Slicks

[1qk4dr]

I need more technical advice than the mustang forum I'm on has to offer. I have a 2003 Mustang Cobra. I found a good deal on 28-10-16 Hoosier Slicks. Well the factory tires are 25.82" and with my gear ratio I'd run out of gear in third at about 115-116mph with a 28" tall tire. This is what I trap into 4th during a quarter on the stock tires. From my knowledge it's best to end at the end of your redline/peak power. People don't think I make enough torque to overcome the size difference which is hard for me to believe and that these tires would not lower my ET's.

2.107' @12.5@114.46

442whp 462.46ft-lb of torque at 3900lbs.

Please let me know what you guys think.

4th gear I'd be ending at about 5066rpm with these and I end at about 5600on the factory tires
3rd I'd end right at redline with these Slicks at 6500rpm. 104mph is redline on my stock tires. My power starts to drop off at about 6000 rpm.

[BadAssPerformance]

2.1 60'? My white Dak did that running 14.70's...

Sounds like traction is your issue more than revving it out high end. The slicks, plus larger diameter will help the short time, but the diameter might hurt a bit if you lose power at the top of 3rd. What gear ratio is in that? from what you said, 26" slicks would be best.

[1qk4dr]

2.1 60'? My white Dak did that running 14.70's...

Sounds like traction is your issue more than revving it out high end. The slicks, plus larger diameter will help the short time, but the diameter might hurt a bit if you lose power at the top of 3rd. What gear ratio is in that? from what you said, 26" slicks would be best.

3.55:1 rear end. I have a 2.66 first gear. I get 51 mph out of first and the taller tires should put me around 56mph. I do have a traction issues if I was to leave the line hard and so I have to come off fairly soft. There was a guy running the same tires that day turning 11.1@135mph with 2.0 60' so I don't think it just me having the same issue with this brand of tire. (555R nitto)

The slicks have been used once and they are balanced/screw/mounted onto rims. I don't think I could get a better deal than 175-200 dollars. Anyway I know they'll fit my car since he owned the same kind of vehicle.

[BadAssPerformance]

On my Shadow... 24" tall radials spin in 3rd and 23" tall slicks hook from 5k. Any slicks will make you quicker, but the diameter will optimize your overall 1/4 mile time... That def sounds like a deal, i say give it a try. :thumb:

[1qk4dr]

On my Shadow... 24" tall radials spin in 3rd and 23" tall slicks hook from 5k. Any slicks will make you quicker, but the diameter will optimize your overall 1/4 mile time... That def sounds like a deal, i say give it a try. :thumb:

Thanks bud, He agreed on 175 so I think I'd pretty dumb not to buy these. Anyway I should be finishing in 3rd gear now so I won't loose any acceleration going into 4th.

[BadAssPerformance]

Cool, let us know how it works :thumb:

[ShelGame]

On a side note, I worked on the design team for that car at Roush. If you have any powertrain questions about it, just ask:thumb:

[1qk4dr]

On a side note, I worked on the design team for that car at Roush. If you have any powertrain questions about it, just ask:thumb:

First of all how did you get that job. Second is there any stories you wouldn't mind sharing.

I've been pretty pleased with the car. With the minor bolt ons I have so far it picked up a nice chuck of horsepower on 91oct though I'm pretty low in the 03/04 Mustang World. You guys did a very good job sorting what needed to be added(crank,pistons, T56 and ext). Do you have an opinion on what the limitation on the stock motor is? What way did you guys try to improve axle hop, this what typically kills half shafts in these cars.

[ShelGame]

Roush was only responsible for the engine itself. SVT Engineering did the trans, suspension, body, etc. Interestingly enough, the girl that was responsible for all of the bodywork sits 3 rows over from me at Nissan now. It really is a small world.

Anyway, I remember we got ~500hp out of with a Lightning S/C pulley, K&N intake, and a Bassani(?) exhaust. It was definitely restricted from the factory. We actually had to redice the power because SVT really wanted to advertise it at 390hp/390ftlb. It made an honest 400+hp before the calibrators de-tuned it (dump fuel and pull spark near max rpm). I think our 3 SAE engines averaged 393hp.

