LF97C5Vette

Hi All so i've been debating with myself the last couple days on what direction to take... here's my situation

I have a '97 LS1 C5 w/ 60k Miles and the following drivetrain Mods

DTE Supermaxx LT Headers, Hi Flow Cats & X-Pipe
B&B Bullet Cat Backs
Twin Cone K&N Air Intake

323rwhp 335rwtq Untuned

Now the debate is Cam vs. Gears.

The cam install includes:
TSP Comp 228R (228/228 .588/.588)
Texas Speed PRC dual springs/seats/Titanium retainers
Manley pushrods
LS2 timing chain
LS6 oil pump
GM gaskets(H20 pump, front cover, crank seal, oil pump oring)
Mobil 1
Dexcool coolant/distilled water

The Gear install includes
DTE 4.10 Stage 1 Diff from Tbyrne (Lots of details on diff in their site.)
2006 C6Z left output shaft
O.E. right output shaft
O.E. clutch pack

I already own a LS6 Intake Manifold and fully assembled LS6 Cylinder Heads. These will both be installed if I go Cam OR Gears.

Would folks reccomend the Cam in addition to the heads & intake, or the gears with Heads & Intake?

370ish HP w/ 4.10s vs. ~400hp w/ 3.42s

I think i'll be happy w/ the performance levels after either mod and will likely not do both, so please refrain from suggesting doing both cam & gears... hehe.

Parts and Labor either way will be around $2,000. So no big financial difference.

Thanks,

Dan

vince3

i would do a bigger cam.
i have the g5x1e (228/232) and i wish i would have gone bigger.
i also have 3.90 gears. I would pick the bigger cam.

Vince

oldschoolvette

what gear is in the car now?

chuckster

I'll make it easy for you....Gears!

The Gears are a muliplier... meaning the gain is there from 1rpm to Redline..

Assuming a relatively stock motor.. The 4.10's will pull the car like you added 75 more HP/TQ

If your cam can give you that sort of gain (Which I doubt) then its a Tough choice.. Also the CAM wont even be noticed under 2500rpm..

The gears are nuts....

fsuforever

go for both

jhong321

What will you be using your car for ? if all you care about is the 1/4 mile then gears would be the best bang for the buck. But if you like to race from a roll (50-60 mph) then the cam would help you more. The gears would hurt you on freeway pulls. (the other car will be 1 gear in front of you. ie your 4th will be = to his 3rd) And we all know 3rd will pull harder

Quaternion

I guess you realize that gears don't add any power to the car ... right? You will actually lose about 8rwhp, maybe more, with the gear swap, due to the increased viscous friction losses in the drivetrain. Many people have learned this the hard way on a dyno ... ahem.

It is true that you WILL actually feel an increase in acceleration in a given gear and rpm of exactly 4.10/2.73 = 1.5 = 50%. However, you have actually lost a little power in the process. Your gains in the 1/4 will come from a little better 60ft, and optimized 4th gear average power, due to increased trap rpm.

These are the advantages of the gears as I see it, from my short and non lustrous career as a drag racer Higher number / lower rear end gearing gives you:

1) The ability to easily turn over a set of racing slicks, for 2nd gear burnouts
2) Better acceleration off the line, if you're hooked
3) Believe it or not, I felt that I could actually rehook in the 60ft after a spin on launch with the 4.10's, vs. my stock 3.08's, since the tires were turning slower. It's as if I had more ... resolution .. I can't really describe it.
4) You can optimize your trap rpm, so that you're just over your peak hp. This allows you to maximize average hp, which is what it is all about during the 1/4 mile
5) It helps the driveability of bigger cams,that have lost a lot of part throttle torque from 800rpm to 1500rpm, which of course, the tuners never show you on their full throttle +3000rpm dyno plots ...
5) The feel in your back when you blip the throttle on the road in any gear, and the neck snap that results
6)Here's one most don't think of ... the gearing can help your car cruise at an rpm OVER a drone zone in your exhaust system (did on my Mustang in 5th)

The disadvantages of gears are:

1) You shift more
2) The car actually gets louder during daily driving, because you are at a higher rpm
3) You will stress your drivetrain more, if you're hooked on launch
4) You will lose top end in an all out race to top speed, unless you redo the 5th and 6th gears. Even with A LOT of torque from a blower, you probably won't make top speed in stock 6th (Most people will never see 175mph anyway, and don't care, but some do )

What I have learned from reaching the lunatic fringe of high performance, is that once you start down the slippery slope of car modifications, you really can't stop. If I were you, I would plan out my final desired NA car goal, and design it as a final system.

Based on your post, my guess is that you want both the gears and the cam. So I would do both, and find some way to pay for it. Have you thought of hocking your wifes diamond ring

AU N EGL

You have a 97 LS1 with 60,000 miles. That is a lot of miles to do heads and cam IMHO.

Would not a new LS6 or LS2 be a better choice, then add a bigger cam to one of these. May cost a bit more up front, but the power gains and relabilty will be far better then rebuilding an older engine.

nwdanner

Sorry, but I disagree. 60k miles is nothing to worry about based on what I've seen/read over the last 8 years. I know of many LS1s (y-body & f-body) which have had H/C installed with way more than 60k miles on the ODO and not one of them have encountered a related failure, even after hard abuse at the track. I'm sure there are a ton of owners of such vehicles on this forum.

My $0.02...

LF97C5Vette

The Stock MN6 Corvette comes with 3.42 Rear End.

