Supercharger Tuning Question

MikeR351w · Jul 25, 2010

Hello, I have a 93 LX 5.0 with 125k on the motor. I currently have the following modifications:

-Vortech V-1 Supercharger w/9lb pulley
-Anderson FMS Power Pipe that goes into fenderwell
-80mm Mass air meter
-38lb Lucas Injectors
-255lph fuel pump
-NO FMU
-Edlebrock Performer RPM II Upper and Lower intake (ported)
-Stock heads - non ported
-65mm T/B
-BBK Headers, H-Pipe (No Cats) and mufflers
-Cobra Under-drive water pump pulley
-A/C delete
-200amp alternator

I know that is a lot of miles on the engine but it still runs great! I have yet to get it tuned and its currently at 16degrees timing. I have run it hard and have heard no detonation or pinging. I realize that is a lot of timing, so I rarely go past 4000rpm's.

I want to switch over to a 12lb pulley but I am wondering if that is way too much for it to handle. Probably, but I just want to be sure. I am planning on getting it dyno tuned this month, but dont have any clue what my A/F ratio is or how much boost I have. If I get it dyno tuned, I want to keep my setup and not switch pulleys afterwards.

Any clue how much HP I have? Is the 9lb perfect for this setup or can I go higher still? Dont want to blow the engine but my guess is it wont last that long if I up the boost...

PS- The car ran way better without the FMU

93fox5.0 · Jul 25, 2010

well first off get urself a aem wideband a/f guage that is very vital part of ur motor surviving with forced induction if ur running to lean ur f'd in the a, that being said the stock block has the average compression ratio for a FI car 9:1 im pretty sure it can hand 12 psi fine but i wuldnt push it much more past that if ur still running stock cams and heads i highly recommend a custom grind cam thru comp cams and a good set of heads u really make ALOT of power and feel a huge differance if u get that taken care of this is just IMO anyone else feel free to correct me if im wrong

MikeR351w · Jul 25, 2010

For a wideband A/F ration gauge, dont I need my o2' sensors hooked up? I dont have them anymore...

93fox5.0 · Jul 25, 2010

why wuldnt u have them? there no reason not to.... and i believe if i remember right the wideband sensor just screws into where the o2 sensor would go i think most ppl that have ther o2 sensors have another bung welded in to the pipe for the wideband but if u dont have them it shuld just screw into where the o2 sensors wuld of gone (assuming u just put an o2 plug where the sensor was supposed to be)

BYRDPE · Jul 25, 2010

MikeR351w said:
For a wideband A/F ration gauge, dont I need my o2' sensors hooked up? I dont have them anymore...

why aren't you running the factory o2's? you can either have a bung welded for the wbo2 or use the driver's side stock o2 location.

MikeR351w · Jul 25, 2010

I eliminated my smog pump and have a H-pipe with no Cats. Thats why... I do have the bung plugged up so I would then assume that the A/F gauge would come with a threaded insert to place it into the exhaust....

MikeR351w · Jul 25, 2010

MikeR351w · Jul 25, 2010

I have the following pulleys

2.95"
2.75"
3.15"

Which one? The 3.15???

93fox5.0 · Jul 25, 2010

not sure on size but yes a wideband has a basically looks just like an o2 sensor and screws right into where ur o2 sensor wuld be

MikeR351w · Jul 26, 2010

I currently have the 3.33" on now. Any suggestions on which one I should switch too????

fiveohwblow · Jul 26, 2010

Each size is said to change around 1-2 lbs, meaning I would switch to the 3.15 first as you will more than likely see 2 lbs, and then try the 2.95. I wouldnt suggest the 2.75 as there is more tendency for the belt to slip. Also, I would suggest taking the timing down to base of 10* as your tuner will demand/appreciate that and you dont want to pay for him to do it on dyno time. I would also suggest waiting to get on it until you get it tuned.

That being said, how do you know you have 9 lbs of boost when you dont spin it to its max/dont go above 4k rpm?

