getting a decent return) I spent the next six months saving money and tearing my engine down. After pulling it and tearing it down, I bought pretty much every 81 specific 12A part Racing Beat has, I mean I could list but it would be alot easier just to say that, I was planning on a Dellorto carb/manifold setup, but a friend of mine who rebuilds alot of air cooled VW engines told me about a 12A sand rail that had been in an accident and the owner was trying to get rid of it. It had a Mikuni Carb/intake. I called RB and the guy I talked to said Mikuni was possibly one of the best setups out there. He basically told me to hurry up and buy it. so I did, it was only slightly used so I rebuilt it and rejetted it. However in all of this I made a big mistake, I still have the factory Ignition Coils and FB distributor. Although I did buy RB plug wires.... After having the assembly balanced I called RB and asked how much power I should make with this setup, they had no clue they said if the engines already out of the car just take it to a dyno. so I did in 1997 I took it to a dyno and had it done. I had around 24something.something so basically 240 HP (I know I rounded ) on an engine with 80,000 miles. however after the rebuild it was basically a new motor, it has 140,000 on the odo now, and thats mostly hard driving. (save for the break in period) so Id say closer to 230 HP currently.

And no I have no idea what it would do in a 1/4 mile. never taken it there although my father swears it will break 12's I am still skeptical whether it will make 12's. I take it to mid-ohio at least once a year. and it powers out of the corners like no other.

Kilkare raceway is the closet 1/4 strip, I have no idea how to get there from here. I just got new tires so here pretty soon would actually be an ideal time to go. You have me thinking now damnit....

I used to have a Camaro IROC-Z with close to 450 HP at the wheels, it would run 12's and 13's consistantly, I guess the Rx-7s lauch is comparable to that. off the line its very violent.
My Camaro had a GM Performance Crate engine with aluminum heads, wicked cam, holley double pumper 650 CFM Hi-Comperssion pistons forged connecting rods, steel crank etc. etc. I know there was alot more done to it, I know we did some weight reduction to it as well, and traction bars were a must.

So I honestly dont know, I have really run out of options.... Im old getting fat and Im bored, I need something to do. I want to go faster, If I were to swap a TII I would do it the same way, at least save some money, and in the meantime strip the engine and pull it, and build it from the ground up. Thats what I did to the 350 in the Camaro, with stronger internals already in place you dont have to waste time tearing your engine apart again to rebuild it, when you should have done it to begin with. so I would make an astronomical unreachable goal, and then I would build towards it. but being as Im old fat and lazy, I dont know if I want to start another project. especially a turbo, cause theres a learning curve that I'll need and it will take a lot of time. so anyway Im rambling, so later
Loki

LokiRx7.1

iTrader: (1)

Nitrous sounds like the way to go, although I am intrigued by the turbo. I love learning new things, I just dont know if I have the time anymore....

FB II

just curious, what was the porting on the engine that did 240fwhp?

either way, 200Rwhp will net you very close to 12's... with a turbo setup you could break 12.9 with same said power due to the addition of much needed torque.

it really all depends. do you want a faster, more fun street machine??? TURBO

or do you want what you have now, but be able to goose it against someone on the highway... so long as your bottle is filled NITROUS

my vote will always be BOOOOOOOOST ahahaha

LokiRx7.1

iTrader: (1)

Right now I think its just a mild street port, but that depends on your definition of mild, I think its basically a full street port. I had the engine Dyno'd with the setup I have now, in '99 I Bridge-Ported it and in '00 went for a J-Port. The larger port sizes dont net you a whole lot of gain, well you do get a gain but the more its ported the higher your powerband goes. With a J-port I was idleing around 1500K that quickly became annoying... so I recently got a junk 12A took the block and essentially swapped all the hardware. after of course I ported it. I liked the power gain but I didnt have the power where I wanted it. I could kill ricers at a roll, but from a launch I had no torque. so smaller ports and on went a weighted flywheel. It may or may not have the same amount of power, I cant tell you. from road feel I have to say its every bit as potent as it was when it was dyno'd. but its been years since then and I may not even exactly remember the feel power fall off would have been so gradual I may not have noticed it.... if there was any at all.

What I'm saying is, your driving me nuts! I am getting a new exhaust here soon and now all I want to do is find a car dyno to see what I'm putting to the pavement. Your spending money I dont have!!! (LOL!) But I do want to take it to the 1/4 mile, I just havent gave it alot of thought recently......

LokiRx7.1

iTrader: (1)

I also got a carb spacer to improve low end torque all in all I think Im mostly afraid of a turbo killing my launch. I have alot of torque now, when it was dyno'd it had 210 ft/lbs. which wasnt enough for me. And take into consideration the carb wasnt jetted or dialed in like it is now. larger port sizes can kill your torque as well as a lightweight flywheel, if you dont have alot of torque to begin with, these mods further your problem. smaller ports and a wrap around intake cause the "dynamic supercharging effect" which 13B manifolds take advantage of. All it is, is the long intake runners allow a larger intake charge, however as the rotor opens and closes the port, your intake charge will "bounce" and attempt to exit the carb. (i.e. carb backfire) so the side draft carb much like the sidedraft throttle body just continues to suck in air and forces the "bounce" not to occur as there is just to much air being jammed in, so the intake is slightly pressurized, this can only happen with a long intake with seperate runners for each port. other wise the pressure waves would randomly bounce around. in a wrap around intake, well it can only go up or down. cool little things you learn along the way. A larger port is open longer and the pressure wave doesnt have time to build up, so realiticly a larger port doesnt make much of a difference. unless your using a downdraft setup. I may be wrong I havent explained this in years so let me know....