My car is a daily driver. I don't really drag race, but I do enjoy plenty of spirited driving. I've been to a couple auto-x events as an amateur, and it was fun, but i'm not keeping that in mind while modding my car.

Yup - i'm aware of the potential HP loss from gears, but the increased mechanical advantage, and the obvious accell increase is whats important, not my final dyno numbers. (Although if i go H/C i would like to hit 400rwhp, but it's not deal breaker if i don't...)

And i'm not married - so no ring to hock...

Don't have that kind of money.



Dan

LF97C5Vette

Almost all my 'spirited pulls' are from a standstill. Ocassionally i'll down shift and get on it while goin 50-60 on the freeway...

I'm not sure i follow how it would hurt me on the freeway. I think i see what you mean - but will that actually affect me?

If you take my current C5 and race it against itself (except with the 4.10s) from different speeds, because of the different gearing there would be ideal speeds for one or the other to start from. For example:

At 60 MPH in 3rd gear.
3.42 = 3449 RPM
4.10 = 4135 RPM

So who has the advantage at 60? What about 40 and 70?

40 - 2nd
3.42 = 3149
4.10 3775

70 - 4th
3.42 = 3096
4.10 = 3711

At 6000 RPM the 1-5 Gears looks like:

3.42......4.10
51..........42
76..........63
104........87
135........113
183........152

So obviously because of the different gearing there will be better starting speeds. But from an over all ability to accellerate at any speed, i'd still say the 4.10s give a better more aggressive and usable gear box over the 3.42s.

For Daily a daily driver with lots of spirited runs - it sounds like the gears will make a more noticeabe, more commonly used increase in performance.


Dan

71'AirStrike

I am in the same boat as you.
There is a fork in the road ahead; Heads and cam to the Left and gear swap to the Right.

chad

AU N EGL

That is why I posted it. If there has been many many good reports of H&C on 50K plus motors then cool, go for it.

and yes 2 grand is a lot less then 6 grand

Good Luck with the project and keep us posted

The Wrench

When you come to a fork in the road..........take it.

Yogi

chuckster

Believe it or not, I felt that I could actually rehook in the 60ft after a spin on launch with the 4.10's, vs. my stock 3.08's, since the tires were turning slower. It's as if I had more ... resolution .. I can't really describe it.

You are correct.. Lot's of avid drag racers say the same thing.. the slower turning tires are easier to get back under control...


The disadvantages of gears are:

1) You shift more

No you don't have to.. Anyone who has 4.10's will tell you, light to light is a breeze going 1st, 3rd, 4th, or 1st 4th 5th....
Hitting every gear when not needed is not smart driving.. Ever see an unloaded Peterbilt pull away and use all their gears?

2) The car actually gets louder during daily driving, because you are at a higher rpm

Same here.. not using all the gears keeps the noise down.. sometimes I go 2nd to 4th...
3) You will stress your drivetrain more, if you're hooked on launch

Only the parts AFTER the differential are stressed.. (Axle, CV and Tires) the Clutch actually gets it easier...


4) You will lose top end in an all out race to top speed, unless you redo the 5th and 6th gears. Even with A LOT of torque from a blower, you probably won't make top speed in stock 6th (Most people will never see 175mph anyway, and don't care, but some do )

Not coompletely true... Most stock cars run out of HP before seeing Redline in 5th gear.. The 4.10s will allow the car to see Redline now.. Which give the car more gear and actually hit about the same top end but in a higher gear..

Gannet

Gears. The gains are instant, and everywhere, and have essentially no downsides, other than 6th-gear cruise mileage.

If you have an untouched 60k-mile longblock that is running well, I'd be inclined to do the gears and leave it alone, including the heads. Don't fix what ain't broke. You may well find that the gears alone give you all the acceleration you need or can use (those pesky street tires).

If you do end up doing the heads, I would do a cam at the same time. The additional expense is minimal and the gains are huge. Don't take the top end of a 60k mile engine down without freshening the whole thing: heads, valvetrain, oil pump, etc. But do the gears first. It impacts your cam selection.

LF97C5Vette

So it looks like folks are leaning towards the gears as much as I am. I think the gears are less likely to dissapoint, and i'll probably use their performance gains more frequently (ie. get my money's worth)

Maybe I will just do the gears for now, and wait a while before putting the LS6 heads on until i can CNC them and toss in a 228 cam too...


Dan

71'AirStrike

A local Car shop here in AZ (AZ power and sound) made the same statment. I feel its good sage advice.

So what would be a good cam to complment a 4.10 gear (and wider than stock tires)?


chad

LF97C5Vette

Why is it that a differential effects your cam choice?

What aspects of a cam compliment a differential?

So, for 4.10s would a cam with a 3000+ power band be better, or a cam with a 1500+ power band? (For example)

Seems to me that with 4.10s a cam that makes more power down low isn't really that important, because in lower RPMs the mechanical advantage the 4.10s provide will make up for a bigger cam's lack of low end power.

Am i looking at this correctly?



Dan

jhong321

I had the 4.10 in my car and was running about 450 rwhp when i raced my friend with 410 rwhp and 3.42 gears he would always pull on untill
5th gear because he was able to stay in gear longer and start one gear earlier.
I would suggest doing the heads and cam first and see how you like it.
if you look at alot of the high hp guys they will alway stay with the 3.42 or even lower because of the power that you will be putting out.
Just my 2 cents