budget builder

iTrader: (3)

I know th w new engine is 150lbs+ lighter. I don't want a bunch of room between tire and femder. Does anyone know what I need to lookout out for or the best springs to use? Right now it's stock everything. 91 rs, had a v6 now a 350 going to 500hp ls3. W/6l90 & sfc's. And a 2500 stall

budget builder

iTrader: (3)

I forgot to add but I want to try to keep the stock height especially in the back I guess? The reason I say that it's because I would like to try to have true duals. I forgot to mention that I'm trying to do a big break upgrade on this car also if you all have any suggestions I would appreciate it

ShiftyCapone

iTrader: (7)

For brakes go to www.bigbrakeupgrade.com.

Your rear springs (stock or lowered) won't be affected by your new combo. As for the front, most lowering springs are fine, even with the lighter weight. I recommend weight jacks, so you can dial in the height exactly like you want.

Be careful with true duals unless you are dead set on them. For 500hp I would look into the hooker Blackheart 2.5 dual kit. A dual 3" is insanely expensive (I went this route) and not really needed for your power levels. A single 3.5 or 4" mufflex is a simpler and cheaper option in my opinion.

budget builder

iTrader: (3)

Be careful with true duals[QUOTEBe careful with true duals/QUOTE

Thkz for response. I don't want to sound like a rookie but I guess to lowering a car I am a rookie what do you mean be careful about the true duels. Although your idea about the single 3 in sounds a lot better than me anyway but what did you mean?

ShiftyCapone

iTrader: (7)

These cars were not designed for anything other than the tiny factory single exhaust. True duals take a lot of fab work to tuck underneath. You'll also have to run smaller bullet style mufflers which can often create horrible drone at steady state speeds. You'll also need to run a panhard bar relocation kit to give the exhaust room to transition over the rear axle. Lowering the car only confounds these issues.

budget builder

iTrader: (3)

Enough said no more needs to be said. I will not be doing the true doors. But a nice 3-inch into dual exit muffler & dual 3-in pipes coming out the back w/chrome tips does sound and will look good

ShiftyCapone

iTrader: (7)

You'll want a little bigger than single 3". I would look at Mufflex 3.5 and or their 4 inch single kits. A single 3" will choke down that LS3.

soloc4

The Hooker Blackheart 2.5” duel exhaust will be perfect for your application. You get everything that you want, dual exhaust, dual mufflers, dual stainless tips, and it all tucks up in the transmission tunnel. It will support your power level and the sound level will be tolerable. Like Shifty mentioned above, I have true dual 3” with bullet mufflers and my car is load, but I also have more than 600 hp, so I need the large exhaust. If it weren’t for the hp level, I would change out my exhaust for a more user friendly system because it is just unbearable on long drives. I also recommend weight jacks purely for the adjustability. You get the spring rate that you want and the ride height you desire.

budget builder

iTrader: (3)

Y'all are awesome thank you so much please keep the advice coming I'm planning on buying all my parts during the winter and then going for broke this spring with installing

ShiftyCapone

iTrader: (7)

I cannot parrot this enough. I'm at the point I'm ok with losing some power. The car is loud, which for the most part is tolerable. The drone at highway cruise is enough to make you go mad. I'm making changes this spring. I too am over 600hp and if I can't figure out new bullet style mufflers (heard borlas recently and they were way better) I will be going to single 4".

QwkTrip

iTrader: (22)

Confucius say: Man with 3" duals say nothing and seem wise, but really he not hear.

