I swear i've about had it with my car.. every time i go to the track i leave dissapointed. We made it up to commerce last night, only got 2 runs in, and my best run was a 15.260 in the 1/4. I've been battling this for over a year now and cant figure out whats wrong.. i've changed knock sensors, o2 sensors, plugs, my blow off valve.. but nothing seems to correct the problem. I'm running a v2 and a 3.33" pulley. The SC is in perfect running condition. One thing i notice when i'm giving it hell, is that in 3rd gear at about 5500 rpm, its starts to bog out, or thats what it feels like. Could it be my injectors?? Could my engine just be tired? Theres guys running better times than me that are bone f-cking stock!!! PLease throw some ideas at me as I am about ready to give up on this car. I will entertain ANYONES comment

 

Has anyone driven the car at the track and given you any feedback?

 

Do your have your T-rex fuel pump running all the time? Or are you still relying on the switch in the kit?

 

OK, this is a little over my head but you said you'd entertain it

Do you have a boost gauge? Maybe your not producing the boost your expecting. There could be a leak or a problem your not detecting.

Can you reconnect the stock intake and put the stock AC/Alternator belt back on and go do a run. Lay down some stock numbers to see if the issue is with your motor or the SC. (I don't know if this is a good idea, or if there are more things you need to change to run without the SC, but it seems like a good way to narrow down the problem)

And if these ideas are stupid, feel free to ignore me

 

I'm sorry but this has nothing to do with your post, mzmtg tell me that isn't a real car in your sig.....please or else I'm going to have trouble sleeping tonight......

 

 

Simple suggestion... have you checked your y-pipe flex section?

 

I'm assuming you haven't dynoed tuned it yet? IIRC when Loren did his first SC pull it was like 195whp from 165whp~ without the SC. You will have to tune SC, you can't just bolt it on and expect good gains. Also what elevation is commerce at and what ET's do other cars run? For example if F-bodys and Vettes are running 14s then its a slow track. However if they are running 12-13s then you have a driving problem. Can you post the full info from the timeslip like 60', 330, 1/8 ET/trap, 1/4 ET/trap?

 

Here are the times from a few other members that raced at the same track as bosco.. They both have NOS

http://forums.maxima.org/showthread.php?threadid=126566

Also bosco did you ever have your SC dyno tuned?
Hope you get that problem fixed.

 

Commerce is roughly at 1100 feet elevation. Don't really think it's a slow track since my friend in his E46 M3 has run a best of 13.3x so far.

 

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Its ok , just sell your maxima, and i would be happy to take the blower of your hands

 

Reeally!?

I just bought Loren's S/C and he made it VERY clear to take it to a Dyno and tune the Cartech FIRST thing...guess that's why!

IanS

 

Hello:

Are you using gasoline with MTBE or Ethanol additive?
These "release oxygen" during the combustion process which effectively lean out the overall combustion process (at least as judged by the O2 sensor) The higher the temperature, the more exponential the effect. Your air:fuel mixture may be adversely affected by high temperature using(forced to use) ethanol or MTBE.


Are you using an automatic or 5 speed?
The supercharger has parasitic losses and does not provide boost at low RPM. The torque converter acts as a torque multiplier. Adverse effects such as losses of torque to the wheels at low RPM on a 5 speed will be felt even more so on an automatic for the same mods.


When you are lined up at the track, are you sitting still and idling for a long time before you make the 1/4mile pass? idling the car for 10 minutes will raise the intake temperature up to 50 degrees F which can cut several percent off the power potential.


Are you using "big wheels" or very wide tires such as 225 or 235 size tires? If so, how is the alignment and also the scrub radius?
If you are using significantly wider wheels and tires, you will get significantly more rolling resistance drag at high speeds (exponential rolling resistance drag effect with speed).
Beyond the width of the wheels and tires, the weight makes even more difference.

Finally, the Maxima is not a "sports car". It is marketed as a "4 door sports car", but that is just marketing. Its not really slow, but its not built to be really fast either. So don't waste your time and money.

Hope this helps..

 

that's my vote....check your y-pipe flex section...obviously you have a restriction somewhere in the intake or exhaust system...could be the cat too....

 

What size rims do you have? Large rims could slow you down, shouldn't slow you down that much but it could be your problem.
Good Luck,
Paul

 

Sorry to get OT, but I have my pet peeves:

I think Don, Loren, TurboMax, and a few others would disagree with the statement above.

I believe the "4 door sports car" marketing to be pretty close to the truth.

This car is made with a lot more, and the VQ can handle alot more, than any of it's direct direct sedan competitors - Camry, Accord, Galant.

It also beats the pants off or at least keeps up with most import "sports cars" stock. Integra, Eclipse, NA Supra..

Our engines are BUILT for boost....they handle anything we throw at them. The problem is the sedan "luxury" tranny, not the engine, and that can be fixed with a Tranny Cooler and a VB Mod.

On the other hand, it is NOT a TT Sura or a Camaro SS.
Also, it is not a Cadillac or Q45.

So I think "4 door sports car" fits the bill.

It's perfectly balanced.....which is why I bought it. It's a comfortable sedan with some nutz and dependability.

