todd03blown

Thanks Scott for the info. That is moving out for a "mail" order tune!!

ShowCar

4,500-5,200rpm is what I think these cars need to see a good time like yours. My car w/driver is 3,800lbs and a full tank. What are your thoughts on these clutches and trannies in the new 5.0? Im heading to the track tonight for a few runs myself. We have good air today.

Long Stroke

I've heard my friends (other vendors) smoking clutches on the first couple trips to the track. Personally I feel when you over gear the car and over tire it that will happen. Our car only has 3.73's and we are running small 275/40/17 Nittos.

Also I like to COOL the clutch down after a pass. The whole return road I usually get up to speed and kick the clutch in and leave it on the floor. This dis-engage's the clutch and gets some heat out of it. Doe's it help, IDK, LOL.

As far as the trannys, I'm shocked! I was under the impression like others, that since it's used in the V6 and the V8 that there would be some durability issues. Max torque rating is what the 5.0 comes with from the factory. But so far they seem to be holding up very well. Although ours has gotten a bit louder with miles.

Scott

MattN03

Any concerns of running it to 7600?

Driver72

Two of a few reasons I got the 3.55's instead of 3.73's

1. Able to launch harder with less wheel spin
2. Able to hold 4th through 1/4 when stock and even when lightly modded (7000 rpms in 4th with 3.55's is roughly 117-118 mph. So I wouldn't need to take it so far into redline and have such a drop in power to because of it.

Ltngdrvr

Yeah, but he was also running the short 275/40/17's, way shorter than stock.

GRABOID

Hey he's got the steeda hood on also that's good for at least 20hp lol. Glad to hear that tri axe is on the way, but I was going to order the hood..... I can't get both!!!

PacManiacs

Great run! You've also done a wonderful job capturing the footage both in-car and from the hood.

ShowCar

I went last night to GLD and ran 13.4-13.6 at 108-110 all night long and stayed in 4th gear every run with 3.73's and street tires. The car is stock too. The 3.73 seems perfect for the track. Scott your driving skills really help with the good times.

Driver72

That's because you are at a track or a DA that only trapped 108-110 mph
That allows you to stay in 4th.
At a track with a great DA that will allow a stock car to trap at 112+ mph you are a few hundred rpms into redline or you need to shift to 5th.
Remember you will actually be going about 2+ mph faster than what your trap speed indicates when you actually cross the 1/4 stripe.
And also remember you are on a stock car.

3.73's are good for about 111.5-112 mph in 4th (or traps of about 110+ mph).
Put just an intake and tune on your stock car and even at your track you are into 5th.
3.55's are good for 119 mph stock (or roughly 117 mph traps).
Good for staying in 4th with quite a few mods.
Even with the OP's shorter tires on, he probably would of been able to cross the line in 4th at around 7200 rpms (instead of 7600).

Long Stroke

Thanks again everyone and very kind words PacManiacs and ShowCar.

I'll agree that the 3.73's seem perfect with the Stock height tires if you want to keep the car in 4th. Not sure why Nitto doesn't make a 275/45/17, that would be hot. Otherwise I still feel for best ET a 4.30 gear would prolly be best. When we switched from the 3.31 to the 3.73's with the stock 7300 red line, even with the extra shift into 5th, I picked up a solid tenth. It went from a 12.23 to a 12.13. Remember that 5th is a 1.1 in this car, and one of the reasons you really need to give it RPM to get this car out of the hole. Even with the 3.73s and a 1.72 short time the car seems to bog a bit, but it doesn't. It's still the lack of gear IMO.

ShowCar

Driver72 what are you running at the track with your 5.0?

Driver72

I'd say that's about right going from 3.31's to 3.73's
The 3.31's are a bit too tall and you lose too much in gear acceleration to compensate for not needing to shift.
The 3.31's will be a great ratio for the 625 hp supercharged versions as the huge power will more than compensate for the tall gearing. 625 hp with 3.73's would just mean spin city in the first 3 gears.

I think you mean raised to 7300 rpms correct? Stock redline is really 6800 rpms and rev limiter is 7000 rpms.


As I've said before, you'd still see that same tenth drop going from 3.31's to 3.55's.
The 3.73 gears will allow for slightly stronger in gear acceleration over the 3.55's but what you lose is the traction at launch and the need to go into 5th.
Those two things even out the 3.55's slightly less in gear acceleration compared to the 3.73's. That's why I feel the times of a stock 3.55 and 3.73 car would be the same (or slightly favor the 3.55's due to that need of a shift to 5th on the 3.73s) on a good track with a sea level or below DA.