QwkTrip

iTrader: (22)

570 RWHP naturally aspirated with 3.5" single exhaust. No drone.

Instead of making yourself miserable with dual 3" exhaust, consider adding cubic inches instead. It will be a better driver.

budget builder

iTrader: (3)

I bought a ls376/480-495.
just wanted a good combo w/ 3.90 gears, 2500 stall, 6l90, 285/35r18 rear tires and 265/40r18 front. Carb intake and i already have the holley sniper good to 550hp. I will get proper ign and trans control. I want dakota digital cluster. This is not for race. I do not race. Just want something nice and fun. Thats why i didnt get the 525ls376

thatsupnow

Should throw the Sniper in the garbage and get a Terminator X max system that has 6l80/90 control

budget builder

iTrader: (3)

🤯 🤯🤯🤯🤯 seriously? Terminator x ???

thatsupnow

Yea the V3 update brought that support

budget builder

iTrader: (3)

I'll check into it

QwkTrip

iTrader: (22)

I don't know how easy / hard it is to work with, but Haltech is releasing a LS engine specific ECU. No pricing announced yet but rumor at LS1tech is around $1500.
https://www.haltech.com/news-events/...exus-rebel-ls/

budget builder

iTrader: (3)

Thank you for letting me know I thought we had to go with something like spear text Standalone harness so I don't know how much they charge for that special with the ECU and the TCU

budget builder

iTrader: (3)

I am not that tech Savvy maybe I missed the part about the transmission controller from haltech. I am very interested though. Very!!

budget builder

iTrader: (3)

And I hear you qwik.

I hear ya

QwkTrip

iTrader: (22)

No transmission support yet. Near the bottom of their page it says offerings will expand in 2024. Usually in these kind of situations 4L60E / 4L80E comes first. I'm not sure when or if they will get to the 6L90E ?

QwkTrip

iTrader: (22)

Regarding your initial question about suspension springs.... If you want stock height then you need to aim for a front spring that has an installed height around 11 inches with the weight of the vehicle on it.

I have a summary (from 3 years ago) of all the front springs Moog lists for Firebird. I don't have the list for Camaro but it's likely a lot of the same kind of thing. Posts #1583, 1584, https://www.thirdgen.org/forums/ltx-...ml#post6404837

What I saw is that Moog has about 5 different performance levels with approximate spring rate groupings of 300, 345, 420, 700, 750 lb/in. And each of those groups has offerings aligned with how much sprung weight is on the springs. That way cars equipped with different options (different sprung weight) can settle in to the same ride height.

Since your car is blown apart for the project anyway.... now is the time to get weights of unsprung components so you can do the calculations. And eventually you're going to have to measure the weight of the car to finish the calculations, but that won't be possible until everything is back together and the car is at full weight again.

Let me know if you need help with the math.

QwkTrip

iTrader: (22)

I might still have my hearing but I'm slow of mind. I just now got your joke.

budget builder

iTrader: (3)

Thx qwik and everyone

budget builder

iTrader: (3)

Ls376/480-495
6l90 w/upgraded torque converter 2.5-2.8k stall
3.90 limited slip
matching tranny x-member
Adjustable front coil springs
Long tubes with 3.5in collectors
Adjustable single 3.5in thru high flo cat to dual 3in magnaflow ss tips
c6 staggered 9in/10.5in chrome 5spoke wheels w/2in front spacers
Smoked headlight lenses, smoked talight lenses, smoked LED marker lights
flushed door handles
2in cowl hood
terminator x max system
Ls3 stock intake /injectors/throttle body/gas pedal/accessories
I want a Dakota digital dash.
Coribeau seats
(Exhaust size isnt set in stone, im willing to loose a little top end for comfort/quality/no hearing loss)
*** thinking of doing tubular k member***

If their are any conflicts that yall see please me comment. Help is appreciated I want to have a good game plan b4 ordering parts. A lot of small parts i already have. Do i have to do a BIG BRAKE CONV? Right now im running fourthgen ss 3.42 disk posi rear with prop valve spring upgrade. Brakes work very well. But do i need upgrade? Axles, stock or not?

kestell123

If you are using a 6L90 that has a 4 to 1 low gear I think that a 390 rear gear is way to much gear.

budget builder

iTrader: (3)

Well I guess I didn't think that out too good. Thx f9r the catch

budget builder

iTrader: (3)

How do I calc the best gear for a 6l90 vs 4l80

QwkTrip

iTrader: (22)

In application, did cars even use 1st gear of that 6-speed transmission or was it only trucks?
2nd gear is fairly close to 1st gear of the 4L80E.

