rsz288

Hi All,

This is a great forum, very informative with some real world knowledge being shared. The information shared on here is really deep and has been inspirational. Dont know how we ever did things before the net.

Time to share our experiences with getting a 6L90E trans into an early Camaro. Thought there may be a few out there that might be a little interested!

Decided to shelve the BBC and go for an LSX conversion with a 4L60/65. The A6 was most attractive but it seemed out of reach....unknown and expensive.

Was looking at 4L65 & 6L Gen IV requirements when John Spears wrote up the LS2/6L80 conversion in his truck. This sparked my interest no end and clearly the "unknown" went away. Hooked in a heartbeat. Then it was just a matter of making a decision.

To cut a long story short, a 6L90E was secured and we started to take the plunge. No one had done a 6L80 or 6L90 into a Gen1 or Gen2 Camaro etc. It seemed this was going to be the first. To make it worse we are in the land down under. A long way from mainstream help. After the trans arrived, the saw the story of the 6L80 into the 66 GTO on V8TV popped up with the GTO tunnel even challenged to fit a 4L65E. :ek:

The 6L90E has now been in and out for trial fits, and it mostly fits, with some slight tunnel revisions needed. The tunnel was a tough call, but it is a plane jane Camaro. No numbers match. It had a 73 454 & TH400. It ran well, but it was either the rat motor or an LSX...LSX won. Bad Penny and other conversions on here (67RSCamaroVette/67RSSS), Pro-Touring/Lateral-G (Scott's LS7) and others were the inspiration for the LSX.

The Gen IV motor has evolved to an LS7 wet sump now. Started out as a 6L L76/L98 (LS2 with L92/LS3 heads). We all know how the scope creeps on projects right. The John Spears write up on the 6L90 has been very helpful and he is clearly on top of things with this setup.

Here are some photos for now to give the forum members an idea. Its a BIG trans. That said, it is both tighter and looser than a 4L65. More on that later....the pix:

Comparison from rear....


Comparison from above....


6L90E mounted on the subrame for trial fitting...


Clearance at firewall...really no different from this angle than a 4L65. The bell housing is very similar. Convertor is the same size....


View from the diff up the trans tunnel....it sits higher than this when it is in the optimum position...


Tunnel modification....large section out....the trans is pushed up a little higher than it will eventually sit, so it appears to really fill up the section that has been taken out...


Looking down the trans toward the motor from inside the car with the tunnel section taken out...


Side view...it can be seen that the forward section of the trans is where most of the clearance is required...


It is a very tall trans. While it is possible to install it without cutting the tunnel, the height has the pan too close to the ground. It needs to be raised to get ground clearance. The good thing is that the drive shaft angles are looking like they will work too.

Pan clearance is still a problem. The 6L90 is a truck trans and it has a high capacity pan that hangs ~3.3" below the pan rail. It will need to be revised. Seems that the Cadi 6L80 has a shallower pan, and the G8 Pontiac has a shallower pan (2.5"). So the filters from these trans will allow a shallower pan. It may ultimately require a custom pan that is as shallow as possible for reasonable ground clearance.

Commented above that it is looser than the 4L65. While the 6L80/90 is taller, the 4L65 has a pan which is much wider. There is better clearance low down on the 6L's. The shift shaft on the 4L65 almost touches the tunnel wall.

Currently working on the cross member requirements and getting the sheet metal requirements finalised and the tunnel closed up, engine pan steering clearance needs, then on to exhaust, driveshaft, engine build etc.

That's all for now. More pix and details later as I get a chance. I am really looking forward to getting this on the road.

Enjoy....

Black02SLPSS

iTrader: (5)

Nice conversion. Seems like its an adventure so far. Good luck

BRPhotrods

iTrader: (3)

Cool conversion! I have not seen one of the six speed auto in action myself. If you need any help with a conversion kit just let me know id like to get a crossmember ready for the 6L80/6L90 transmission. Give me a call about the project and maybe we can work something out for your car.


Thanks
Phil Brewer
770-751-0687
www.BRPhotrods.com

rsz288

Thanks for the best wishes...yes "adventure" is the right word...

rsz288

Thanks Phil. Looking at the x member possibilities today/tomorrow. Will try and give you a call sometime if I can get the times right. You are in GA right? Is that EST or EST -1?

Cheers.

BRPhotrods

iTrader: (3)

I’m eastern standard in Georgia just give me a call 9-5 tomorrow I have sent about 10 of these LH8 pans and conversion kits to Australia and tons of phone call in the past 2 months how’s the supply of donor LS powered car down there? I look forward to hearing from and congrats on snagging that 6L90-E

Jrod79TA

Congrats on the 6L90! I've been trying to sort out which route I'm going to go with on my '79 Trans Am, and I'm sure I'm going to go for the 6-speed auto.