If you don't like your car because either you want more sport, or more luxury, then buy another car.

For me, this car is happy in both worlds. ("4 door/sports car")

IanS

 

i fixed it to where its on all the time.

 

I know its not the blower because my boost guage says i'm pushing 9 pounds. It never drops off either.

 

what would this do?

 

havnt dyno'd since i replaced the knock sensor. I did at maxus when i first got my SC, and it was at 160 hp. I was ****ed and thought it was the knock sensor... i must have been wrong though. There are stock max's that blow my doors off at this track

 

I dont mean to sound like an idiot, but there is nothing you can really tune on our cars is there?? you cant mess with the timing, and to change the fuel pressure you have to change pumps?? correct me if i'm wrong. Maybe this could be my problem.

 

Search and ye shall find

Shrinking Flex Section

If you can, take down your y-pipe and look through it to see if its restricted. You can't tell from the outside.

 

Strange. With that pulley you should be pushing at LEAST 240-250 at the wheel. If properly tuned, you should be at 250-260.

Man, I hope I don't have this kind of trouble when I install my SC.

It has to be something with the blower. Even with a restricted flex, he'd probably still be at 200hp, or a knock sensor or any of those things...correct? (I'm asking, not telling).

IanS

 

two guesses:

belt is slipping (but sorta ruled out by the boost numbers).. what rpm are you hitting 9lbs?

fuel problem, check the pressure under WOT with a guage.. i;ve experience a bog if you will,, usually in the 3k to 4k range. make sure all the fuel lines are free and not bent, aux pump is running full time and oem pump fuse is good.

i haven't experienced the flex section dilema but its worth a shot to check.

have you gotten any codes?

 

Take the comment back with the heavy wheels with a damaged YPIPE and heavy 28lb tire 25lb rim my best time at the track was 14.6!!, and your running 15's are you auto or 5 speed.


Bosco listen my **** is totally out of tune if you wait we both can tune our S/Cers together. So your not the only one disappointed my best time so far was 14.5 with a damaged Ypipe. So let me get up there and lets see if we can figure out these problems. I am no technician but I dont give up so easily.

Check your Ypipe it wont hurt to remove two 14MM nuts and a flashlight to check. If not then see if you had a leak somewhere. I had a airleak it was coming from the ambient air sensor.

 

I also have a fuel pressure gauge that you can connect to the top fuel rail to check to see if your getting enough fuel pressure, at 9PSI you should be getting about 90PSI fuel pressure, and if I am wrong somebody thats boosted correct me. At 10PSI I am getting 100PSI with the FMU disk 8:1 disk. If you need to borrow it I can fedex it to you and you connect it have someone ride with you when the highway is somewhat empty punch it and have that person read the fuel pressure at 9PSI. When I go to the June 29 Meet you can just give it back. Thats what I did. My problem was not solved there my Ypipe was damaged.

 

It hits 9 pounds at about 6 grand.

I have a fuel pressure guage.. just need to hook it up. I just have no where to mount the damn thing. I guess that is next though.

 

I'm gonna hook my fp guage up when i get back in town. i'm leaving wed. to go to amsterdam and will be gone for a week and a half. I think i may have too much fuel because i'm using the walbro fuel pump also. are you using it along with the s/c pump?

 

No no I am only using the Vortech FMU that came with the supercharger.
I am thinking of getting one of those Walbro fuel pumps vice using this Vortech FMU. All I can tell you is that it takes time to tune the car, think about it I was running 15.1s at the track too and I had a worse attitude then you did, problem one I had a leak, problem two which I never thought about Y pipe was shot and is been two months and I still have not got it back.




Iansw, I got the fuel gauge bout about 6 feet of hose split in half and put it under the windshield wipers used some strong mailing tape and taped it to the window for 2 runs. I then tucked in the engine bay if you clik on my home page you will see the long snake just all over the place.

 

I've got the Cartech FMU, it's completely adjustable.

You should go with that. A Fuel pump won't do what a FMU does, they're 2 different things.

IanS

 

it was his y-pipe

cattman.

sorry didnt mean to bring it back up bosco, just trying to help out anybody else who might have the same problem.

 

That's great he got it fixed...

Nismo:

Any idea what Loren tuned to get his SC running right? I have his SC now, and I can't get over 6lbs of boost with the 3.25" Pulley, and I'm only getting 231hp.

Loren has thrown ideas at me, but nothing has worked.

I already ripped apart my exhaust, and It's not my Y-Pipe.
I also had 2 mechanics check for leaks, sealed every joint (MAF/TB/Ambient air) with gasket sealer, and no luck.

I even completely took off my MEVI and resealed that.
(MardiGrasMax has confirmed he lost no boost, only gained hp with the MEVI, so it's not that)

Anyone know what vacuum I should be pulling with the SC at idle?

I'm sure most of you've already read my threads on this, but I just can't stop obsessing over it.

IanS

 

If your boost guage is right then the only thing it could possible be is that your belt is slipping at high rpm's, or the blower is messed up. If the belt is not slipping then you should be pushing more than 6 pounds!!