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LTX and LSXPutting LT1s, LS1s, and their variants into Third Gens is becoming more popular. This board is for those who are doing and have done the swaps so they can discuss all of their technical aspects including repairs, swap info, and performance upgrades.
The next big item is getting everything to fit under the car.
My list of problems is as follows:
1. BMR Extreme torque arm is very large & does not fit between the driveshaft & floor at the front.
----- I started cutting the front crossmember & mount apart to get more clearance. I should have more pictures tomorrow.
2. Rear of torque arm was hitting the emergency brake cable bracket on the trans tunnel.
----- The rear mount has 2 sets of holes, but it will not slide towards the center as the ring gear area of the S60 rear interferes with the bracket.
----- After cutting some of the bracket it now fits.
3. Crossmember for the torque arm is too low & will definitely hit the ground.
----- I am currently cutting it into pieces to make it work. Nothing like spending $600 on something & chopping it up. Pics to follow.
4. Exhaust turned into a big project,but is working out pretty well. Pics to follow.
Due to the low ride height, the crossmember would be less than 3" off the ground.
I cut the crossmember in 3 pieces & proceeded to build a new version.
I wanted to make a passthrough for the exhaust & needed a 5" piece of tubing.
Unfortunately, I could only find a 4" piece of pipe, so I cut it & made it larger.
This is what I ended up with.
It is finally in place & now I'm trying to get some paint on it. I gained almost 2" of extra ground clearance.
I have not finalized it yet, but this is how the whole mess started....
The 4L80E is much larger than the factory trans, so it hit the floor on the right where the tail housing bolts on.
i wanted to move it to the right for driveshaft to torque arm clearance, but the trans hit the floor... the same with raising the rear of it.
This put the trans more centered in the tunnel, which put the torque arm very close to the driveshaft.
Initially I had 3+deg of tilt in the engine/trans.
After careful tweaking of the trans mount & dropping the front K-member down a bit (also for hood to supercharger clearance, which was originally 5/16"), I have it at approx. 2.5deg downward slope.
This all has a cascade effect on trans pan height. exhaust clearance etc.
The biggest issue with driveshaft angle is with the car lowered, the rear is further from the ground than the trans, meaning the driveshaft is going uphill towards the rear of the car.
If you match the rear & trans angle, the yokes are not pointing at each other.
With the T-56 I had the engine/trans almost level so this was not an issue, but it is more critical now.
I have a lot of adjustment capability & will do my best to find a balance between equal/minimized angles.
For more driveshaft clearance I modified the torque arm link.
The original bushings are approximately 5/16" thick, so I machined them down to .156" each.
Then I bored out the internal bushing from 1/2" to 5/8".
Then I threaded the 1 link for 5/8-18 & bored the other so I could weld the link directly to the bolt.
This allowed me to thread the 2 links together with only a few threads protruding & no bolt heads or nuts to take up space.
This added a lot of clearance on both sides for floor & driveshaft clearance.
Here is the final result... sorry the photos suck from all the glare.
I also could not resist painting the driveshaft to show off the machined ends. Even if you can barely see it in the car.
I had the UMI version of that BMR mid-length torque arm. Same basic design. Couldn't live with it and ended up cutting it out. It wasn't just the droop in the bar, the mounting tabs on the ends hit stuff too. It is right in the middle of the car... couldn't be a worse place for causing the car to hang up on things, especially when cresting the top of a slope.
I couldn't drive onto the alignment rack at the shop, couldn't get on my trailer, and I left my signature scored in the concrete of parking lot entrances. It was only a matter of time until I hit something that damages my unibody. It had to go.... brackets and all.
I had the UMI version of that BMR mid-length torque arm. Same basic design. Couldn't live with it and ended up cutting it out. It wasn't just the droop in the bar, the mounting tabs on the ends hit stuff too. It is right in the middle of the car... couldn't be a worse place for causing the car to hang up on things, especially when cresting the top of a slope.
I couldn't drive onto the alignment rack at the shop, couldn't get on my trailer, and I left my signature scored in the concrete of parking lot entrances. It was only a matter of time until I hit something that damages my unibody. It had to go.... brackets and all.
