'03 Mods & Expected Gains

[abailey269]

I will be purchasing a '03 cobra at the end of next month and have a number of questions. I have read all the threads in the '03 forum here and have already learned a lot, but have also come up with many new questions.

1. Pulley's:
I come from the land of turbochargers and all you do is turn a little knob and look at your boost gauge to see what boost level you have just risen to so all this "2.93, and 2.80 upper/3.10 lower" stuff is confusing me. I understand that different sized pulleys net different boost levels but dont know what each number will net on a boost gauge. What size is the stock pulley? Is there a list somewhere that has what pulley=what boost level? To add to the confusion cobragb said "A 6lb pulley with exhaust will net 440-460whp"---i thought the stock boost level was 8psi? Another question is how much boost can the stock SC produce before its un-efficient? How much boost could the stock internals handle daily? Is 18psi too much?

2. Exhaust:
I have read a lot here about the different exhaust systems that you recommend but one thing i didnt read is what size is optimal for this supercharged engine. On Turbocharged cars 3" is the size of choice, what is the best size for this supercharged motor? Also, what does "0/R" mean when talking about the basanni exhaust (or any if it applies)? I havent read anything about long tube headers, have I been around the Chevy guys too much or do you guys not use these? If you do, who makes a good set?

3. Intake:
Seems that a good ol 9" K&N filter will produce good gains, but is there an adaptor that i need to purchase to fit the cone filter? Or is AR's kit worth the extra money?

4. Chip:
I seem to be reading mixed opinions on when is the best time to get the chip. What would be correct/safest order to mod? i.e. Full exhaust, Intake, then Chip and pulley at the same time--what pulley could you use with the stock program, etc.

5. Suspension:
I havent seen anyone talk about suspension setups yet. What would be a nice setup for this car?

The '03 Cobra is the best deal for the money right now. Its potential is uncanny for the little amt of money that has to be invested. I just want to make sure i know the ins and outs before i start modding down the wrong path.

Thanks guys.

[ygohome]

Hi,

I'll try to answer some of your questions...

PULLEYS -

The stock size of the 03 CObra pulley is 3.65"

the 2.93 pulley is the same size as the one on the Lightning, therefore you will hear of people saying they have an 'L' pulley.

Go to the following website to learn more about the other different sizes of pulleys available and what boost gains they give

http://www.southfloridapulleyhq.com/...oducts_dub.htm

This is where I purchased mine from. You can also get the belt and larger idler pulleys from them if you like. the smaller belt is necessary... the larger idler pulleys are optional (i don't have them) and are meant to reduce belt slippage by increasing belt wrap on the smaller blower pulley.

The lower pulley that is mentioned is a crank pulley it basically does the same thing as the upper blower pulley by increasing boost. Except, it is larger than the stock crank pulley, whereas the 'L' pulley is smaller than the stock blower pulley.

The upper pulley is far less money and much easier to install... but you may get belt slippage (thats where the ilder pulleys come in).

The larger crank pulley is more money, harder/more time to install, but no slippage. But it also spins the assecories faster (the alternator for example).


EXHAUST-

o/r is short for Off-Road. This is an X-PIPE or H-PIPE without the catylatic converters. You can order the bassani x-pipe to come with the 'cats' and also with replacment straight pipes. This way you can easily remove the cats if you want to and later put them back on again.

QMP makes an excellent 3" full exhaust. My Bassani is great (only 2.5 ") for the performance level my car is currently at. I plan on going with the QMP soon though.

IMO, the kooks LTs are the best for the 03. LTs will give approx 30-40 additional rwhp for these supercharged engines. I'm holding off on getting them... my car is doing pretty well with the factory exhaust manifolds. Eventually I want to get them though.


INTAKE -

I have the AR 9" filter kit with plastic heat shield. The kit came with the filter, shield, adapter and thumb screws. It works great and I would recommend it. I don't know about the K&N.


CHIP -

I purchased the exhaust first and and ran with it for a long time before I ordered the pulley, belt, and NGK TR6 plugs (from SFPHQ). Then when it came time to install the pulley, I ordered the Diablo chip from Amazon Racing. Rick from Amazon programmed it for my mods and I put the pulley, belt, plugs, chip in all at the same time.

If you do not want to CHIP it yet, then go with a 3.2 pulley. Otherwise you may lean out the A/F mixture too much and cause detonation from too much air.

Regardless, get a dyno run with A/F measuerments performed immediatly after installing the pulley.


SUSPENSION -

I don't plan on changing the suspension except for stiffer bushings to try and reduce wheel hop. I've already scrapped the cats more than a few times over speed bumps. with LTs and a lowered suspension I'd just be asking for trouble.

Good luck to you

[97whitevert]

Thanks for the info!

[abailey269]

Originally posted by ygohome
Hi,

I'll try to answer some of your questions...

Good luck to you

ygohome, thanks a lot buddy. That cleared up most of the questions i had. I do have a question about your car for you:

Which upper pulley did you go with? (what psi are you running?)
Are you experiencing any belt slippage?

