Well, I think that today I will try a mod with the SC setup.

Alpine suggested that I increase the back-pressure in the exhaust in order to facilitate the retention of more boost in the cylinders...

In order to create this back-pressure, I have to fabricate a small restrictor plate that goes between the flanges in front of the 2nd cat.

So, what I plan to do is to get a sheet of thin metal (I have some @ home).. and then cut it into the basic shape of the exhaust flange.. then I will cut out a circle in the middle of about 1 3/4 inches in diameter.

After that, I will insert it between the two flanges and bolt it up...

Then I'll go for a test drive and see how it feels and I'll keep a close eye on the boost guage and on the Narrow Band o2 sensor..

If the car " feels " peppier then I'll go to the dyno tomorrow and check out what (if any) the gains/losses are.

wish me luck !

wow, good luck with that. i hope it works.

Dam bro your like the master of home depot performance.Hope it works out

good luck sir

although, I still think you should install the unichip

shawn :)

:iamwithst

Ford, might I suggest that instead of just a hole, you should taper the "restriction" so you are generating pressure while minimizing turbulance?

I hope you told alpine you havent installed the unichip yet....lol.

I hope you told alpine you havent installed the unichip yet....lol.

they know i have not installed it yet. but lets keep this thread on topic.

:)

forgot to say it

Good luck !

Steve I still think for that the supertrapp is the best option

Steve I still think for that the supertrapp is the best option


i've said it before and i'll say it again...


supertrapp = supercrapp.

:)

well, the weather was nasty and I got home a little later than I planned.. so this mod will wait until tomorrow after work to get done..

I'll keep everyone posted.

cool, lets see how it does.

I bet it'll hurt you up top if anything.

and maybe help at low rpm.

I agree that if its going to work well, a more aerodynamic shape should be used.

Ford, quick quesitons
1) Is your #2 cat intact? I remember it was not and just wanted to be sure
If it is gutted, and the restriction works, perhaps you should reinstall a cat (or just punch out part of the cat.

Oh. Good luck.

2nd cat is gutted.

is the second cat bolted on or whelded?

Ford,
May I recommend making different sizes. one at that size the other at 2 inches or even 2 1/4. I am sure your already thinking it.

Ford,
May I recommend making different sizes. one at that size the other at 2 inches or even 2 1/4. I am sure your already thinking it.

well, considering that i'm still using the stock mid-pipe section... it is already about 2 inches to begin with..

so i would have to start at 1 1/2 or so to get a feel for the mod ...

it I gain power, then i'll leave it alone, if I lose power, i'll change it for 1/4 inch wider, then i'll try again and so on...

:)

well, considering that i'm still using the stock mid-pipe section... it is already about 2 inches to begin with..

so i would have to start at 1 1/2 or so to get a feel for the mod ...

it I gain power, then i'll leave it alone, if I lose power, i'll change it for 1/4 inch wider, then i'll try again and so on...

:)
Oh yea I forgot about that.oops, ;)

We in the Northeast feel bad for your "nasty" Floridian weather. :P

Ok the mod is done.

I drilled about 8 holes with a 3/8ths drill bit and 3 or 4 smaller holes with a 5/16ths drill bit...

I decided to use multiple holes instead of 1 single hole because it was easier to just drill it instead of cutting out a circle...

:)

So far, I only drove it 1 mile in slow traffic so I can't say if there is a gain or not.. however, i did WOT in 2nd gear and the boost did go up 1/2 a pound...

I guess I'll be visiting the dyno tomorrow during lunch...

I'll keep everyone posted.

As to the question I asked in chat, just how farty is the exhaust note? I wonder if adding a second muffler after the cat would solve all your problems at once (faty and backpressure)

Ford...you're killing me with anticipation. I can't wait till you get all this worked out...I have faith in you. One day...I hope to jump on the SC bandwagon.

Keep up the good work man!

I just drove to work and i had a chance to really feel out the power at different throttle positions and gears...