I agree with all these comments from my experience as well... I had the BMR version that is being used in this thread and had all those same problems with it in the end just as QwkTrip mentions... i ended up worrying all the time about hitting / scraping and potentially damaging the underside. I lived with it one summer then cut it out. I ended up going with a more traditional length UMI torque arm mated to the Holley LS swap type cross-member in my builds at this point
Do you either of you have any pics of the installed height of your crossmember?
I installed mine as high as possible.
The outer brackets hang down less than 3/4" the way I have it installed & could possibly grind some more off the lower triangle gussets.
My biggest concern is the right front pipe next to the trans pan. There was no good way to tuck it up any higher.
Life would have been much easier if I left the T-56 in it, but I figured getting the HP to the ground would have been nearly impossible.
After building two other supercharged manuals, I had to make a change.
I have even hit the V-band on the exhaust. Does not happen often, but has happened multiple times. I'm on my second V-band and it wears another dent as we speak.
I have had the mid-length torque arm as discussed. After that I made a longer torque arm to get back ground clearance and mounted it to a bridge placed across the forward parts of the Alston subframe connectors. The bridge is sandwiched between exhaust and driveline. The bridge also serves as chassis stiffener. I also use a 3" steel driveshaft to help with clearances. I don't have a good picture in my build thread so putting it here.
This spring I'm probably going to tear out that shackle torque arm. The car has always handled funny during hard braking and I think it is the shackle system causing the roll center to move, unloading the front tires. I'm thinking pretty hard about seeing if I can get one of those new Herb Adams decoupled arms to fit.
Yes, your crossmember was way lower than mine is... It appears your entire crossmember tube was below the subframe connectors.
That also helps to explain why my torque arm link is so close to the driveshaft as I'm an inch higher.
Hopefully you will have better luck with your set-up... one thing just to think about is that when you get on a road you aren't familiar with you can get into a situation where at speed you get into a dip and the suspension really compresses, this is where i would have the biggest scrapes to my bmr short torque arm cross-member as it came down pretty hard and then it drags until the suspension rebounds... as bad as that was the hump in the original bmr is pretty strong and resistant to bending... if you come down and hit on you pass through tube you might have some trouble
larger exhaust and cross members are pretty tough on these cars due to the original layout
I really do not like the Shackle type Front Mount.
One of the last designs that I used for the Torque-Arm in some Project Cars, used a "Closed-Tube" style Front-End Torque-Arm like shown below:
Then Use two Cylindrical Bushing Halves inside a piece of steel tubing for the Front Mount (slide front of Torque-Arm through Bushings):
Use a Tubular Cross-Member for the front Mount...
Notch both Ends of a 3" long piece of tubing to Weld the tubing of the Front-Mount to the tubing of the Cross-Member.
Should look something like the Image below (Cross-Member):
I did a few quick measurements today & it appears the V-band, the loop around the pipe & the gussets at the frame connectors are all within 1/4" of each other.
Time will tell...
As for the tubular slip yoke type arm design shown above, I'm not impressed with the long unsupported tube at the end...
After breaking the end off of one in my 95 Camaro, which ruined a nice aluminum driveshaft & ripped the rear brake hose in half at over 100mph... I'll stick with something more beefy.
I have an Unbalanced Engineering arm that I was originally going to use, but it would require an extensive rework to mount it in the tunnel.
I did not want to chop up something so hard to get.
After notching the 3" Vertical piece of Tubing it is only about 1" of full Tubing (not including the material that over-hangs and gets welded to the mating Tubing)...
That thing is NOT breaking!
(Unless your 0.1250" Wall Mild-Steel Welding is NOT up to the task)
With the Tube properly Notched on both Ends (this includes a significant 45-Degree Miter-Cut to the Wall of the Material from the Tubing Notcher).
The Design of the Joints are incredibly Strong (Thus they are used in Roll-Cage Design).
The Prototype that I tested in my own Third-Gen had a Half Inch Diameter Hardened Bolt going through that section of Tubing...
I quickly found out (after many Wheel-Stands) that the Bolt was not needed.
Also, you can always Triangulate the Mount to the Cross-Member if you are not confident in your own Welding.
I test fitted a set of 28 x 10.50 slicks under the car that I have for my S10 & of course the bump stops are against the tires with 6.5" BS wheels.
They are 18" wheels but still have the same dimensions.
