suganuma

i took my car to the drags for the first time a couple weekends ago. i was very disappointed in the times. on the first run the car wouldnt go into 3rd - tried to rush the shift too much i guess.

all of my times were pretty crappy....and i thought maybe it was due to altitude, but another 3rd gen with just downpipe and the apexi computer ran a 13.78 and then a 13.54

here are what my timeslips looked like.....

R/T---------.648-------.674-------.448
60'---------2.501------2.432------2.615
330--------6.632------6.362------6.665
1/8-------10.143------9.672-----10.048
MPH-------68.93------74.82------73.36
1000-----13.132-----12 477-----12.989
1/4-------15.582-----14.825-----15.508
MPH-------93.83------96.74------89.89

on the 2nd run the a/c was accidentally left on and theres a big difference in the times....

needless to say something is WRONG

both the times and the MPH is way low

the PFC was showing some VERY high intake temps and comparing numbers to that same guy in the area with just driving around his are much lower than mine. i think this is mainly due to my ducting being crushed by the massive fluidyne radiator.

still seems like something else is wrong though.....it didnt feel like the high end was there in 3rd and 4th....

mods are m2 intake, dp, high flow cat, cb, apexi PFC
the rest can be seen at the link in my sig...

can anyone help?????
any ideas??

GsrSol

Those suck dude. Looked bad from the get go, 60' are terrible, should atleast be a 2.1

On the 2nd run you left the A/C on right, well you know the fans come on with the A/C and probably cooled it down a little so I would think it was just too hot. However I would think a 9.6 and 14.8 is good for having the a/c on.

Nike178

Yea, i'd say something is defenetly wrong. With those mods u should be running at least low 13's. Do u have a boost gauge and if so, what were u boost patterns? What were u launching at and what technique did u do? Did u get a lot of wheel spin or something cause those 60' times are horrible. I ran my stock fd 3 weeks ago and got a 14.0 @99mph. Something is defenelty not right.

suganuma

boost was at a steady 12.5

tried launching all kinds of different ways...

shift points :

1: 8k
2, 3: 7k

launch:

1st run 4000 slip clutch out on 3rd light
2nd run thought i was getting too much wheel spin so i slipped it out at 3500 on the 3rd light
3rd run i took my buddy's advice and just dropped it at 4000 and got TONS of wheel spin and shifted at 7500 instead of 7000
but on that last run obviously i rolled out of the staging lights....

and ya, i realize those 60ft times are terrible....

to give you an idea of my RIDICULOUS intake temps....before one run i saw 71*C - think taht was the last one.

the 2nd run i didnt have to wait in the staging lanes that long so i think that was an attibuting factor to heat soak of the IC as well.

it was something like 70s-80s outside....not very hot at all....

i blame my dinky stock IC and the screwed up ducting for the IC heat soak....as well as the fact that i didnt have a bag of ice or anything to slap on it.

the thing that sucks is that i let my car cool down with the hood open between runs just like my buddy who ran the 13.54....

MPH times should be in the 110+ area....1/4 mile time should be high 12/low 13s as was already stated. i was expecting a low 13 at the altitude.

i wasnt hooking up like my friend since he was using 245 width kumhos and i was on the michelins i got with the car.....

what i REALLY dont understand is how i blew away a low 13 second supra 2 nights before....i was seeing 40-50*C intake temps that night....

spyfish007

Just remember the AC will kick off under heavy load.

It just doesn't seem like you are making any sort of real power. With that bad of 60 ft times your MPH should go up indicating you have the power .... but yours are still low for your mods. I don't think something is setup correctly with your engine/tuning/etc.

suganuma

i KNOW something is screwed up with the tuning/engine b/c i dont think intake temps could cause SUCH a difference. i still wont eliminate it as a definite factor...but something else has gotta be wrong.....

my pfc maps can be found in the PFC maps section of the forum
https://www.rx7club.com/vforums/show...threadid=10509

what could be affecting high end power if im still getting strong boost??

suganuma

whats that old correlation of intake temperatures to HP....??

spyfish007

I believe 10 F degrees = 1 HP

thatoneguy

There is definitely something wrong with your car. I have almost the same exact mods as you and I"m trapping 111mph in the quarter mile. Try reseting your PFC or something.

SPOautos

Your clutch is gone......you have too many mods to harness the power with the stock Mazda clutch. I ran 12.3 with those mods, I had a stock clutch with about 20K miles on it and it crapped out shortly after, it wouldnt slip but there was a power loss kinda like the power just wasnt getting thru to the wheels.

Would also explain it not going into 3rd gear good. Thats kinda how mine would do but in 2nd gear.

You need a good aftermarket clutch and to be on the safe side you might want to consider a compression test on you engine.