I can tell for sure that there is a gain in mid-range torque at part throttle... that means that the mod is helping to make more power..

now, as to the peek power, I did a 1st gear roll-on WOT and i tore the tires up just after 4500 rpms and that has never happened before..

So I think there is also a gain in overall top end power also...

I will be going to the dyno during lunch today, so I'll keep everyone posted on the results... :)

Thanks Ford. Keep making the improvements!

ok, I went to the dyno .. the results are mixed... I think that the restrictor plate is affecting the wideband o2 sensor readings because most of the runs showed a very erratic reading ... It could also be that their wideband was defective ...

anyway... here is the dyno chart... as stated in the image, the red lines are last months dyno which is almost perfect as far as the air fuel ratio ...

for some reason, the blue graph shows a nasty dip in power and the air fuel is super lean... I dont really know what to say.. the dyno guy opened up the filter and checked it (in the wideband controller box ) and then it showed a super lean run .... I think they were having o2 sensor problems... either way, peek power is still basically in the same range as before except that on the street, I feel that the boost comes on higher than before at the same rpm .. so i will leave the restrictor plate in place for now. :)



http://nitrousworld.com/images/alpine_blower/May_2_2004_dyno_restrictor_1.jpg

Doesn't look like much change at all. Now get that unichip installed and then go back and dyno.

Ford...have you had a chance to get a ballpark on your 0-60 now? Very interested in finding out what you're getting.

Ford...have you had a chance to get a ballpark on your 0-60 now? Very interested in finding out what you're getting.

I have not been back to the 1/4 mile since the blower install...

I suppose that its a little better than before... the problem now is that it just spins the tires so easily that i have to short shift to 2nd to get traction ... lol :)

however, with a roll-on its not "as bad " but it still breaks the tires loose even from a roll.... :)

Does that mean you'll be getting wider tires to keep the spin down? :)

Does that mean you'll be getting wider tires to keep the spin down? :)


no. I can't use any wider tires.. if I do, they will rub on the fenders...

i'm currently using 205/15/55's.

R u lowered? I'm running 16's and no problems.

Sounds like you need the Zifiro widebody kit then...you got the money man go for it! Then add those 18's...oh yeah! ;)

215/50/15 and a unichip install is the answer.

R u lowered? I'm running 16's and no problems.

Sounds like you need the Zifiro widebody kit then...you got the money man go for it! Then add those 18's...oh yeah! ;)
Oh how much I want that damn kit.

no. I can't use any wider tires.. if I do, they will rub on the fenders... i'm currently using 205/15/55's.

and


R u lowered? I'm running 16's and no problems. Sounds like you need the Zifiro widebody kit then...you got the money man go for it! Then add those 18's...oh yeah! ;)

Uhhh... rim size and width aren't the same...
205/55/15 (23.9" diameter) is almost the same as 205/50/16 (24.1" diameter)which is almost the same as 205/40/17 (23.5" diameter) which is almost the same as 205/35/18 (23.6" diameter")... but all are the same in width...
The 205/55/15's are roughly the same diameter as stock (195/60/15) but ~1/2" wider.

anyway, none of this wheel / tire size crap has anything to do with this thread...

I just want to say that even though the dyno shows no gains in overall power or torque. .

I know for a fact that the car makes more boost at part throttle than it did before, and this means that the car is much MUCH more fun to drive..

I think that this is what Alpine intended for the car to feel like in the first place !

I am very pleased :)

Glad to see you happy man! you deserve it!

Exactly, I'm glad to hear it!

from my understanding, this restrictor plate makes the care more fun to drive for a few reasons..

#1. increasing back-pressure produces more load.
#2. if the engine is under more load, you get more boost...
#3. now there is more boost at any given load value.

So overall, the peek power did not increase, however the part throttle boost is higher and the car is much peppier and fun to drive ! :)

It looks as if the power and torque is peaking earlier, which does make it more fun to drive, and easier to break the tires loose.

All you need now is current 1/4 mile timings.