Have you thought about manual shifting the transmission? I'm wondering if all 6L transmissions have provisions for manual shifting like is available in the G8. I haven't looked into what 6L-equipped vehicles do and don't yet. And I'm wondering if Speartech or anyone else is working on something to allow a person to use paddle shifters, and if they'll have a total solutions kit for someone wanting to run a Gen IV engine, 6L80/90, and paddle shifters for manumatic mode....

rsz288

Hi there JRod, thanks for the note. Yes I will use what GM calls Tap Up/Tap Down - TUTD. Speartech has this all sorted and working and will do likewise here.

At present though, the PCM/TCM pair are quite protective of the trans. i.e. the shifts have been reported (mainly by G8/VE Commodore performance enthusiasts - though also have seen some similar Vette 6L80 feedback) to be relatively slow using TUTD. Engine torque is reduced on the shift to give a nice smooth shift which is safe and warranty friendly.

Am sure now that these trans are seeing aftermarket use, that the trans experts will see that they are viable propositions and will start to work their magic on them and TUTD will be more like an SMG.

Cheers.

Jrod79TA

I know the 6-speed auto debuted in 2006 MY Corvettes. Supposedly, for MY 2007, they reduced the shift times for the 'Vette. For a quick solution, do you think a PCM/TCM for a '07+ Corvette could be a viable option?

How are you planning on operationg the TUTD functions? What hardware are you looking at using?

rsz288

There is no LS7/6L80/90 combination offered by GM, but Speartech has these running successfully in the market, so I guess his setup is the best/easiest way for people to go in the US. Doubt anyone outside of GM officially knows how dependant the ECM and TCM are on each other, but it has been proven that they are co-dependant for optimal trans/engine operation.

It will be an interesting area of experimentation....though these 6 speed transmissions while mechanically quite simple (relatively), run on "black art" and are reportedly easy to fry if the shifts are set sub-optimally, so I dont intend to be too adventurous for some time yet. Though always interested in hearing from those that have been there and done it with the A6's.

On the TUTD, I probably wont run paddles straight up, more likely simply a shifter selected mode for manual shifting....depending on what shifter I end up with. Speartech, if not already, will no doubt offer the control setup with the right switch components and wiring for the electronics.

There are guys running 12 flat with near stock (tune+exhaust+ET's) 6 litre/A6 3800lb G8/Commodores in summer temps, so the trans does well off the shelf.

While I think of it, the 6L90 runs a different output yoke to the 6L80. Truck size plus! The output shaft is about 1.5" in diameter. Early indications were that a TH400 yoke would work....turned out to be a myth....

Cheers.

poorhousenext

RSZ,

Great to see you are doing 6L90 6 speed installtion. I'm working on one at the present too, only I'm using 6L80 instead of 6L90. Trying to shoehorn it into a resto-mod of 66 Vette. I'm waiting of frame to ship so I can see how bad of a tunnel interference problem I have. Was hoping none to little as I think tunnel is little deeper than camaro's, but a 6 speed manual installation requires tunnel modifcation due to it being hugh up front like the 6L trannys.

Another member here has been trying to decide if he wants to install 6L in his 69 camaro. So you are a big help to him now on making that decision.

Here's link to my conversion.

https://ls1tech.com/forums/conversions-swaps/884366-1966-corvette-ls7-6l80e-project.html

By the way what part of OZ are you from. was just down there last year visting friends and touring country. My freinds all live in NSW Sydney area and race motorcycles.

Have you ever heard of a gentileman by the name of Kim Baker. Has a shop close to Orange, NSW. Builds lots of race motors of all types and HP shootout motors for people. Also designed and builds dynos, both engine and chassis. Super nice person. Got to spend a day at his shop talking HP with him.

Cheers
Jere

BRPhotrods

iTrader: (3)

Jere,

Your in Tennessee right? I’m in GA just outside of Atlanta and near you and if your willing to bring the vette to my shop I would like to mock up a kit on your vette. I have the motor mounts and all I need a car so I can build the cross members off of. Ill give you a free kit for mock for your conversion so hopefully it will be worth the trip if you if your up for it?

RSZ

You took some great photos of the trans in comparison would it be ok if I used those images for informational purpose for other in the future who might take on this conversion?

Phil

poorhousenext

Phil,

I'm going to PM you about this. My chassis setup may be of value to you and it may not.

Jere.

rsz288

Hi Jere, yes I read your posts with interest a few weeks back when you intially put the pics on line. That'll be one cool Vette when its done. These 6L's are full of surprises. No wonder GM uses 3D modelling software these days.

Am on the east coast and aware of the Bakers. They are well known for as long as I can remember. Understand Kim & family moved out to Orange from Sydney as part of the retirement plan. He is still one of the most popular and top quality engine guys around. Especially in the race community. Apparently he gets more calls for work now than he ever did.

Its good to see some 6L80/90 projects underway now. When starting down this road there were none. Then Speartech, V8TV 66 GTO, and you. There must be more hiding out there.