Later,

suganuma

stephen,
i was thinking the same thing about the clutch. its a newer stock clutch - it was replaced before i got the car, so im not COMPLETELY sure how many miles are on it. my engine has around 10k on it so at least that many miles.

i know that the clutch isnt holding up to the power.....when coming up to colorado i tried doing a top speed run on a lonely tx road and it would hit 150, but the revs were all over indicating a slipping clutch. i know im right at the limits of the clutch....just didnt think the effects would be that noticeable.

i am currently saving up for either the greddy or apexi FMIC or the M2 large SMIC (havent decided yet)
as well as the SR ACT street/strip - 8.5 lb flywheel deal

i wont be driving much pretty soon as the snow season is about to arrive so itll probably be spring when i put the clutch on......unless i get some money REAL quick b/c while the trannys lifted i want to get my 5th gear synchro fixed as well.

anyone else think its the clutch or have any other ideas/experiences???

suganuma

results from my last compression test in august were posted....no one gave any feedback though.

https://www.rx7club.com/vforums/show...ht=compression

mmaragos

I am probably not pushing as much power, but I was having the same issue when pulling toward redline (4500+). Definitely noticable, but I could see how that may develop over time and be less noticable. I had a high mileage clutch, then started to upgrade (intake, exhaust, PFC, etc.). Overpowered the clutch pretty quickly and I was able to notice it immediately.

Just finished installing an ACT clutch and lightweight flywheel (about 12 lbs w/counterweight) over the weekend. Replaced the fluids too...good thing - nasty. I am just about ready to road test, I also installed a new 4-wire O2 sensor (need to mount the gauge and finish the wiring).

Flywheel was a b*tch to get off (broke one puller)...then after some frustration I took a mallet and hit it four times...it popped off (good thing I had the nut there).

In addition, the rear oil seal was toast...which probably didn't make conditions too favorable for the clutch, although the surface looked free from oil.

jimlab

Suganuma, SPOAutos is right. Your clutch *HAS* to be shot, and I don't care how new it is.

Even if you don't have enough experience to launch well, your trap speed should still be much, much higher. My Supra trapped 89-91 mph in the EIGHTH, and 114-115 at the end of the quarter. Even with the stock automatic and converter, I was still getting 2.0-2.1 60 foot times, even on my (best) 12.46 run. This is with street tires, of course.

An RX-7 with a manual transmission should be getting sub-2.0 60 foot times with practice, but even without, you should be in the 2.1-2.2 range easily. The fact that you're up around 2.5-2.6 tells me that your clutch is giving up on the launch and that at that point, it's shot for the rest of the run, which is why you didn't feel the right power in 3rd and 4th, where load is even more likely to make the clutch slip. I would have expected that you (and everyone else) would have smelled it?

At 12.5 psi, it's probably holding on the street, but at the track, after a burnout (if you're doing one) and the launch, it's shot. You'll eventually need a new clutch anyway, and sooner if you drag race some more, so I'd start looking for an upgrade.

If you have the rev limiter disabled in any way, I'd start looking for an upgrade NOW. When it lets go, you won't be expecting it, and you'll (like I did) hit 9,000+ rpm in a hurry. I had my Crane HI-6 set to 0 rpm on the rev limit because I thought my ECU was handling that job. Turns out the rev limit was removed by M2 Performance when they did my programming. About 3 seconds after I let out (it seemed that long) the tach finally fell back into the range of the gauge, so I know my engine went FAR higher than 9k. A couple months later it spit out a corner seal at 70 mph, just cruising in traffic. Killed the engine and took out the rear turbo.

Do the smart thing, get yourself a decent clutch ASAP.

ACT, CenterForce DF, whatever... I do NOT recommend the Racing Beat street/strip clutch, if it's still available. The Mazdacomp upgraded pressure plate is also pretty much worthless. Stick with a full aftermarket clutch and pressure plate.

suganuma

most of you seem to have decided that it is definitely my clutch....

but a *reputable source thinks its not the clutch at all, but something restrictive in the exhaust.
maybe a clogged cat

other suggestions have been made are possible tuning problems
carson says my maps look rich to him, but O2 voltage didnt really notate that. stock sensor is pretty inaccurate though.

i am running the bonez high flow cat currently, but i will be putting on a midpipe fairly soon. my wastegate is NOT ported so thats also a fear in the whole process of trying to diagnose the problem.

y'all have any ideas besides the clutch??

suganuma

leading ignition....maybe problems besides that crossthreaded plug i just fixed?...

GoodfellaFD3S

iTrader: (213)

Nic, I wouldn't (repeat would not) go w/a midpipe. As the weather gets colder Im getting worse and worse boost creep, and I have a ported wastegate. With the stock wastegate I would imagine you'll see upwards to 20 psi, which is not good for engine longevity I don't know why your high flow cat would be clogged....