I designed the S/C drive, the cooling system, alternator mounting, etc. Funny one is the S/C pulley cover. All of the aftermarket ones with the Cobra on it are the one I originally designed. It was too expensive to put into production, so it went out with the slots instead. We made a handfull of the covers in stainless with the Cobra. SVT loved it but didn't want to spend the money. Now, I see them all over eBay.

[BadAssPerformance]

Cool story Rob :thumb:

[1qk4dr]

I know that John Coletti was upset about the first motor design. It was NA and did not perform the way he expected. Then the 4.6 was redesigned and modified to use the Eaton 112. Kewl that this happened because I became a MustangCobra fan once I saw just pullied cars turning 11's at a local drag strip.

I'm not sure what these motors are making at the crank but 365-380+whp stock is not uncommon on dynojets. Since the Z06 of the same year was pushing about 350-355whp people just thought that cobra was in the 415-425hp to crank stock. If you were only getting 393 at the crank then it must have a very efficient drive train??? Maybe it just the differences in the dynos???

Epcor here over in ohio makes the castings for the Eaton Superchargers and I got to visit this place this year for work related issues with parts that we have made not knowing that until I questioned why there was so many superchargers laying around,lol. It's kewl that I'm talking to the person now who developed some crutial pieces to the making of this car. You did well btw.

[ShelGame]

I know that John Coletti was upset about the first motor design. It was NA and did not perform the way he expected. Then the 4.6 was redesigned and modified to use the Eaton 112. Kewl that this happened because I became a MustangCobra fan once I saw just pullied cars turning 11's at a local drag strip.

I'm not sure what these motors are making at the crank but 365-380+whp stock is not uncommon on dynojets. Since the Z06 of the same year was pushing about 350-355whp people just thought that cobra was in the 415-425hp to crank stock. If you were only getting 393 at the crank then it must have a very efficient drive train??? Maybe it just the differences in the dynos???

Epcor here over in ohio makes the castings for the Eaton Superchargers and I got to visit this place this year for work related issues with parts that we have made not knowing that until I questioned why there was so many superchargers laying around,lol. It's kewl that I'm talking to the person now who developed some crutial pieces to the making of this car. You did well btw.

I dunno if he was upset so much. When I started, there were going to be 2 cars - the 'regular' Cobra and the 'Terminator' Cobra. The 'regular' Cobra was going to be NA with ~350hp. The 'Terminator' was the S/C car. There was even some talk of a live axle version of the 'regular' car for the drag race guys. For whatever reason, all versions of the NA car got dropped when we made 400hp with a test mule (using Roush Stage 3 parts and an off-the-shelf M112).

I remember reading stories about how we 'SVT' tested the aluminum block and it wouldn't hold up so we went with the iron block. The truth is, we built 3 dyno engines with the aluminum block - none of them ever got to run. John C. decided that, with the timing he wanted, iron was less risky for the program. If we had a problem with the aluminum block and had to switch, it would've been a setback and delayed the cars until the full 2004 model year.

From what I recall, there is actually 1 part on the '03 cars that says 'Terminator' on it. I think it's on the backside of the plastic stick-on fake side scoops. A lot of suppliers were confused because we all called the car 'Terminator'. They thought it was a different car from the Cobra.

[1qk4dr]

They just introduced the aluminator 4.6Liter cobra engine with alunimum block. It's actually a bit lighter than the stock Cobra motor.

Do you know anything about the head tick issue and coolant issue with the head? Personally knock on wood I've been luckly not to get this problem.

[1qk4dr]

From what I recall, there is actually 1 part on the '03 cars that says 'Terminator' on it. I think it's on the backside of the plastic stick-on fake side scoops. A lot of suppliers were confused because we all called the car 'Terminator'. They thought it was a different car from the Cobra.

I'll have to look again but I think there is Terminator molded into the inside of the rear bumper also. I swear I remember seeing it when I re-installing the exhaust. I'll have to check again.

[ShelGame]

They just introduced the aluminator 4.6Liter cobra engine with alunimum block. It's actually a bit lighter than the stock Cobra motor.

Do you know anything about the head tick issue and coolant issue with the head? Personally knock on wood I've been luckly not to get this problem.

Yeah, but I think that's a 100% new block. We were working with the 'old' NA ally Cobra block. The GT uses a 5.4 aluminum block, too, and it was 100% new.