I looked for the least intrusive place to remove the bump stops without removing more structure than necessary.
A few cuts & the inner structure is still intact.
I welded & ground the seams & put some fresh undercoat on everything.
There is no evidence of modifications.
Very clean work! looks great, what kind of undercoating do you use? Has that "factory" look that I would want to achieve (I was planning on using 3M rubberized)
But you really should have some type of Rear Axle Bump-Stops...
Universal Polly-Graphite Bump-Stops are easy enough to fabricate Mounts for in a Position further Inboard of the Original Locations.
How is the clearance front and back? IIRC, at 28" it gets a little tight.
Yes, it is very tight at the front corner near the control arm. I will be modifying that next & post some pictures.
Originally Posted by ughmas
Very clean work! looks great, what kind of undercoating do you use? Has that "factory" look that I would want to achieve (I was planning on using 3M rubberized)
I had issues with the 3M staying sticky.
Quite a few years back, I found a company called HUD. It looks nice & dries like bedliner, which can also be painted.
Look great!
But you really should have some type of Rear Axle Bump-Stops...
Universal Polly-Graphite Bump-Stops are easy enough to fabricate Mounts for in a Position further Inboard of the Original Locations.
Yes, I will be adding different bump stops.
I likely will make them adjustable so I can also retain a normal travel when using daily type tires.
Once my actual tires/wheels to arrive I will determine the allowable travel.
I'm looking into putting it inside the coil spring or inboard of the stock location.
As promised, here is a picture of the interference area. At full droop, the tread is against the inner fender.
I drew & made a small pie cut in the area behind the fender well.
After a few taps the gap was closed up & welded back together. Here is the clearance afterwards.
It still looks largely untouched.
I did get my tires in, but the wheels will be about 2 months until arrival.
They are 28x12.50 ET Street R's which are quite a bit larger than the 275/40's
As promised, here is a picture of the interference area. At full proop, the tread is against the inner fender
They are 28x12.50 ET Street R's which are quite a bit larger than the 275/40's
I can probably guess but why a radial and why 28"?
I'm shopping for slicks for this season and seeing as most of my dragstrip activity will be on test and tune Friday nights, track prep I suspect won't be ideal (although there is a glued "heavy hitters" lane). This is why I'm looking at the Hoosier QTP bias-ply DOT tire. The bias-ply, by most accounts, tends to be more adaptable to an unprepped and greasy track surface (especially with a limited suspension car such as my own).
I'm looking at 26" more because that's what I've always run and I have a good amount of data for comparisons.
Actually, that is a bias tire, not a radial. It will be more noticeable once it has air in it.
It is basically identical to a 28 x 10.50 slick.
Speaking with Mickey Thompson, it is closer in design to the stiff sidewall slick & also the same rubber compound as the slick.
I chose a 28's since I will be putting down a lot pf power & more sidewall really helps it stick.
I'll gladly waste a few HP turning a big tire over trying to baby it to get traction.
I have 2 reasons for theses tires...
First as you stated, it hooks better on unprepped tracks (& the street, where it will spend most of its time). but also for a secondary reason.
I also want to use the same tires/wheels on my S10, which has a manual trans... & manuals are not typically radial friendly.
The current mockup tires on the rear of the Firebird are 28 x 10.50-18 slicks I have for my S10.
I needed 18" wheels to clear the big C6 Vette brakes on it, but it does not hook on the street with the short sidewall, so I want to put it on 15's also.
I can then do double duty with 1 set of skinnies/sticky tires for both vehicles, since it turns into a small fortune for tires/wheels.
Actually, that is a bias tire, not a radial. It will be more noticeable once it has air in it.
It is basically identical to a 28 x 10.50 slick.
Speaking with Mickey Thompson, it is closer in design to the stiff sidewall slick & also the same rubber compound as the slick.
I have 2 reasons for theses tires...
First as you stated, it hooks better on unprepped tracks (& the street, where it will spend most of its time). but also for a secondary reason.
I also want to use the same tires/wheels on my S10, which has a manual trans... & manuals are not typically radial friendly.
The current mockup tires on the rear of the Firebird are 28 x 10.50-18 slicks for my S10.
I had 18" wheels to clear the big C6 Vette brakes on it, but it does not hook on the street with the short sidewall, so I want to put it on 15's also.
