BadAssRX-7

well went to the drags with a friend same set up other than motors and carb.... i have a street ported 12a with stock intake(k&n) with 9k on it. a friend had 119k on stock ported motor and a webber 54mm. he had 3 sec. on me in the 1/4 THAT SUCKS


venting over

peejay

Ouch! What were the times like? (60', 1/8, 1/4) When were you shifting?

piston pounder

yeah, stock carbs suck, but my 54mm kicked your ***!-

jimmyv13

You should be a hell of a lot closer than that. 3 seconds......WOW.
Is there something he's not telling you? That's like a 16 to a 13. It doesn't seem possible that he can be 3 sec in front of you with a stock motor and a weber, even if he does have other mods. Is your carb tuned right? What are your timing marks at, L and T? You could try DLIDFIS if you haven't already. Let us know how he's so fast.

BadAssRX-7

ok heres the info
denver colorado...bandimere speedway 5800 feet
my 83 l.e. best did.
r/t .575 (pretty dam good)
60' 2.678
330 7.632
1/8th 11.788
mph 59.14
1000 15.399
1/4 18.455
mph 73.80

this is with stock timing and stock carb, header to highflow cat. no top or air filter @2710 lbs
**** my old stock motor with 206k did a 17.99 @ 600 feet with just a race exh. and what the hell is that dlidfis thing? any ideas people

jimmyv13

Jeff20B's ignition set-up. I haven't tried it yet, but I've heard nothing but raves about it. Click DLIDFIS for details.

There has got to be something wrong with your car. Your r/t is good, but did you spin the tires? Your 60' time could be better, and you accelerated from 59 MPH to 74 MPH in the second 1/8th????

I believe something is wrong somewhere with your car. You should be in the 16's at least.

Jeff20B

iTrader: (13)

Just a note about Yaw's timing settings mentioned in my article. They are good for low RPM, but aren't very good for high RPM. You might break Trailing plugs. It might be a good idea to go to 20*BTDC instead of 24* or 25*. I still like the 10* or 8* split.

peejay

Wow... I know Denver has some shitty air but you should not be running mid 18's! You should be able to get your 60' down quite a bit. That won't bring you into the low 16's though... what RPM are you shifting at? Still running the stock fuel pump?

Also you NEED to run an air filter! It straightens the air going into the carb and rotaries do NOT like dirt. It gets stuck in between the rotor and the sde housing in the area between the side seals and the oil seals and it grinds away at your side housings and pretty soon your engine is an oil-burning low-compression pig. It doesn't just blow through the engine like in a boinger.

Felix Wankel

Did you miss a gear? It took you over THREE SECONDS to go 320 feet! Your car must be leaning out like hell on the big end.

Turbo FB.

Posibly a week clutch, presure plate, cloged kat, pitted cap & rotor, fouled plugs, sticky brake caliper, on and on. Check this plus all the stuff everyone else said.

BadAssRX-7

ok well the wheels were spinning 4 sure had some good rubber on the *** og my car after the races. Ok i have a a/f guage and it acc shows me a little rich. I only ran the 3 runs with out a filter. I still have the stock fuel pump, and was shifting at 7k-7500. She has msd coils(new), new cap and button, ultra red wires that seem good, and plugs with 1200 miles on them. on the street she seems ok but not to good on the track. I did knowtis a BIG diffrence when i went from Denver to iowa, she LOVED the lower air, i was barking 3rd all over the place. it almost seems that the 4bbrl isnt opening, i dont get that 4kish KICK from the 4bbrl.
there were 2 other 7's there. a gsl-se running mid 17's and a 79 running high 19's both were stock. My clutch has 9-10k on it, and grabs like a BITCH.... no sliping, it acc almost killed the car on my 1st run, i didnt have the right foot on the floor and she about choked.
I'm at a loss.

speckamp

FUEL! How old is the fuel filter? I've heard that they go real quick. I'd check yer secondaries if you don't think they're opening... maybe you have a vac leak and they aren't getting enough vac to open? I don't see any real reason he should be running that much faster than you!

--matt

Felix Wankel

Man I think your A/F gauge is lying to you. My car ran lean with the stocker, and I have a stock ported motor versus your big daddy street port.

BadAssRX-7

ok i did all the "right stuff" when i got the car(in june) the day before 7 stock . after i got her home i put in a K&N in the stock box, replaced the plugs and stuff then swaped motors so it doesnt mater. replaces the fuel filter,added redline to the tranny and diff.. see im at a BIG loss in atl. i was putting 165 to the ground but the smog ****'s in Denver wouldnt like the dellorto so i went back to stock intake. I do plan to do a yaw carb and flowed intake 1 day but not right now(may be sooner than i want)
I guess its time to fire up the car and get the starting fluid to find out if i have a leak.

peejay

OK... I have a stock carb and an open header on my (slightly) ported 12A and I get my best times shiting at 7200-7500. With an exhaust on it I get my best times shifting at 6800! The stock carb really hurts the upper end! You NEED zero exhaust restriction to make any sort of high-end power, and even then the car will make more noise than power towards the top end.