HP Tuner software download is free, and although you cannot access an ECM free, you can look at a tune file for free. Maybe try to find a stock tune file for a car and open it up and see what gears are being used in the tune and under what condition does it skip 1st gear.

kestell123

Yes we use first gear. In my camaro I started with 273, I should have stayed there. I got greedy and when I went with the ford 8.8 and the 331's were to much. My Grand Sport Corvette has 273's and launches great ,it is at about 1250 rpm at 55mph. The base Corvettes use something like 255 gears and still launchs well.With proper tuning the 6L80/90 shift so fast there is no reason not to use first gear . It's not like trying to get out of first already at 10 miles an hour with a manual trans. If you want shift Manualy you can use paddles or just a momentary switch. There is no point in a 6 speed if you are only going to use 5. You just need to gear accordingly.You also have to consider what RPM your engine will at at highway speeds when you build your engine. A stock LS3 is happy running at 1200 RPM all day , a real loppy cam might not be.

kestell123

If I remember corectly Camaro SS [ 5th gen] used something like a 325 rear gear. AND remember to factor in tire size.

kestell123

If I remember corectly Camaro SS [ 5th gen] used something like a 325 rear gear.

budget builder

iTrader: (3)

INTERESTING!!! Anybody else want to weigh in. Trust and believe I am no expert. I am learning. I thought that a 3.90 with the 4.?? 1st gear would be earth shattering with a 28in tire. But I am no expert. Teach me

skinny z

You may find this calculator interesting.

http://www.wallaceracing.com/calc-gear-tire-rpm-mph.php

Tom 400 CFI

Most cars "like ours" (domestic/V8/~3000 lbs, etc) have a total combined gear ratio in first gear of ABOUT 9:1. That's first gear ratio times rear gear ratio, = ~9:1. I'd think for a performance application you'd want a little lower (numerically higher) ratio than that, so maybe look for a rear gear that puts you ~10-11:1, in first gear?

kestell123

With the 6L90 4.027 first gear a 2.73 rear gear results in a total gear reduction of 10.99 . With a 3.90 rear gear total would be 15.71. To put that into a perspective , if you were using a 4L80 with it's 2.48 first gear you would need a 6.33 rear gear to get the same total gear ratio of 15.71. Sound crazy now ,right?

QwkTrip

iTrader: (22)

According to the CTS-V owner manual, the transmission will start in 2nd when in D.

You might want to look more into what and why that transmission does in different cars, and when it's best to use first gear or skip it. That might affect your choice of gear ratio.

budget builder

iTrader: (3)

As of now I have a 350 with xe274h and a 700r4 with 3.42 gear and a 2k stall.

budget builder

iTrader: (3)

Wow, gotcha I think I'm starting to get it. Who in their right mind wants a 6 33 gear? By the time u rev itll be time to shift ten times. Hahahaha. I was thinking of cruising under 6th and not killing gas mileage.

skinny z

Fill in these blanks:
How fast do you cruise on the highway? As in MPH.
What is your tire diameter?
Which transmissions are you contemplating?

Tom 400 CFI

He's talking about using a 6L90E

• First gear: 4.027 to 1.
• Second gear: 2.364 to 1.
• Third gear: 1.532 to 1.
• Fourth gear: 1.152 to 1.
• Fifth gear: 0.852 to 1.
• Sixth gear: 0.667 to 1.

With ^that first and ^that 6th, he could probably go with something close to a 3:1 rear gear -maybe even a little higher (numerically lower) and end up with a pretty great range of ratios.

skinny z

Let's put that transmission in my car. Here's what I'd get.
I cruise at 75 MPH with a 26" tire and 3.73 rear gear. Lockup converter.
So the 6L90 6th gear would be 2410 RPM at 75. That's slightly better than my 700R4 with it's .7:1 O.D. as I cruise at about 2500.
But, my first gear (3.06) puts me at a combined 11.4:1. I read Super Stock guys that'll run a 4.56 gear with a 2.52 geared TH350 to get that kind of number. Hot street cars too. But with that 4.027 1st gear and my 3.73, you're looking at 15.02. Hardly needed (or usable).
So, to get my 11.4:1 combined 1st gear/rear gear ( because I know it works) it puts the rear gear at 2.83. Seems to be the general consensus here too.
Now you have a decent combined 1st gear plus the benefit of almost idling down the highway at 1830 RPM.