I can then do double duty with 1 set of skinnies/sticky tires for both vehicles, since it turns into a small fortune for tires/wheels.
Hmm.
The only reason I said radial (and it does look like a bias-ply reminiscent of my old ET Streets) was only because a quick internet search copying and pasting "28x12.50 ET Street R" comes up with: https://www.mickeythompsontires.com/...y-construction
with "R" standing for radial.
Beats me.
But I'm in the same boat wanting a bias ply slick although not for the stick shift as I'm running a 4L60.
The reason I'm interested in your tires choice is because the last I checked I couldn't get an M/T bias slick in a 16". And checking their website, that still holds true. Lots of 15's though. I'd thought about repurposing my 84 Z28's 15" rims for that reason. But Hoosier has a 16" bias slick option so that's the plan.
Yep. Nothing like a bias-ply slick on the street. I found freeway on and off ramps were very exciting!
EDIT: I'm not calling you out on your slicks or anything like that! Just wanted some clarification. Sometimes the internet does strange things.
I have it now.
Thanks again for your updates. There may a 28" tire in my future depending on how this new combination plays out. With a 3.06 1st gear and a 3.73 rear gear, it may need tempering somewhat.
I miss the old ET Streets. Great tire in my estimation. Still got them but at twenty plus years old and counting, I'd be a major risk at the track (but I still may try a quiet countryside burnout just to send them off!).
I have even hit the V-band on the exhaust. Does not happen often, but has happened multiple times. I'm on my second V-band and it wears another dent as we speak.
I worked on the shifter install, which turned out to be a bigger project than expected.
When you look into aftermarket shifters for a Firebird, they all say "not for factory console".
I figured I would do some experimenting since I have the manual cover that has a more generous opening than the auto does.
I did not want a race style shifter so I looked at the B&M hammer.
It is easy to use & offers both conventional & ratcheting abilities.
I mocked up a few spacers to get it positioned at the correct height as well as cut off some of the excess brackets that were in the way.
Afterwards, I put in a few nut-serts since getting a wrench above the trans is nearly impossible.
My next issue was the location of the shifter cable is right where the exhaust is.
The standard location of the cable & bracket is below the flange of the transmission pan, so I started building a bracket to raise the cable above the oil pan rail.
Of course, that changes the throw of the shifter arm so that also needs modified.
I finally got it all sorted out & it clears the exhaust nicely.
The console is all buttoned up with neutral safety & backup lights connected.
Now I have to find something to cover the gear pattern indicator.
For those that build cars, here is something that most can relate to...
A friend of mine calls it the "Rule of 5's"
For everything you change or modify, it seems to affect 5 other things.
Here is my latest...
I pulled the new wiring from under the console to the transmission.
That seemed to go decent other than the trans connector is huge & the floor hole is much smaller.
After de-pinning the connector, I managed to get the harness through the hole.
This is where the "Rule" comes into play.
I attempted to take the wiring from the console to the under-dash area where the Holley EFI computer is going to be mounted.
It should have been easy, but previously I installed a double DIN radio, which takes up a lot (basically all) of the space in the dash area.
With the trans wiring in place, the radio is about 3/8" from going back into position, so I will have to reroute some items under the dash to get everything in place.
Nothing is ever easy.
So, in order to feel a sense of accomplishment, I switched to the trans cooler lines.
I started looking for a nice line route & a good location for the trans cooler in front of the radiator.
But, in order to get the trans cooler installed, I realized I have to mount the chiller in the bumper first.
I really liked the results of a refrigerated intercooler, which uses the AC to cool the water for the supercharger.
Once again, I switched priorities.
Here is the chiller before I installed it.
I fit it into the front bumper support, since that was the only logical place I could mount it.
I forgot to take pictures of the brackets.
I will be plumbing it in the near future also, as it needs tee'd into the high & low pressure AC lines, along with mounting the pump & reservoir.
Finally, I could mount the trans & oil coolers.
They have been sitting here for a year now, so I'm also happy to get them off the floor.
Because of the trans brake, I chose coolers with thermostatically activated integral fans, that I can also manually override.
I put nut-serts & studs on the cooler flanges & mounted them to the edges of the radiator support & also to an additional cross brace in the center.
