Silver State Classic Challenge . . .

Ok first of all guys... he doesn't have stock gears in his T5 he has Gforce gears in it, so his final drive ratio is .75:1 unlike the TKO or the stock T5 gear ratio of .68:1...
Knowing this the gears in his transmission were designed more for racing and less for fuel economy...
http://www.maverick.to/mmb/showthread.php?t=75153

And why consider a T56? Not only is it bigger, heavier and more parasitic then even a TKO...145.00 LBS for the T56 in comparison too the TKO that weighs in at a hefty 119.0 lbs... really makes the 98.0 lbs.. of the 500 horsepower capable T5 he is currently running... look like a featherweight..

But usability wise he wouldn't really even be able to get past 5th gear... 6th gear is the same high/higher ratio then even the stock T5's... 5th gear is in the same range as his current gears of around .74:1 to .8:1 ratio.... And as for running with that transmission with the 4:11 gears in the rear end.. Well the T56 uses a similar ratio for the first 5 gears that the gforce gears have that he is running right now..

The Gforce ratios of 2.94, 1.94, 1.34, 1.00 and .75
Or the T56 ratios of 2.97, 2.10, 1.46, 1.00 and .74 and .50

So if he tried too run 4.11 gears he would nullify first gear and in turn make his 6 speed into a 5 speed with a granny low

 

First, I have no idea of what kind of HP/Torque the motor makes or tire size and without this I am are just guessing in the wind.
You know you can get a 2.68 first in the either the 500/600 or T56 and there are other gear sets available.
When you are road racing or on the 90 mile SSC you only use 1st gear and 2nd gear twice.............at the begining of the race and the end of the race, the gears you use the most are 3rd and 4th........and if you have the grunt, 5th gear.
So with that said, just a guess would say that if he used the 500/600 with 2.68 first gear and limited shifting to 4000rpm in all gears and if he could pull 5th gear (which he probably can't) he would be doing 140mph at 6100rpm with 26" Diameter tires and 4:11's.
So, if he used the same trans and changed to 3:55's he (again if he can pull 5th gear and maybe with this lower RPM he would have enough torque to do so) should be able to hit 140 in 5th at around 4100rpm, which in my humble opinion would be about perfect...............just a SWAG

 

here is my last dyno sheet

 

Thanks for the dyno sheet......................now with that said I believe you have the wrong cam for road racing. You have too wide a spread in peak torque and peak HP, the peak torque should be somewhere around 4200+rpm, not down in the 3400rpm range. If you could get the torque up to within 1000rpm range of peakHP I believe you could pull 5th gear and achieve the 140+ with a set of 3:55's and your current 5spd. I'm not saying this isn't a good all around street cam, it just isn't made for road racing or the SSC...................this is my opinion.
Now, with that said and after seeing the dyno specs it gets more complicated because of the cam............if you would run 3.23's or close to that you would be shifting at 5krpm in 1st, 2nd, and in third you would shift to 4th at over 90mph (5krpm)....................and as you shift into 5th you would be at your peak torque...............and from there the torque starts it's downward slide...............................so, just a couple of more questions, what size tires do you run and which gears did you use the most last year................did you mark your tach with peak HP and TQ so you knew where you were at.....................I guess since last year was your first year you had a lot more to think about than marking the tach......just
a thought.
Let me know,
John

 

just a quick over view of mo's motor and other tidbits.
the motor is a 331 with only 8.7-1 compression or close to that. it was built to be supercharged with a centrifugal blower. the cam came with his stroker kit and before he changed his mind to go blown.
the car has been used as his primary daily driver until recently when he purchased a smarter daily driver. so the car is more optimized for daily driving than open road racing. he may elect to change that now that he has a smarter daily driver.
hes rear tire height is 25.25" tall
he has access to any 9" gear ratio to be swapped into the rear end.
the g-force gears that we put into his t5 were the wide ratio set due to the anticpated supercharger. i dont have the exact ratios infront of me. i do know that he has a deep over drive ratio in it right now. that is why it has 4.10s in it.

 

Thanks Bryant, it all makes since now.
Almost always when making a dual purpose motor it's extremely difficult to "Have your cake and eat it too", that's why it's much easier to design and build a motor for single purpose....................it would be kind of impractical not to mention expensive to have one motor for open road racing and one the street.

 

not sure who it was.. but someone said earlier that.. "another way to go would be to swap your rear gears out just for this purpose to enable driving at max speeds in 4th gear. 2.70'ish with a lower rpm torque band would probably be just fine.. or 3.00'ish with a higher rpm setup should still send a 350 horse car to 150".

Sounds cheap and easy enough to do and fits that particular engines power band just fine IMO. Might not even hit 5 grand in 4th?