The head tick issue was due to oil foaming. Cyl #8 (Rear, Right bank - I forgot the cylinder order)? I think that one was farthest away from the oil pump, and so tended to lose pressure at high RPM. The heads don't (er, didn't) drain oil back to the pan fast enough, and the chain drive for the cams tended to foam it up on the way back down to the pan. That's my recolection anyway. I wasn't involved with the heads or lubrication system directly.

I don't remember there being any cooling issues with the head. At least, not during development. The S/C Cobra had the best cooling system of any Mustang. So much so that the Mach 1 carried it over complete.

[1qk4dr]

Yeah, but I think that's a 100% new block. We were working with the 'old' NA ally Cobra block. The GT uses a 5.4 aluminum block, too, and it was 100% new.

The head tick issue was due to oil foaming. Cyl #8 (Rear, Right bank - I forgot the cylinder order)? I think that one was farthest away from the oil pump, and so tended to lose pressure at high RPM. The heads don't (er, didn't) drain oil back to the pan fast enough, and the chain drive for the cams tended to foam it up on the way back down to the pan. That's my recolection anyway. I wasn't involved with the heads or lubrication system directly.

I don't remember there being any cooling issues with the head. At least, not during development. The S/C Cobra had the best cooling system of any Mustang. So much so that the Mach 1 carried it over complete.

They made things like even cooling mods for the cobra that I guess flows coolant to the head in an even distribution. I'm not sure how well it works. I wasn't aware of any foaming issue. I know Ford made a revised set of heads due to the tick but as much as I know about that. I'm glad it has a good coolant system because if it wasn't for the vents in the hood I wouldn't know where else all the heat built up would go from the Heaton M112,lol.

I'm running a 2.8" upper pulley vs. 3.6" from stock. I'm pushing about 14psi through the motor now vs. 8.5 from stock. People have ported the blower to make additional 50-60 whp on the same boost. Though it seems as though 475whp-500whp is about the limits on stock injectors and fuel pump without modification. Then they have upgrades like whipples, KB superchargers, and Turbo kits to get ridiculous amounts of power out of stock blocks/built motors. Did you guys know that mostly everyone was going to modify the car before you built the motor and designed for it or just made it strong enough to be durable for everyday driving on stock power?

[Ondonti]

People push 800+ on stock shortblocks from what I have heard.

[1qk4dr]

People push 800+ on stock shortblocks from what I have heard.

http://www.musclemustangfastfords.com/features/mmfp_0801_twin_turbo_compound_boost_2003_mustang_c obra/index.html

Back in 2006 I remember a Precision Autosports north of me pushing a stock block DD 03 Cobra with turbo kit, upgraded Catback, and a clutch to 805whp on 93 and 905whp on 93 with spraying the intercooler w/nitrous. Kind of useless power because I can't see any streetable tires being useful since people have issues at 550-600whp.

[1qk4dr]

Yeah, but I think that's a 100% new block. We were working with the 'old' NA ally Cobra block. The GT uses a 5.4 aluminum block, too, and it was 100% new.

The head tick issue was due to oil foaming. Cyl #8 (Rear, Right bank - I forgot the cylinder order)? I think that one was farthest away from the oil pump, and so tended to lose pressure at high RPM. The heads don't (er, didn't) drain oil back to the pan fast enough, and the chain drive for the cams tended to foam it up on the way back down to the pan. That's my recolection anyway. I wasn't involved with the heads or lubrication system directly.

I don't remember there being any cooling issues with the head. At least, not during development. The S/C Cobra had the best cooling system of any Mustang. So much so that the Mach 1 carried it over complete.

Rob I have a some of more questions if you don't mind answering

If the heads don't drain the oil back to the pan fast enough, should guys forget about using the 5W 30 oil (since it's thicker) and just use what is recommended from Ford(5W-20)? Also a girl was responsible for the bodywork? What about that young guy with the Ford GT everyones saying was responsible for it? Was the body work a joint effort?

Lastly what do you do for Nissan?

[ShelGame]

Rob I have a some of more questions if you don't mind answering

If the heads don't drain the oil back to the pan fast enough, should guys forget about using the 5W 30 oil (since it's thicker) and just use what is recommended from Ford(5W-20)? Also a girl was responsible for the bodywork? What about that young guy with the Ford GT everyones saying was responsible for it? Was the body work a joint effort?