I know you will be fine with more boost WITH A PROFESSIONAL TUNE as I am running 13 lbs with my vortech, buddy is running 15 lbs with his turbo and neither of us have problems. I have 99k on my odo ATM.

BYRDPE · Jul 26, 2010

MikeR351w said:
I eliminated my smog pump and have a H-pipe with no Cats. Thats why... I do have the bung plugged up so I would then assume that the A/F gauge would come with a threaded insert to place it into the exhaust....

your smog equipment has nothing to do with your 02. go ahead and hook them back up.

MikeR351w · Jul 27, 2010

Thanks for the info FIVEOHBLOW. I will drop down to the 3.15 first and see if I get more boost. As I dont have $900 to spend on a PMS unit to tune it at home, I do want to put that on before I get it dyno'd. Also, I will drop the timing to 10deg before the dyno as well. I will also invest in a wide band o2 sensor and boost gauge too. I want to always be sure I am getting the right a/f ratio. How easy is it to swap out pulley's? Some forums say to remove the supercharger head unit in order to change the pulley. Seems to me that all I need is an impact gun and pulley tool...

Any guess on what kind of power I am making? How much boost will the 3.15" give me???

Kdubslugga · Jul 27, 2010

You do not have you HEAR detotnation for it to happen, I melted 2 pistons and never heard any detonation, but i sure as hell detonated ...... Put your timing back down to 10.. Trust me, the 5 horsepower you'll loose is well worth it.

Cobra912 · Jul 27, 2010

holy crap man get that thing tuned NOW! You want to run more boost but rarely turn more than 4000 rpm? seems pretty backwards to me. You don't know how much boost you're making now. That and you won't see any boost till your WOT. WOT under 4000?

A good tuner will tune it on the dyno and adjust your timing / fuel pressure. Feel free to change the pulley for the dyno if that is what you want, but don't be hammering on it till you get it tuned!I don't wanna see ya cook your motor!

Cobra912 · Jul 27, 2010

oh and you can change your pulley without removing the head unit from the car

CDQICKGT · Jul 27, 2010

MikeR351w said:
For a wideband A/F ration gauge, dont I need my o2' sensors hooked up? I dont have them anymore...

DUDE....hell yeah you need your o2's! unless your running a carb set-up. Without them how is your car going to know whether its running lean,rich or just right? I bet your not pinging cause your care is running in safe mode, pig rich and pulling tons of timming @ WOT. Any tuner should know this, and correct it ASAP. If you had 4 o2's you could delete the downstream 2 and the ecm would use the upstream 2. Im really suprised you dont have TONS of drivability problems. As for the wide band... you can either have a spare bung tapped in or take out 1 o2 and stick the wide band in for tuning puposes and return the o2 when your done tunning. Have checked for codes? I bet you have o2 codes unless your running mil eliminator. hope this helps some

MikeR351w · Jul 28, 2010

Ill get some o2 sensors and hook them up. I have no starting issues or driveability issues other than some bucking during decel when coasting to a stop without my foot on the brake. I have heard that this could be due to my engine running rich, which would then explain that problem... Ill swap the pulley to the 3.15 and then get it dyno'd. By not going past 4000rpms, I just meant that I dont like to beat on it yet because I have not had it tuned....

Mike in Texas · Jul 29, 2010

You are flirting with disaster if you don't have an timing retard and are running 16* at boost! At minimum get the wideband afr and a boost gauge before you put much boost on that engine. Dyno of course is best. Really no way to guess your hp but you should have plenty of fuel w the 38# injectors @ 9psi boost.

CDQICKGT · Jul 29, 2010

Mike in Texas said:
You are flirting with disaster if you don't have an timing retard and are running 16* at boost! At minimum get the wideband afr and a boost gauge before you put much boost on that engine. Dyno of course is best. Really no way to guess your hp but you should have plenty of fuel w the 38# injectors @ 9psi boost.

EXACTLY... your ecm uses the feed back from your o2's to adjust timing, and injector pulse to get optimum a/f.

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