Supercharged/Turbocharged The increase in air/fuel pressure above atmospheric pressure in the intake system caused by the action of a supercharger or turbocharger attached to an engine.

Thinking of going 3.125"

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Old Sep 17, 2003 | 01:20 PM
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Thinking of going 3.125"

At the moment I have the 3.33" pulley with the stock FMU and stock fuel pump.

If I go 3.125" I guess I'll have to get the 8:1 disc from Vortech?

Pulley:
http://www.vortechsuperchargers.com/...Code=2A036-312

8:1 kit?

http://www.vortechsuperchargers.com/...Code=6Z170-020

Will I need to get a Walbro fuel pump?
belt size?

After all of this would there still be lag until 3000rpm as usual?

Also would I need the Apexi SPC?

Sorry for the multiple questions!
Old Sep 17, 2003 | 01:31 PM
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to all that!

Would it be required to get 370cc injectors before making that move?
Old Sep 17, 2003 | 01:44 PM
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For the V2?

You'll need the 8:1. Stock fuel pump will work, belt size is smaller I believe, however you'll have to look it up for the exact one. You may run slightly more rich with the 8:1, however I view the S-AFC as something that can be added to *all* supercharger kits for a bonus on +hp. So again, it's an option and probably a fairly good one.

It will work if all you buy is a belt, FMU disk and pulley, however S-AFC, larger injectors, better fuel pump is all stuff that can be added, but is not necessary.
Old Sep 17, 2003 | 01:53 PM
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Originally Posted by ereet
For the V2?

You'll need the 8:1. Stock fuel pump will work, belt size is smaller I believe, however you'll have to look it up for the exact one. You may run slightly more rich with the 8:1, however I view the S-AFC as something that can be added to *all* supercharger kits for a bonus on +hp. So again, it's an option and probably a fairly good one.

It will work if all you buy is a belt, FMU disk and pulley, however S-AFC, larger injectors, better fuel pump is all stuff that can be added, but is not necessary.
Thanks! That sounds good! Looks like I'll start with the basic stuff.
Old Sep 17, 2003 | 04:19 PM
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I'm running the V2 with that pulley. I'm still using the "stock" FMU... Isn't the V2 kit come with the 8:1 already (as opposed to the V1 with 6:1)?

I'm only running the Walbro w/o the inline... EGTs still seem good (maybe too rich)...

You'll need the 705 belt for the V2 kit.

My base FP is probably 42+ because I haven't put in my SARD FPR yet... Hopefully this weekend so I can dial it back to 34psi.
Old Sep 17, 2003 | 05:34 PM
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I always assumed the V2 came with the same 6:1 disk, but I could be wrong. I always thought stillen botched something and sent out a pile of 8:1's instead of the 6:1's since I've heard people on here complain about getting the wrong one.
Old Sep 17, 2003 | 06:25 PM
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I'm running the 3.125 on my car right now.

Stock Injectors, stock Fuel Pump.

Using the Cartech Adjustable FMU however.
Old Sep 18, 2003 | 05:25 AM
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Originally Posted by iansw
I'm running the 3.125 on my car right now.

Stock Injectors, stock Fuel Pump.

Using the Cartech Adjustable FMU however.
What fuel pressure do you guys see with that pully?
Old Sep 18, 2003 | 07:22 AM
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I'll tell you next week when I get a FP Gauge installed.

Old Sep 18, 2003 | 07:35 AM
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My concern is this:

3.125" is going to be my next pully upgrade I think. But I don't want to risk locking an injector or anything. I'm not to thrilled with the idea of pushing 100psi+ through the stock ones.

Next spring I'm going to do a major fuel system upgrade (injectors, SAFC, etc), but until then I'm going to stick with what I've got.

If I'll be safe with the stock fuel system on the 3.125" then I'd put it in now and upgrade the fuel system later.

If not...I guess I'll wait for both.
Old Sep 18, 2003 | 08:58 AM
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All I can attest to is the WALBRO (despite the higher base FP due to OE FPR) can handle the 3.12" pulley on the V2. I've had it for about 6 months?