There you go.

skinny z

Let's put that transmission in my car. Here's what I'd get.
I cruise at 75 MPH with a 26" tire and 3.73 rear gear. Lockup converter.
So the 6L90 6th gear would be 2410 RPM at 75. That's slightly better than my 700R4 with it's .7:1 O.D. as I cruise at about 2500.
But, my first gear (3.06) puts me at a combined 11.4:1. I read Super Stock guys that'll run a 4.56 gear with a 2.52 geared TH350 to get that kind of number. Hot street cars too. But with that 4.027 1st gear and my 3.73, you're looking at 15.02. Hardly needed (or usable).
So, to get my 11.4:1 combined 1st gear/rear gear ( because I know it works) it puts the rear gear at 2.83. Seems to be the general consensus here too.
Now you have a decent combined 1st gear plus the benefit of almost idling down the highway at 1830 RPM.

There you go.

Tom 400 CFI

Yep. There abouts is the ticket.

budget builder

iTrader: (3)

80mph highway speed
27-28"
6l90
No racing, just want to sit my wife back whenever I feel like challenging her to reach for the $100 bill on the dash. And I don't know the cruise threshold of an ls3. Bbc's don't like to cruise over 3k for a long time

QwkTrip

iTrader: (22)

I have the Ford 6R80 with near identical gear ratios, 3.73 axle and 32 inch tire. Cruises around 2000 RPM at 70 mph. That equates to about 3.26 axle with 28 inch tire. Still very pedestrian. It could easily use more than that and not be a problem.

skinny z

80 MPH. .667 6th gear.
28" tire, 2000 RPM requires a 3.18 rear gear. 1800, 2.81.
27" tire at 2000 is 3.01. 1800, 2.71.

Depending on your preference of cruise RPM, you can mess with the overall 1st gear ratio. Keep in mind, that whatever you pick, with street tires, you'll be traction limited.

http://www.wallaceracing.com/calc-gear-tire-rpm-mph.php

budget builder

iTrader: (3)

Hey skinny, or anyone else who wants to chime in. Like I said b4 I have a 3 42 with 700r. So that's (3.42x3.06= 10.5) I was just looking for more off the line. (3.90x4.027=15.??) But I think I understand what you are saying. Since I do not race, I guess there's no use in gearing for a first gear drag race knowing that I'm going to be driving it on the highway at 70 80 mph and still don't want it screaming at 4,000 RPM. I do have a question or perhaps a couple of them. What speed because generally I guess you're shifting in the second gear at about what 2k-2300 RPM so how fast would I be having a shift into second from first if I did go with or at least stay with the (342x4.027=13.77) gear I have now? Wait a minute I guess that's the purpose of having that chart you sent me. My next question is I bought or purchased an LS 376/480 & will be going with the Terminator X Max I was wondering how this would affect me having about a 22 to 2.5k stall so I can stay in my power band longer? most days I will not be out on the highway cruising.

budget builder

iTrader: (3)

3.42x4.027=13.77
3.90x4.027=15.71
What if I just keep the gear I have? That saves me some $$$. 27in street tires. 6l90 normally shifts 1-2 @ ???rpm... at what speed? I figured a 2200-2500 stall, ( I think I need one with ls376/480) or do I just need to go with a 4l80 w/th 3.90 and be done???

I do like the way my 2500 silverado pulls with 4:10gears and 4l80 with just a 300hp 6.0 small cam. But it also weighs over 5k lbs. So I guess my 3400lbs car don't need that much gear ? Or tranny? Or, heck fellas i dont know. This is the science of the stuff and yes it confuses me. But thx to everyone helping me.