But where the 3.55's I feel will have the advantage is when power is added.
It can stay in 4th longer and allow slightly hard launches with less wheel spin. That means less time consuming shifts and being in a better rpm range for power.
You add 50 hp to the 5.0 and as you saw you needed 7600 rpms to stay in 4th with the short tires. Even without the short tires you'd probably still needed 7200 rpms with the 3.73's
That means on the 3.55's you'd of been around 6900 rpms.
On these motors you are making more power at 6900 rpms than you are at 7200+ rpms.
Now add another 20 hp with an exhaust or race gas tune.
You need 5th on 3.73's even with the raised redline to 7300 rpms.
On the 3.55 car you are still in 4th but instead of 6900 rpms, you'll probably be in the 7200 rpm range.

My car is still to new to know but I'm gonna run some tests in the near future to test the gear theory and see.

In any case, your times were awesome for the mods you have.
It's interesting though that in the video it so seems you bog a split second after the launch, but hey you were driving, if you said it didn't then it didn't.
Did you get any wheel spin at all?

t-ray

Your ET is all in your launch. 108mph is good for deep 12's.

GRABOID

"I'd say that's about right going from 3.31's to 3.73's
The 3.31's are a bit too tall and you lose too much in gear acceleration to compensate for not needing to shift.
The 3.31's will be a great ratio for the 625 hp supercharged versions as the huge power will more than compensate for the tall gearing. 625 hp with 3.73's would just mean spin city in the first 3 gears."


If you try to run it on stock tires . Slicks will be able to hold that on launch. You should be able to get drag radials to hold it but not at a 5500 rpm launch.

Long Stroke

It would depend on the rear tire. Mine is shorter then stock so thats why I needed 7600 to get through the traps at 115.18mph. With a 27-28 tire you should be okay with the 7300, it would be close.

Your 100% right with as power goes up and tire size is maintained that a lower gear ratio is needed. I picked up 3mph in the 1/4 and 5mph in the back half in my 8 second street car switching from 3.73's to a 3.31 gear. Was able to torque the motor through the 1/4 better.

I say it didn't "bog" because any more RPM promoted tire spin. I went the 11.96 with a 1.72 short on Nittos and any more RPM on the launch resulted in tire spin and a 12.04 and 12.03. But I'm also not saying that a bit more slippage with the clutch might not of eliminated that bog and produced even a better short time. Street radials and a manual as I'm sure you know takes alot of pratice to get out of the hole. It's just a little more gearing IMO would help the launch, but at this point it would require 5th. And if thats case I say f-it and go 4.30's or 4.56's. Cause my 1st time with the 3.73's and 7300rpms I was barking 5th gear. I really don't mind the extra shift.

I've got a good Excel spread sheet on gear ratios and tire sizes and the affect on RPM and MPH if you would like me to email it.

But your right on. Lots of good info here.

Scott

SteedaGus

Correct, this is an old Mustang drag race trick.

SteedaGus

No, that is our normal pump gas mail order tune (the 93octane version) except the rev limiter was raised to 7600, we normally set it to 7300.

Driver72

I agree, good info Scott.
I possibly have the same gear ratio spread sheet. Somebody posted it a couple months ago, I downloaded it but have never really looked at it.

Doesn't surprise me you picked up so much time with your 8 second car going from 3.73's to 3.31's. As I stated and you know with big power taller gears are better.

Again, the reason I went with 3.55's is I didn't like the fact that on a "fast" track even a stock GT needs 5th to get a 112 mph trap.
But mainly because I knew I'd be doing at least some minor to moderate power mods (intake, tune, axleback) and with that the 3.55's will still get to the 1/4 in the top of 4th. And if I do supercharge the car, the 3.55's will surely be a better ratio than the 3.73's for getting the power down without spinning too much....but 3.31's would be best with the s/c
I'm not a drag radial kind of guy. I like running on street tires.
I like to know what I can do as I drive the car every day.
And like you said, it takes a lot more practice launching the car well with street tires, especially as you increase power.

I was going to suggest the next time you go, try slipping the clutch a bit more to see if you can eliminate what looks like a bog. I don't disagree I'm sure you probably launched as hard as you could without spinning.

Clearly you did a great job to get high 11's and over 115 mph traps on a intake, tune and tires only 6MT car.

I want to find someone near me with a 3.73 6MT car and do some acceleration testing to see which gear ratio is more advantageous.
But to be honest the 3.55's and 3.73's are very close anyway.
The 3.73's will have that slight "in gear acceleration" advantage, but the 3.55's will have the stay in the lower gears longer and less wheel spin advantage....so it may end up all being a wash anyway.

Driver72

haven't gone yet.
Just got the car about 9 days ago.
Has only 365 miles on it as we speak.
I've just been concentrating on the mods right now.

Did the wheels and tires thing 30 minutes after I bought it.
Then Clear Bra went on
Then Tinted windows and a few other minor things.
The FRPP 1" drop springs, panhard bar and axleback go on in the next 2 weeks.

Gotta get some free time off work to get that done.
I also gotta get a baseline dyno done soon too. Want to do it before the axleback goes on. Problem is, I won't have as many break in miles on the car as I'd really hoped for at that point.

Then after that CAI and tune.

Hope to get some strip time in the near future as well.