Suggestions For Mods?
Instructor
Joined: Jan 2002
Posts: 150
Likes: 0
From: Springfield PA
Re: Suggestions For Mods? (Zankou77)
200-4R Overdrive Trans & 3:73:1 Rear Gears
I have been looking into this and contacted BTO and think this would be good mod for you in Cali with all the highways. Not sure what gears you have. If you have stock 3.08, then you are probably turning over 2500rpms @ 70mph on the highway. With the 200-4R and 3:73 gears you will drop 400+ rpms in 4th @ 70 and give you a 10.22 overall first gear ratio. From what I been told, ideal first gear ratio for street/strip is around 10.40. This would be a fun performance mod and give you better hwy gas milage and would cost under $2K for all the parts. Something I hope to do in the future.
[Modified by Steve81, 11:00 PM 8/27/2003]
I have been looking into this and contacted BTO and think this would be good mod for you in Cali with all the highways. Not sure what gears you have. If you have stock 3.08, then you are probably turning over 2500rpms @ 70mph on the highway. With the 200-4R and 3:73 gears you will drop 400+ rpms in 4th @ 70 and give you a 10.22 overall first gear ratio. From what I been told, ideal first gear ratio for street/strip is around 10.40. This would be a fun performance mod and give you better hwy gas milage and would cost under $2K for all the parts. Something I hope to do in the future.
[Modified by Steve81, 11:00 PM 8/27/2003]
Melting Slicks
Joined: Aug 2003
Posts: 3,416
Likes: 291
From: dayton oh
Re: Suggestions For Mods? (Zankou77)
Zankou - here's a painless way to add some more $ to your UPGRADE fund, stop wasting your $ on the 92 every time at the pump !!!!! Your 180hp stock motor will run just fine on reg unleaded, the low compression of your motor doesn't need the extra octane. Most of the major petro manufacturers openly admit virtually every auto will function well on basic unleaded-- even the ones recommending premium. Do a search, read the articles -- unless your running a hi compression monster or nitrous/boost, premium is more about status than performance in a stock engine.
Now let's talk about this performance problem, since you live in the P.R.Cali --emissions/inspections will haunt you. Never fear, you can beat them. If you don't have an AIR pump, bolt on headers (dynomax ceramix coated), free-flo cat, and better mufflers (anything other than stock). Again, make sure the stuff has a C.A.R.B. # COST=$500-1000 depending on mufflers
Now that you have it exhaling, let's talk inhale. Pick up a better intake manifold (Edelbrock Performer with EGR) and drop a K&N filter in. COST=$150-200
All of this you could do/have done in one weekend, all without tearing into the engine.
Give it the right-foot test :hurray:
Now let's talk about this performance problem, since you live in the P.R.Cali --emissions/inspections will haunt you. Never fear, you can beat them. If you don't have an AIR pump, bolt on headers (dynomax ceramix coated), free-flo cat, and better mufflers (anything other than stock). Again, make sure the stuff has a C.A.R.B. # COST=$500-1000 depending on mufflers
Now that you have it exhaling, let's talk inhale. Pick up a better intake manifold (Edelbrock Performer with EGR) and drop a K&N filter in. COST=$150-200
All of this you could do/have done in one weekend, all without tearing into the engine.
Give it the right-foot test :hurray:
Melting Slicks
Joined: Aug 2003
Posts: 3,416
Likes: 291
From: dayton oh
Re: Suggestions For Mods? (Zankou77)
Stands for Calif Air Resources Board, means part is "sanctioned" by the SmogNazis -- parts with a CARB # keep them off your back come inspection/emissions time
Melting Slicks
Joined: Oct 2002
Posts: 2,106
Likes: 0
Re: Suggestions For Mods? (Zankou77)
Its the California Air ___ ___________, its for passing emmisions testing and stuff, any aftermarket parts that you put on your engine have to be certified by this CARB because they do not polute(that much more than stock or very little)
* Did i get that right?