Although I'm not sure I have an 8:1 FMU (whatever I got with the original V2 kit).
Old Sep 18, 2003 | 09:00 AM
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Originally Posted by Chunger
All I can attest to is the WALBRO (despite the higher base FP due to OE FPR) can handle the 3.12" pulley on the V2. I've had it for about 6 months?

I've finally got all my parts for the CAI so that's my next project.
I'm thinking exhaust now....
Old Sep 18, 2003 | 09:07 AM
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Originally Posted by BlackCat
I've finally got all my parts for the CAI so that's my next project.
I'm thinking exhaust now....

Oh... I have the CAI too (whether or not that actually raises boost levels?)...

I also have the Proflow bored out throttle body...
Old Sep 18, 2003 | 09:14 AM
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Originally Posted by Chunger
All I can attest to is the WALBRO (despite the higher base FP due to OE FPR) can handle the 3.12" pulley on the V2. I've had it for about 6 months?

Although I'm not sure I have an 8:1 FMU (whatever I got with the original V2 kit).
What fuel pressure do you get? I've got a Walbro, so I'm not worried about the pump, just the injectors.
Old Sep 18, 2003 | 09:26 AM
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Originally Posted by ejj
What fuel pressure do you get? I've got a Walbro, so I'm not worried about the pump, just the injectors.

Sorry, no FP gauge. Though I will have one on the SARD itself when I install it soon.

For that matter... no boost/vacuum gauge...
Old Sep 18, 2003 | 09:27 AM
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Originally Posted by Chunger
Oh... I have the CAI too (whether or not that actually raises boost levels?)...
It will be a while until I get another free weekend before I can spend time and cut the fender wall. Looking forward to seeing if it makes a difference in boost numbers and in power.
Old Sep 18, 2003 | 09:46 PM
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3.125 is pushing it...

IMHO, 3.125" pulley will put you over the edge. If we can still find it, I researched doing this about a year ago. There are several posts on this. It also lists how to do it safely/correctly. It is not recommended for a daily driver Maxima to just slap on the pulley and belt.

3.33" is the safest, smallest pulley for your money. You can go smaller but the total co$t goes up faster than Horsepower

Cheers!
Old Sep 19, 2003 | 08:08 AM
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Well, if you need it, I have a S-afc and will have a Walbro 255lph pump - 2 months old, had it replaced under warrenty....
Old Sep 23, 2003 | 07:16 PM
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That was the setup I had and I have the Walbro. You don't want to run lean and detonate....trust me.
Old Sep 27, 2003 | 09:30 PM
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Originally Posted by iansw
I'm running the 3.125 on my car right now.

Stock Injectors, stock Fuel Pump.

Using the Cartech Adjustable FMU however.
Stock fuel pump? So if I go 3.33 on a V1 I will not have to install my Walbro? That would be great and one less hassle. I have heard mixed reviews of the walbro pump and it's reliability. I will also have a AEM FPR, and Car-Tech FMU, what do you think?
Old Sep 27, 2003 | 10:20 PM
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Originally Posted by ejj
My concern is this:

3.125" is going to be my next pully upgrade I think. But I don't want to risk locking an injector or anything. I'm not to thrilled with the idea of pushing 100psi+ through the stock ones.
100psi!? Of fuel pressure!? I see like ~80's - low 90's max at WOT, and i'm running the 3.125". I highly doubt you would see 100+psi of FP.

My setup consists of:

-V1 blower
-3.125" @ 9.5-10psi
-8:1 FMU
-Custom CAI
-Walbro Hi flow FP
-AEM FPR
-Apexi S-AFC


I am waiting to get my intercooler installed b4 I dyno tune, b/c I would need to re-tune if I dynoed b4 the FMIC install anyways. So I am still very untuned. I set the base FP at 33.5psi, but didn't feel safe, so I have temporarily set it back up ~40psi. I'll lower it back down to 36psi. The thing is, with the AEM FPR, it has to settle in. For instance, if your at a normal warm idle of 600rpm, set the FPR at 36psi, and go driving, it will settle down to like 33psi. Its kinda annoying, but the stocker did it a little too.
Old Sep 27, 2003 | 11:19 PM
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Originally Posted by Street Reeper
Stock fuel pump? So if I go 3.33 on a V1 I will not have to install my Walbro? That would be great and one less hassle. I have heard mixed reviews of the walbro pump and it's reliability. I will also have a AEM FPR, and Car-Tech FMU, what do you think?