Cheers.

rsz288

Phil,

Good to talk to you. Yes feel free to use the photos. They are in the public domain now. I will mail uncompressed originals.

Some more shots follow of the rear X member situation. The TH400 x mem looks like it would work, until the fact that it sits in a recess in the floor is taken into account. To work with the A6 it needs to be moved back so the front bolt goes in the rear hole. Then it no longer fits the floor.

I am thinking a simple straight piece of SHS or round tube suspended on plates mounted based on the original locations will work. Working that now.

Cheers.

rsz288

Hi All,

I promised more photos. The following are focussed on the rear cross member situation and the pan to ground clearance.

It is possible that many will be ok with the pan clearance as is for the 6L90. I will probably modify the pan so it is 3/4" shallower to gain some extra clearance. Would like to go more, but I dont know of any GM filters which will allow this. Yet. We also have a 4" rule here. A minimum of 4" clearance under any car for a roadworthy pass. Also it should live longer with more clearance.

There are more options with the 6L80. It has both truck and car pans. Car being shallower by around 3/4". I have seen GM photos which show a 6L80 pan which looks 1 1/4" shallower than the truck pan, but cant get any confirmation on this from anywhere. The photos say Cadi STS-V. The Cadi part number points to a truck/Vette pan.

TH400 X member in place for trial fitting...the dimension from the trans mounting face on the engine, to the centreline of the bolt holes for the rear trans mount is 26 3/4" +/- 1/8".


Pan hanging below sub frame rails...


Forward face of pan below sub frame rails...


TH400 X member from LHS showing precision 3 x 2 pine shim...the TH400 X member has been moved back so its front bolt hole is over the rear bolt hole in the subframe.



Rear X member from above. Shows clearance to X member even when moved back. In original position, 100% interference.



Rear X member from RHS..precision pine shim has trans sitting at approximately the installed position.


Rear x member from RHS under...


View towards front on LHS...


Rear view. Note monster truck yoke for 6L90.


The adventure continues. More trial fitting....

Cheers.

rsz288

Hi All,

Thought some of you may be interested in a slightly different exhaust option. While most everyone, understandably, goes with tube headers, I had not seen stockc ast iron headers used in a Gen 1 Camaro LSX conversion.

Doing an LSX and 6L90 conversion all at the same time is a lot of stuff at once, so I wanted to simplify wherever possible. I intended to go with factory cast iron exhaust headers for this reason. Further down the track it will get tube headers...like when the body is in the paint shop...but for now....

The stock GTO style headers that I had were like a pair of wings. Even the BBC used far less space. The RHS would not fit with suspension and engine mount interference, and the LHS had no chance with the steering box.

I thought the G8 Pontiac/VE Commodore factory headers may fit as the appeared to be more compact. I cant imagine these headers are G8/VE only, so maybe they appear on other GM models too. We dont get F Body headers out here that I am aware of, and I dont know if they fit in Gen1 LSX Camaros.

Photos below show that they are a good option and do fit with good clearance, though the steering box is still close. At present it shows 1/16" clearance, and some slight profiling of the cast iron will double this. I used ATS mounts, so the engine sits almost as low as it can go which helps reduce the tunnel cutting a little. I also chose to move the engine forward a 1/2" for additional trans and alternator room. I would guess the BRP mount kit would have even more clearance to the steering box.

I know I should do a nice set of headers, but these manifolds have made life just that little easier. For now.



Still good daylight to the steering box. The heat shield fits with a little mod.






FWIW.

Cheers.

philntx

iTrader: (8)

Can you post a picture taken from the transmission side, to show how much the exhaust flanges look along side the engine?

rsz288

Sure Phil, there you go...

rsz288

Had some PM's re ground clearance and the tunnel revisions, so some additional shots showing current ground clearance:

One shows the trans clearance is around 4.75". (120mm). This is with the trans sitting through the tunnel roof cutout by an average 0.7-0.8".

The other shows front crossmember clearance. It is around 6.9" (175mm).
The car overall will be 1.5 to 2" lower once finished. Say 5" at the front cross member, 2.75-3" at the trans pan (stock depth 90 pan). If the tunnel had not been cut out, and assuming around 1/4-3/8" clearance from top of trans to tunnel, the trans pan would be around an inch lower again: 1.75-2" ground clearance.

With the tunnel cut out, and a trans pan that is around an inch shallower (filter permitting), I should have 4-4.5" clearance at the trans pan. I will get the exhaust pipes to run about 1/2" lower than the trans pan for early warning. Plus maybe use a skid pan at the front for additional trans pan protection. May end up needing air suspension.....anyone have feedback on how this rides and functions?





The PM's tend to indicate that there are some folks out there who are thinking seriously of doing this conversion, or have made some degree of progress. Please dont be shy to post any findings you have, or ideas, or gotchas.

Thanks & cheers.