Because of the port locations, I ended up mounting the coolers on the opposite sides instead of trying to put sharp bends in the hoses.
It's amazing how fast the whole day is consumed.
I never liked the trans cooler lines along the block. I made AN lines from the trans to the passenger side frame rail. Then adapted to 5/16ths steel to the cooler at the front.
That said, do you have to deal with the fuel and brake lines on the driver's side where they get close to the headers? In and around the bell housing. I'm looking for the right heat shielding to slip over the lot of them. Maybe 2 or 3 feet.
My brake lines are still in the factory location, but I have new braided stainless -8 & -6 fuel lines installed in a foil covered fiberglass heat shield close to the factory location.
Unfortunately, the 2" tube headers are very close to the frame on the passenger side & I see no other good route unless I go over the trans & across the heater box.
I do not want the lines above the headers.
My brake lines are still in the factory location, but I have new braided stainless -8 & -6 fuel lines installed in a foil covered fiberglass heat shield close to the factory location.
Unfortunately, the 2" tube headers are very close to the frame on the passenger side & I see no other good route unless I go over the trans & across the heater box.
I do not want the lines above the headers.
Brake lines in the stock location here too. And the fuel 3/8" steel (OEM) plus a -6AN return. It all bunches up at the subframe turn near the firewall.
That sleeve looks slick. Economical too when compared to the DEI stuff. That 1-1/4" in the link would do all of the lines in that section nicely. Thanks.
Funny you should mention crossing the trans tunnel with the fuel lines. You may know that earlier carbed engines had the line cross over the tunnel right over the bellhousing. That landed on the PS frame rail and onto the mechanical fuel pump. I always thought that particular spot in the tunnel would get heat soaked when at the track. (It did). The EFI chassis that I have now has the lines along the DS frame and avoids the tunnel altogether. You have to rethink how to replumb a carbed SBC with that line arrangement though.
Thanks again. I'm going to get on to that heat shielding.
I made a little more progress today on the oil cooler lines.
A word of advice to anyone putting in a 4L80E.... connect the trans cooler lines first, before putting the transmission in.
You can get 1 fingertip on the fittings & with the aid of multiple stubby wrenches you can tighten them 1 flat at a time if you remove the mount & lower transmission a few inches.
It's almost as much fun as getting poked in the eye with a stick.
The dust on the floor looks terrible when the photos are taken so close up lol.
I also got the engine oil cooler lines installed.
They were not much easier than the transmission lines due to being behind the headers & a -10 line instead of -6 for the trans.
The routing to the front was not too bad considering the lines are not that flexible.
Up front the coolers are installed & plumbed. I still have some final touches & a few clamps to install but everything fit pretty well.
A word of advice to anyone putting in a 4L80E.... connect the trans cooler lines first, before putting the transmission in.
Even with a 4L60, getting to the lines after the install is a PITA. I was swapping transmission with such frequency (or so it seemed) that I fashioned a couple of short -6AN tails that stay attached. I swung those over onto the passenger side frame rail to a bulkhead style AN to tubing adapter and ran steel lines to the front. At least the adaptor fittings are easy to get to come removal/installation time. Again.
Your project is looking pretty good. There's nothing quite like a fresh build.
I made a little more progress today on the oil cooler lines.
A word of advice to anyone putting in a 4L80E.... connect the trans cooler lines first, before putting the transmission in.
You can get 1 fingertip on the fittings & with the aid of multiple stubby wrenches you can tighten them 1 flat at a time if you remove the mount & lower transmission a few inches.
It's almost as much fun as getting poked in the eye with a stick.
The dust on the floor looks terrible when the photos are taken so close up lol.
from my experience, I would suggest that you consider using more a weather pack connector vs those types of fast-on type connectors... wire terminals that don't support the conductor with a crimp on the insulation have a much higher likelihood of breaking over time in high vibration environments... also the terminal itself is usually much more fragile than the capability of a weatherpack etc type of terminal... the weatherpack connection is much more environmentally capable all the way around
for heat shielding another good option is Heatshield Products Hot Rod Sleeve
Good idea, I never really thought about it. That wire is for the trans brake so I just matched the connection it came with.
All other connectors in the car are weather pack style so I should be consistent.
12-28-2023, 10:12 PM