I have the Cartech, no FPR, and stock injectors and I have used the Cartech to tune perfectly to 12.1:1 across the band (with some very slight (never over +/-2%) tuning on the Apexi AFC.

I do have a Walbro coming in, however - but that's because I'm going to 300zx Injectors, JWT ECU, removing the Cartech, and adding a 2.87" Pulley on top of N20.

IanS
Old Sep 29, 2003 | 05:43 AM
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Originally Posted by Craig Mack
100psi!? Of fuel pressure!? I see like ~80's - low 90's max at WOT, and i'm running the 3.125". I highly doubt you would see 100+psi of FP.

My setup consists of:

-V1 blower
-3.125" @ 9.5-10psi
-8:1 FMU
-Custom CAI
-Walbro Hi flow FP
-AEM FPR
-Apexi S-AFC


I am waiting to get my intercooler installed b4 I dyno tune, b/c I would need to re-tune if I dynoed b4 the FMIC install anyways. So I am still very untuned. I set the base FP at 33.5psi, but didn't feel safe, so I have temporarily set it back up ~40psi. I'll lower it back down to 36psi. The thing is, with the AEM FPR, it has to settle in. For instance, if your at a normal warm idle of 600rpm, set the FPR at 36psi, and go driving, it will settle down to like 33psi. Its kinda annoying, but the stocker did it a little too.
I'd figure the 3.125" would give me (V2) 11psi.

(34/2) + (11*8) = 105psi.

Not a problem though...I've got Z injectors in the mail.
Old Sep 29, 2003 | 07:05 AM
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Originally Posted by ejj
I'd figure the 3.125" would give me (V2) 11psi.

(34/2) + (11*8) = 105psi.

Not a problem though...I've got Z injectors in the mail.
So Eric, you gonna do the injector swap this weekend like me? We can compare notes next Monday.
Old Sep 29, 2003 | 07:11 AM
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Originally Posted by Stephen Max
So Eric, you gonna do the injector swap this weekend like me? We can compare notes next Monday.
No, I don't even have them yet. They should show up today or tomorrow. When I do get them I'm going to get them cleaned (http://www.cruzinperformance.com/fuelinj.html), because they're used and I want to be sure that they're in good shape. On top of that, I still need to get the SAFC installed and the 3:1 FMU disc in the mail.

Soon though.
Old Sep 29, 2003 | 08:11 AM
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Hey guys! How do I check to see what size FMC disc I have? Do I have to open it up to take a look?
Old Sep 29, 2003 | 08:13 AM
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Originally Posted by BlackCat
Hey guys! How do I check to see what size FMC disc I have? Do I have to open it up to take a look?
Yes. You'd have to measure the disc and you can figure it out from its size. There was a table of sizes to ratios posted, but I don't know where, and haven't found it.

Also, if you know your redline PSI and Fuel Pressure, you could figure out which disc you're using.
Old Sep 29, 2003 | 08:31 AM
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Originally Posted by ejj
Yes. You'd have to measure the disc and you can figure it out from its size. There was a table of sizes to ratios posted, but I don't know where, and haven't found it.

Also, if you know your redline PSI and Fuel Pressure, you could figure out which disc you're using.
I don't have a fuel pressure gauge hooked up.
Thanks ejj, I'll do a search for that table.
Old Sep 29, 2003 | 08:46 AM
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Originally Posted by BlackCat
I don't have a fuel pressure gauge hooked up.
Thanks ejj, I'll do a search for that table.
If you're running 10 psi of boost with the 3.125" pulley, you really should have a fuel pressure gauge. And an EGT gauge.
Old Sep 29, 2003 | 09:12 AM
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Found it:

FMU Disc Size
4:1 = 1.59"
6:1 = 1.85"
8:1 = 2.22"
10:1 = 2.47"

I've only seen 7 psi boost with the 3.33" so far. At idle without blipping the gas pedal its at 16 in HG.
Old Sep 29, 2003 | 05:38 PM
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hey all, im going to be running a 3.25, just ordered a Walbro, also wondering if the stock plugs are fine to run with the 3.25 pulley, i also decided not to get an EGT right now but just go with a boost gauge and my a/f gauge and the s-afc2. Any other recommendations to keep it on the safe side?
Old Sep 29, 2003 | 06:14 PM
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One step colder lpugs and you HAVE to get a EGT. If not you can & will blow your motor....I did.
Old Sep 29, 2003 | 06:27 PM
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Originally Posted by MaximaRider
hey all, im going to be running a 3.25, just ordered a Walbro, also wondering if the stock plugs are fine to run with the 3.25 pulley, i also decided not to get an EGT right now but just go with a boost gauge and my a/f gauge and the s-afc2. Any other recommendations to keep it on the safe side?

for SC, forget about the A/F gauge unless you spend on a really good one. Boost gauge is optional IMO....you wont overboost with the SC.


I agree with Latinmax....
you must have an EGT


and I highly recommend fuel pressure gauge.
Old Sep 29, 2003 | 06:54 PM
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Originally Posted by BlackCat
Found it:

FMU Disc Size
4:1 = 1.59"
6:1 = 1.85"
8:1 = 2.22"
10:1 = 2.47"

I've only seen 7 psi boost with the 3.33" so far. At idle without blipping the gas pedal its at 16 in HG.

7psi!? Holy cow! V2 right?? You should be seeing 8-9psi. With a 3.125", you *should* see 11psi.
Old Sep 29, 2003 | 07:27 PM
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Originally Posted by [maxi-overdose]
for SC, forget about the A/F gauge unless you spend on a really good one. Boost gauge is optional IMO....you wont overboost with the SC.


I agree with Latinmax....
you must have an EGT


and I highly recommend fuel pressure gauge.
A/F makes a good fishing weight.
Old Sep 29, 2003 | 09:24 PM
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is this EGT(they call it a pyrometer) sufficient, i kinda wanna keep with the theme of my current gauges.

http://store.summitracing.com/defaul...&part=ATM-4344
Old Sep 29, 2003 | 09:45 PM
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Originally Posted by MaximaRider
is this EGT(they call it a pyrometer) sufficient, i kinda wanna keep with the theme of my current gauges.

http://store.summitracing.com/defaul...&part=ATM-4344
That would be a Yes. You will have to get a bong welded into your Y-pipe or buy a tap and tap a hole in your header for the probe. That will warn you of overheating, which is from running to lean and WILL cause detontaion.
Old Sep 29, 2003 | 09:51 PM
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thanks latin max, i was also wondering if this feul pressure gauge was sufficient, it only goes upto 100psi?

http://store.summitracing.com/defaul...4312&x=17&y=12


yes i know i have to buy the braided line seperately, its like $90


Also wondering where & how much 1 step colder plugs are. Thanx
Old Sep 29, 2003 | 09:55 PM
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Originally Posted by MaximaRider
thanks latin max, i was also wondering if this feul pressure gauge was sufficient, it only goes upto 100psi?

http://store.summitracing.com/defaul...4312&x=17&y=12


yes i know i have to buy the braided line seperately, its like $90
I would not do a mechanical FP gauge in the cab of your car (it is fine under the hood while tuning) but not in the car.
You have to do a electronic so that if you have a high pressure fuel line burst it is not in the car or on top of you. That would be ugly!!!!!!!!!!!
Old Sep 29, 2003 | 09:58 PM
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Originally Posted by LatinMax
I would not do a mechanical FP gauge in the cab of your car (it is fine under the hood while tuning) but not in the car.
You have to do a electronic so that if you have a high pressure fuel line burst it is not in the car or on top of you. That would be ugly!!!!!!!!!!!
ouch no thanx how bout this one...

http://store.summitracing.com/defaul...&part=atm-4363



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