Plus.. you get to avoid 5th and all the variables, and debates, that come along with it. Personally.. if it were my ride?.. I'd just crank er' up to about 5,200rpm on the straights and let it fly the way it is.. to a bit over 140. But that's just me, I guess.

 

I agree with what you said about the 2.70's, and in 4th probably be just a hair under 5000rpm at 140...........and for sure the motor will be humming at 5000rpm for at least 13/14 miles while his is in the longest straightaway which is about 14 miles long...................that would be the utilmate test of for the bottom end/valve train. Although it's only 5/6 minutes......it seems like an eternity when you are at 140 just waiting for the read light to come on for the oil pressure switch/watching the water temp and trying to hold the gas steady................................been there, done that.......
kind of like running the motor you just put together on the engine dyno and running it up past 7000rpm for the first time.............all fingers and toes are crossed and you are nervous..............or at least that is the way I feel.
With the 2.70's he should do about 50mph in 1st, 75mph in 2nd, 110mph in 3rd and 140mph in 4th.......................he is going to be doing a lot of shifting and heavy braking with the 2.70's to keep it close to max TQ and for the most part whenever he down shifts it will be above max TQ...IMHO
Maybe what he needs to do is just put on the Supercharger/Turbocharger and stay with the same gears he raced last year.....................get a base line and go from their. Concentrate on the suspension/aerodynamics.
After all of this discussion..............at least in mine mind..............I feel has optimized his current configuration......motor/trans/tires/gears and needs to look elsewhere like aerodynamics/handling/braking..........IMHO

 

yeah.. no doubt the car will feel better all around with that SC and times will improve without even touching anything else.

and yeah.. I hear ya about pushing motors and mine hiney was puckered up tighter than a frogs arse when they put my 383 Blazers motor on the stand for the first time. lol

But I do know that it's often far less dramatic when you have one that is seasoned without ever having had any issues or debri in the oils. That one seems to be battle tested well enough by now to reduce the apprehension at least a little bit, IMO.

From there I would be looking at tire quality(speed ratings of at least Z would be mandatory).. braking integrity.. suspension integrity.. suspension performance.. and then finally braking performance. Some will put braking performance ahead in that list.. but running deep into a corner and scrubbing speed/time is usually of much less concern that flat out breaking something at speeds like this. One deficiency usually just kills time.. while the other can actually kill.. you.

 

You know, when you put a motor together with your own two hands and even though you check everthing 2/3/4 times...........when you put it on the dyno for the first time you are (it doesn't make any difference after I've done this a dozen times) or at least I am really excited and at the same time really nervous because you say to yourself, did I double check the tq on the rods...........did I get all of ring gaps the same and space them out, did I double check the main caps and especially the 4blt center caps and did they have the proper air gap................stuff like that........and you are just waiting for something to fly through the pan..............it never changes for me no mater how many times I've done it.

As for Mo's motor, I thought he had some issues with the motor.......but everything kind of blurrs together after awhile. Still, even with my Cobra which was a very well seasoned motor.............going down that 14 mile straight..................I was always a little nervous watching the gauges and trying to keep my eye on the road.

I thought Mo had Z rated tires from last year, I could be wrong.

As for scrubbing speed/time................coming down from 140+ to hit the apex of a blind curve.............unless you've got really good brakes.......well
as they say, "Racing can be hazardous to your health". And of course I would usually not start breathing until after I'd gone through "The Narrows" at speed (and I mean over 50mph)..............and just before The Narrows is a really nasty blind curve. It just depends on how good a driver you are (or brave) and how good your car is in the braking department. After racing SCCA road racing for a number of years I much prefer that (and consider it safer) than the SSC......................IMHO

 

I'm confident that the equipment I have in the car is high quality enough and installed with enough professional attention to safely get me through the Silver State Course. My only limiting factor should be my driving experience and capabilities. From what I gather so far it's best to stay in 4th gear. I have to talk to the guy who put together my short block and make sure I'm ok maintaining close to 5,000 rpm or just take the car to a dyno and testing it out in 5th gear and see if a temp probe shows the T5 overheating.

 

As long as you are confident that's all that counts.
I assume you are running synthetic oil in the trans now and would not see any reason why it should get hot unless it has some issues with bearings.
Have you ever thought about contacting CalClub at the California Speedway to take some driving lessons. I know me going to the SCCA 3 day drivers school helped me more than I can say...............and I still practice what I was taught.............................I believe you can even take the lessons in your own car.............which would be another big help as it show the limits of your current setup........................................just a thought.

 

That is a great idea! I have seen some ads but I think it would be really good practice. I'll contact them and keep you guys posted on that. Thanks for the advice.

 

you need to get the go pro vid camera. it would be great for the school and the racing.

 

yea I have to look into pricing. I think they are $300 or so if I'm not mistaken.