Felix is right... I don't care what your O2 meter says... you need more fuel. Period. The stock fuel pump is ALMOST good enough to reliably supply enough fuel for the stock 102hp... you're trying to make 50% more than that so you need at LEAST 50% more fuel, and the stock pump is sitting there laughing at you 'cos there's no way it'll supply it.

- PJ (15.475 open header (2.3 60'), 15.8 thru muffler (2.2 60')... STOCK carb... STOCK air cleaner... so it CAN be done!)

speckamp

Paul Yaw reccomends an aftermarket fuel pump and external regulator... I'm guessing this is for the reason peejay mentioned, the stock one just can't keep up. I'm guessing this should probably be the next line of upgrades for ya.

--matt
(wanting a nice external, high flow fuel pump for his -SE which is craving boost)

piston pounder

Ok heres my setup(Badass is talking about my 7)
-Weber 45mm sidedraft carb and intake from MazdaTrix
-Mindtrain stage5 header and stage 5 exhaust without cat.
-Electric cooling fan
-Stock fuel pump(does supply enough fuel for you guys that think it cant handle more H.P.)
-Timing set at 5 leading 25 trailing(no vaccum advance hooked up)
-Custom short shifter
83 12a stock motor converted to oil cooler under radiator, heater core and radiator outlets blocked off.
-84 drumbrake rear end(no posi) yet!
-1981 gsl slightly guted interior
This was my first time at the stripand ran a best time of 16.4 and best mph was 84. launching at 4000rpm. Dave it has to be the stock carb! not the fuel pump, not any vaccum leaks.Come on I put your motor in remember!.

peejay

What does "Stage 5" mean?



I found differently. I was stuck in the mid 16's with the stock pump, upgraded it and I dropped to the high 15's. Then I eliminated the return line and the regulator (internal reg. pump) and I dropped to mid 15's with no traction - probably have another tenth or two left in the car.



Huh??? You have trailing set 20 degrees advanced of the leading?

It's the fuel pump... I'm going way faster than that with less port and a restrictive exhaust (on the 15.8 runs). Oh yeah, and my car isn't gutted, heck it still has A/C installed.

Felix Wankel

Wrong.

rx7passion

the only way the stock pump is going to be suficent enough is if it is brand new right out of the box. if you put a carter or whatever external FP you want it will help alot! it did with my car 10x when i had my yaw carb on and no fuel pump upgrade over 6k at more than 3/4 throttle it would bog down horribley

piston pounder

-stage 5 is all street legal, everything will bolt to stock exhaust pieces.
-yes leading set at 5 degrees(stock is 0 degrees right?) Trailing set at 25 degrees(stock is 20 degrees right?) I was told to set them at these settings since i have no advance.
my stock fuel pump has not had a problem supplying my weber(no bogging or hesitation) I do not have a return line hooked up.

peejay

-yes leading set at 5 degrees(stock is 0 degrees right?) Trailing set at 25 degrees(stock is 20 degrees right?) I was told to set them at these settings since i have no advance.

That's even more confusing. It sounds like you're measuring timing at idle, which on the surface makes the numbers make ense, stock timing is TDC leading, 20ATDC trailing. Setting the trailing to "25 degrees", then, would be retarding the timing.
WHich way is the 5 degrees, before or after TDC?

I was confused at first because most of us set timing with the revs over 4k, when mechanical advance is "all in". Some people recommend TOTAL timing of 24BTDC leading, 16BTDC (NOT ATDC!) trailing, but others of us don't like that. I run 20/10 and it seems to work OK.

If you have the vacuum hoses disconnected, you're only disconnecting the vacuum advance, which (IMO) isn't very important for what we need. You will still, however, have mechanical advance. That's why it's recommended to set timing at over 4k, because that way you are adjusting the timing in the rev range that matters.


my stock fuel pump has not had a problem supplying my weber(no bogging or hesitation) I do not have a return line hooked up.

Yeesh.

Jeff20B

iTrader: (13)

Yep, it's not ATDC! I once confused the two. ATDC does not mean advanced top dead center heh! I'm running a dizzy with only 20* of mech advance. I'm also running at 25* BTDC which gives me 5* BTDC at idle. I'm thinking about dropping down to 20* BTDC and seeing if I've got more high end. However I love my current low end. Can you say torque? (L/T split at 10*)

I also blocked my return line on my carb and installed a purolator diaphram type pressure reg. Now I'm running a bit rich. I'm going to put it down to 4.5 and see what it does for me. If it still doesn't help I might need to use the return line again. I also should get a new good fuel pump because I'm using the RB Facet pump.

RXcetera

Nothing wrong with the RB Facet pumps, as long as you can stand the noise.

As far as the stock fuel pump is concerned. I ran a Dellorto and street port exhaust on my stock 12A w/stock fuel pump for years. IF I would have kept the engine near redline for more than a few moments, I'm sure I would have run into some kind of fuel starvation problem, but for a 1/4 mile sprint, the stock pump was adequate. This doesnt mean much though... I'm sure I was running into a lean situation most of the time I was flooring it. I'd recomend to anybody who is running an aftermarket carb to switch to a better fuel pump, just to be on the safe side.

Jeff20B

iTrader: (13)

tick-tick-tick-tick-tick-tick-tick-tick-tick-tick-tick-tick-tick-tick etc.