Lastly what do you do for Nissan?

She didn't 'design' it from a styling point of veiw. She was the engineer who did the design/release work. The styling is only the outside shape. Someone has to turn that shape into a part that can be manufactured and installed at the factory. Everything is a joint effort. I love how Ford always gives credit to a single guy.

For the GT, all of the engineering work was done at Roush. Body, chassis, engine. There were guys from Ford, Roush, Mayflower(? I think they were responsible for the body panel production) in our building.

I'd definitely run what is recommended. Why run thicker oil anyway?

[1qk4dr]

I'd definitely run what is recommended. Why run thicker oil anyway?

Many people have decided to run 5w-30 in their Cobras. I'm not sure why. I know that I did it once since Walmart did not sell 5 quart jugs of Mobile 1 in 5w-20(It's just cheeper to buy it that way,lol). I know that new cars have tighter tolerances and I guess from what you stated above that this may of been a poor decision to use thicker oil because of the oil foaming issue. Since Mobile 1 recommends that you use the factory spec oil due to fact it was tested provide adequate protection of critical engine parts.

[1qk4dr]

I finally ran some passes on my slicks. I can't say much for my reaction time today since I was more worried on where I launched the car at. I took it slow started with a 2.6XX 60' @12.8 and ended the day with a 11.9@118.3 with a 1.83 60' and 1.745 60' 11.9@117.1 which made made me pretty happy since I first didn't break anything, second ran my first 11. RT gave me little advice to drop the clutch instead of slipping it. This really worked my 60' down a lot though I probably could of gotten 1.6 or 1.5 if I dropped it at a higher rpm but I feared breaking something.

[turbovanman²]

Wow, good times on both accounts, congrats, :hail: :clap:

[Turbo3Iroc]

A 1.74 is a very good 60' especially on a heavy car (non L body). To get in the 1.6 or 1.5 you have to have some serious power and an auto. Dean's best 60' is a 1.6, not sure of a lot of other guys but he posts his in his sig.

What rpm were you dropping it at? I usually drop mine easily over 6k.

Either way your car is running very good!

[1qk4dr]

3500 rpm I was launching at to get a low 1.8 and 4250rpm to get the 1.745. Some people will run 6000-5000 rpm launches to get even better 60's but they also using upgraded axels and other components or maybe even replace their rears with a Straight axle.

The car weighs about 3880-3900 with me in it.

[turbovanman²]

The car weighs about 3880-3900 with me in it.


What the hell do you have in it? :wow1:

[Clay]

What the hell do you have in it? :wow1:

100% fat arse mustang!!!!!!!!!!!!! ;)

[turbovanman²]

100% fat arse mustang!!!!!!!!!!!!! ;)

Huh? :confused:

[Clay]

Simon........ you do realize we are talking about an 03 MUSTANG cobra here....... right?

[1qk4dr]

Yeah the car is heavy,lol. The car weighs about 3660 stock and I'm about 210. I weighed it one time with me in it and it was sitting right at 3900. I removed the 5lb jack that could of made the huge difference on dropping below 3900lbs,lol. These newer cars weigh so much. Heck the New Srt8 Challanger is about 4100lbs and the new Cobra Gt500 is 3900lbs.

Weight adders
The irs adds 175 lbs on top of straight axle, Supercharger adds weight, Huge wheels and ext. 2003 Mustang Gt weighs 3260 and some how Ford was able to add another 400lbs to Cobra,lol.

[Turbo3Iroc]

Ahh I thought you had a modded Spirit R/T.

[1qk4dr]

Ahh I thought you had a modded Spirit R/T.

Sorry, I assumed that's what you thought but I wasn't going to question it.

I wished my Spirit ran 11's.

[turbovanman²]

Simon........ you do realize we are talking about an 03 MUSTANG cobra here....... right?

Nope, doh!!!!!!!

[amoparacer]

I think your 60 foot is as good as you will get 1.75 is about it. My GLHS average is 1.80 I have run this car at least 100 passes much lighter than a spirit average is 1.8 and I drop the clutch at 6000 rpm no fear of breaking any thing. I have had the occational 1.67 but most always 1.74-1.82 great to see a spirit in the 11's hard to do.:clap::clap::clap:

[R/T]

He's talking about his MUSTANG COBRA, not his Spirit R/T... :p