* Did i get that right?
Race Director
Joined: Jan 2003
Posts: 15,176
Likes: 88
From: State of Confusion
Re: Suggestions For Mods? (Fast81)
What he said :iagree: Yet, if the '81s have 2.72/2.87 gears, you'll be leaving a lot 'on the table' by not going to 'deeper' gears.
If the Corvette has 2.87s, a THM350-C (lock-up converter), and 27" tires (255/60R15 BFGs), you'll cruise @ 60 MPH @ 2150 RPM, but you'd have little bottom-end punch (short of dropping in a 454/502/etc.) with the 'tall' gearing.
Below, I've calculated cruise RPMs at 60 MPH with various available ratios, based-on the above data:
3.08:1-2280 RPM
3.31:1-2450 RPM
3.55:1-2625 RPM
3.73:1-2760 RPM
With the 3.08s, you'll be turning 6% more RPMs at any given MPH, but you'll also be multiplying your available torque to the rear tires, both NOW, and AFTER your mods, by the same 6%! (By comparison, the 3.31s figure-out to a 15% increase; the 3.55s are 23%, and the 3.73s a whopping 29%!!!)
Will deeper gears hurt your fuel-mileage? Around town, not much; in steady highway driving, without-a-doubt. Your 0-60 (and possible excursions to the drag-strip) times will drop like you can't imagine, and merging/passing in traffic will be easier, too.
In fact, 3.73:1 gears CAME in '77-'79 Z28s, from the factory (in 4-speed cars), with motors very similar to the L48/L81 motors.
If you put 3.73s in your Vette, and perform the 'Right-foot test', you BETTER be hangin' on!!!!! :steering:
If the Corvette has 2.87s, a THM350-C (lock-up converter), and 27" tires (255/60R15 BFGs), you'll cruise @ 60 MPH @ 2150 RPM, but you'd have little bottom-end punch (short of dropping in a 454/502/etc.) with the 'tall' gearing.
Below, I've calculated cruise RPMs at 60 MPH with various available ratios, based-on the above data:
3.08:1-2280 RPM
3.31:1-2450 RPM
3.55:1-2625 RPM
3.73:1-2760 RPM
With the 3.08s, you'll be turning 6% more RPMs at any given MPH, but you'll also be multiplying your available torque to the rear tires, both NOW, and AFTER your mods, by the same 6%! (By comparison, the 3.31s figure-out to a 15% increase; the 3.55s are 23%, and the 3.73s a whopping 29%!!!)
Will deeper gears hurt your fuel-mileage? Around town, not much; in steady highway driving, without-a-doubt. Your 0-60 (and possible excursions to the drag-strip) times will drop like you can't imagine, and merging/passing in traffic will be easier, too.
In fact, 3.73:1 gears CAME in '77-'79 Z28s, from the factory (in 4-speed cars), with motors very similar to the L48/L81 motors.
If you put 3.73s in your Vette, and perform the 'Right-foot test', you BETTER be hangin' on!!!!! :steering:
Melting Slicks
Joined: Aug 2003
Posts: 3,416
Likes: 291
From: dayton oh
Re: Suggestions For Mods? (Glensgages)
:iagree:
Now for part 2 - my previous post had you at ~$1200. Spend the rest of the $ on rear gears (installed by a shop) like Glen outlined. I'm running 3.54's myself (why not 3.73's......with my TCI 700R4 I have STRONG low end + I like 100+ interstate crusing occasionally without redlining)
If you have any $ leftover, buy new rear tires cuz you're gonna need em!!!!!!
Now for part 2 - my previous post had you at ~$1200. Spend the rest of the $ on rear gears (installed by a shop) like Glen outlined. I'm running 3.54's myself (why not 3.73's......with my TCI 700R4 I have STRONG low end + I like 100+ interstate crusing occasionally without redlining)
If you have any $ leftover, buy new rear tires cuz you're gonna need em!!!!!!