LokiRx7.1

iTrader: (1)

Going to sleep, will post in the morning... later all..

FB II

aahahah, i'm sorry bro. i'm not trying to get you all lit up. i must say this... if you are looking for torque then you need a turbo it's pretty much the only way to get gobs of it on a rotary. look at a stock TII's hp numbers. s5's are 200hp and 190tq!!!!! that's stock! you can't get that in n/a form. coming off the line is better than ever, granted you can keep the tires from spinning hahaha

LokiRx7.1

iTrader: (1)

Lol!! Im not getting lit up, Im mad at my wallet because I cant keep cobwebs out of it anymore lol!! I always thought down low a turbo killed low end power, because it doesnt spool until like 2-3K, or does it spool just by revving? for some reason I thought you needed engine load to build boost..... Because I lauch around 4-5K anyway.... but I will try to find a "test and tune" night at kilkare and get directions, I'll let you know how it goes. I'll have my wife pay for track time if I have to, I'll just have to take her for a few rides on the track. (I pay for all of her stuff, so she owes me at least that much... Which is why im BROKE!!! oh well, i still love her.......................) but I dont know, like I said I love learning, and I dont know much about turbos......

FB II

it's all about properly sizing a turbo... hell for track use it doesn't really matter. like you said, you launch around 5k or so which leaving the line with that kind of load will not hurt your low end

with a ported motor, especially big exhaust porting, spool up isn't really an issue. just get a nice T 60-1 and 350 - 400rwhp is no problem w/ proper tuning. you will start building boost the second you floor it and should make 10psi around 2700 and 15psi before 3500 or so. this is rough, but a good general estimate.

turbo's and rotaries are like stink and ****.... they just go together

LokiRx7.1

iTrader: (1)

lol!, well I might just look into this then...... what about using Nitrous to cool the intake? wow so many options.... do they make a way to keep your bov quiet? that would make a great sleeper..... and if you wouldnt mind do you have some pics of your setup? J/W...

FB II

give me your email and i'll send some pics of the setup.

you can always recirculate your bov to keep the noise down and it still functions the same. as far as nitrous for cooling... that would work very well, but it all depends. spraying on the intercooler is one way, but a bit un neccessary. your best bet to keep temps down is meth/water injection. that's a whole different discussion

LokiRx7.1

iTrader: (1)

alright, rfox0720@sbcglobal.net alright I'm not going to turn this thread into a turbo discussion. I can usually get by on my own pretty well. but thx for the info

trochoid

iTrader: (6)

Loki,

I'm running a 1/2sp-1/2bp with the wrap around Mikuni and would like to ask you about your jetting and exhaust. I think these 2 items are holding back a good deal of my power. It just doesn't seem like it has the power it should for the porting.

I have the old Rotary Performance header and silencer, going to a 2"+ gutted glass pack and a Dynomax muffler. The over axle piece is still stock, and I think that is a choke point for the exhaust. As far as jetting, I will have to dig out my list. I went to a bigger air jet since it was running so rich, still is a bit. I also need to upgrade the ignition, still running stock atm.

Any advice would be greatly appreciated. At this point, I have all the parts for doing the TII swap and I am seriously concidering it for more power. Off the line the bp is a dog, still haven't hit 8k rpm yet, finally have 2k on the rebuild, so it's time to try it out.

LokiRx7.1

iTrader: (1)

I'll have to find all the paper related ****, as I dont remember what jetting I have. Last time I fucked with that was well over a year ago. I think there basically the most massive jetting I could find for the carb. I run so rich that if I run the car in the garage it burns my eyes. I have it dialed in for best performance, and it always runs stronger when the mixture is rich. I have just a RB exhaust, A rotary engineering header, and a rotary engineering muffler. To bad rotary engineering is out of business, good people. I have no cats just running a straight pipe to the muffler. In a few weeks I will have a 2.25 inch into a magnaflow and a split after the magnaflow (SD) so I can run two ebay cannons side by side, the spit will be 2 inch pipe. if I have to I'll get the perforated pipe before the Magnaflow to eliminate noise.

at one point I took my jets and overbored them on a drill press, killer solution, as long as you dont get "bit chatter" as it WILL instantly ruin your jets. I love the Mikuni great carb. play around with it, I can help but only so much. I also have a custom ureathane 1.5 inch spacer after the carb, a machine shop can make it. Also K&N air filter, I think it outflows about anything out there. sorry so vague, give me some time to dig up the info
Loki

trochoid

iTrader: (6)

Great, and thanks. I don't have a filter on the carb, and I know I need to have a new over axle piece made. I will look forward to your posting. Btw, do you have any idea what your afr's are running? I have a wideband available for tuning.

FB II

if you have a wideband shoot for around high 12's under WOT.