Gimme a call if you wanna talk about it; maybe you, Carson and I can conference call and figure it out

Rich

SPOautos

The stock clutch can NOT handle that much power. It wont really slit read bad but the power just cant get through. Mine was acting the same way. Here is the deal......EVEN IF YOUR STOCK CLUTCH IS IN PERFECT HEALTH ITS NOT STRONG ENOUGH FOR YOUR MODS

For other options you might want to check the clutch slave cyl if you think you clutch itself is ok but I can tell you that the stock clutch is more than likely not holding the power.

Your tuning might be rich but its not going to be so rich that your loosing 2-3 seconds thru the 1/4. If your tuning was that bad you prob couldnt run the car. When I made my 12.3 with those mods I was running the PFC base map that comes with the computer and it was at 12.5 psi of boost.

How old is you hiflow cat??? Do you still have the air pump hooked up to it??? Its possible that the cat is clogged but since your not running the stock cat its unlikely unless you've put a ton of miles on it. Get someone to rev it up real hard and you put you hand at the exhuast tip and see how the air flow feels. It should be a nice hard rush of air.

Why did they say that they dont think your clutch is the problem??? Did they test it or speculate???

Check the clutch slave cyl, if it is stuck it can cause probs with the clutch not fully engaging, I think its a $50-$100 part from Mazda and cake to put on.

The only other think I feel like it could be is compression. You might want to get a compression test.

Also look for a IC hose leak, this might sound funny but you can still be leaking alot of boost and run 12.5 psi. the difference is that you'd be hitting 12.5psi with a small volume of air instead of alot of air. I had a boost leak where my car was showing 13psi but felt slow as **** and it was a leak in the IC pipes. The coupler that holds the crossover pipe to the Y pipe had a tear in it under the clamp. It was hard to find because you actually had to pull the coupling and remove the clamp to see the tear. You might want to try that with all you IC pipes.

Good Luch,

SPOautos

BTW - When you say VERY high intake temp, how high are we talking??? Also what was crushed by the radiator? If your intake cant breath that will make a HUGE difference because you engine is suffocating (sp?)

suganuma

IC ducting is getting smushed by the width of the fluidyne. M2 intake fits fine - no interference.

by HIGH intake temps i mean that i saw a high of 72*C in the staging lanes before i went to run and i was sitting there with engine off and a/c fans ON like i did every time. (you can put your jaw back in place now) it would cool down during the run....but not much. didnt worry too much since i was running 104 octane mixed with a little pump gas. i am seeing higher intake temps (usually 10*C higher) than another guy in the area on the same nights.

i'm going to try and get ahold of some aluminum sheeting and see what kind of HELP i can provide to the IC. what intake temps do y'all see over ambient?

clutch slave cylinder...hm...thats an idea. how do i "check" that while on the car??

rich, ya i decided last night that i will probably not buy the midpipe. gotta save up for IC and everything and chris at RP says hes never seen one of the bonez's on the 3rd gen just burn out. its been on there since january stephen. any my most recent compression test i posted a link to above.

here are the results from august re-posted though

Rear:
8.6
8.4
8.6
Front:
7.8
7.9
7.6

so now the list of possible reasons why my times were so slow consists of:

1. leading ignition
2. bad IC ducting and dinky IC (high intake temps)
3. clutch overpowered
4. clutch slave cylinder not engaging clutch all the way (need more info on this)

anyone else want to chime in with ideas??

SPOautos

I think if you coils were that bad you would get bad misfire at higher rpms. Believe it or not you intake temps are not out of the norm for the stock IC that is heat soaked. In traffic its not uncommen at all for them for reach 70C+

I think its going to comedown to either a leak somewhere in you IC pipeing like a tear in one of those rubber couplings. I would take everyone off and inspect it. Oh yea, I remembered another thing, make sure the Y pipe to crossover pipe coupling is real tight because it could be coming up under boost, venting some boost out then dropping back down if its real loose.

I say check all your IC pipes and couplings for cracks, tears, and tightness. Also look into checking the clutch slave and you really do need to upgrade the clutch. The clutch may not be the entire problem but I gaurentee your mods have to much power for the stock clutch.

Your compression test is awsome so unless something has happened since then you should be ok.

Later,

Tobal

man.... something wrong over here too w/ my drag times.. i finally took it out tonight and got a average of 14.6 1/4 time. I have DP/Catback. i was hoping too look for something in 13s or low 14s at least. But kinda hard to get traction. very differnet from the streets. but 4 runs i ended up with like. 14.7s 14.6s 14.5s...seems kinda bad.. i was compared with some honduhs

LUPE

14.7's?

My stock FD went 13.40 @ 102 mph..........

You've got something seriously wrong.

Marshall

Yes Eric, something WAS definately wrong with his car.....5 YEARS AGO!!!
LOL

LUPE

Eh 5 years........ 5 days....... what's the difference