Would running 18psi daily have the supercharger out of its efficiency range--if not, what is it efficient till? Would this be too hard on the motor? I would think not with all the forged internals.

[ygohome]

I have the 2.93 Dial_Ur_Boost (DUB) pulley.

I am running 14-15 psi using this pulley and the other following mods:

Amazon Racing 9"filter kit
Bassani O/R x-pipe
Bassani 2.5" catback
NGK TR6 spark plugs gapped at .038
Diablo Delta Chip with two programs

one of the programs on the chip is for using 101+ octane racing gas only. The other program is milder and is for using 91 oct. It is the later that the car dynoed and produced the #s in my sig.

the plugs gapped at .038 was to reduce spark blowout that was happening in the higher RPMs at full throttle.

I also ordered the heavy duty pulley puller from www.pulleyboys.com made specifically for our cobra. AR and SFPHQ also make a puller tool.

18psi would be possible using a 2.93 upper and a 4# lower pulley.... or you could go with a 2.80 upper and a 6# lower and get around 19-20psi... but it will drop back down to 16psi after around 5500 or 6000 rpm because of the Eaton spinning past its 14000 RPM efficiency range and the hot air charge in the intake. But the low end tq and hp more than makes up for that drop.

my belt slips a little but I don't race often so it is not a huge concern for me. It is not audible. you can only tell by measuring the PSI and you can see it drop a little at the higher RPMs. A larger set of idler pulley is said to completely eliminate that slippage.

There is a new supercharger on the market. The KennBell "Blowzilla". It sells for $3600 and comes with aa programed chip, bunch of diff pulley sizes, boost a pump, boost a spark, etc... It can produce 25lbs using race gas (104 - 109 oct). You'd want to have your cats removed so the fuel doesn't burn them up. So the engine on these cars are more than capable. As long as they are tuned properly and are not too lean.

[Marlow]

http://www.alfageek.com/03faq.htm

[97whitevert]

cool-- lots of stuff there!!

[Marlow]

Yeah, I printed the .pdf version out and refer to it all the time.

[97whitevert]

would be a good idea....now, if i could just get the printer to work...

[abailey269]

Originally posted by ygohome
one of the programs on the chip is for using 101+ octane racing gas only. The other program is milder and is for using 91 oct. It is the later that the car dynoed and produced the #s in my sig.

So you activate to the race gas setting via a remote switch? Or do you have to pull the ecu back out?

Originally posted by ygohome
the plugs gapped at .038 was to reduce spark blowout that was happening in the higher RPMs at full throttle..

Very familiar with that. Its not uncommon to gap to .028 with high boost turbo charged applications.

Originally posted by ygohome
I also ordered the heavy duty pulley puller from www.pulleyboys.com made specifically for our cobra. AR and SFPHQ also make a puller tool..

They show just about any size upper pulley that one might want for only $80, why are these upper pulleys so much cheaper than other sites? Are they missing something vital? How is the quality?

Originally posted by ygohome
18psi would be possible using a 2.93 upper and a 4# lower pulley.... or you could go with a 2.80 upper and a 6# lower and get around 19-20psi... but it will drop back down to 16psi after around 5500 or 6000 rpm because of the Eaton spinning past its 14000 RPM efficiency range and the hot air charge in the intake. But the low end tq and hp more than makes up for that drop.

perfect, thats just the answer i was looking for. 19psi is safe on 93 octane (i live in atlanta), 20 is border line, 21 is asking for trouble. I would probably want to go with the 2.93upper and 4# lower to avoid any problems unless you know of guys using the later combo with out any problems. How much of a power difference (if you know) is there between the 19-20 falling off to 16psi and the 18psi setup?

Originally posted by ygohome
my belt slips a little but I don't race often so it is not a huge concern for me. It is not audible. you can only tell by measuring the PSI and you can see it drop a little at the higher RPMs. A larger set of idler pulley is said to completely eliminate that slippage.

Would it be safe to assume that the belt slippage would be much worst at a higher boost level, say 18psi, rather than the 14-15psi you are running? How much does it drop off, 1-2psi then pick back up or does it cause major power loss throughout the rpm band?

Originally posted by ygohome
There is a new supercharger on the market. The KennBell "Blowzilla". It sells for $3600 and comes with aa programed chip, bunch of diff pulley sizes, boost a pump, boost a spark, etc... It can produce 25lbs using race gas (104 - 109 oct). You'd want to have your cats removed so the fuel doesn't burn them up. So the engine on these cars are more than capable. As long as they are tuned properly and are not too lean.

From a review on the Kenn Bell supercharger kit:

"The meter, throttle body, cats, exhaust, manifolds etc. were all stock. 725HP is enough to make this vehicle run in the 9's at 135mph. Think about all that HP and performance for $3699. And there was more left. At 23 psi, this kit will make 657HP - guaranteed."

all I have to say is damn. Thanks for the insight.

[abailey269]

Originally posted by Marlow
http://www.alfageek.com/03faq.htm

Great site, added that to my favorites for quick reference.