[ponjohn]

This is of interest to me.

I plan 46x build, 4l80e. I was going to use a 3.70 gear in a 9 inch.

What I am challenged with is the cam selection, how do you know that cam will tolerate being locked up at 1800 -2000 RPM?

I hope this adds value to this thread.

[JLMounce]

You're going to have to go with a really big cam in a 46x build to have it be bucking on you in the 1500-2000 rpm zone when locked up.

my cam is a 240/248 on 112 in a 465, 4.21" stroke engine. I lockup my converter in 3rd and 4th gear for cruising with minimum rpm set at 1400rpm. Other than the abrupt lockup my setup has due to the triple disc clutch, the engine doesn't care that it's locked up that low.

With a 3.31 in the rear and 26" tires, I cruise at 75mph around 2400 rpm and the car is incredibly happy in that range. In fact it doesn't mind anywhere in 4th gear where it's locked up. That's typically around 50mph on.

[blueghoast]

Originally Posted by Formulajones

Mine is setup like that and cruises in the rpm range you posted with 4.10's. actually drives nice like that but unfortunately it does not get to the end of the 1/4 in 3rd at my hp level. Steve at Hughes that built my 4l80e and converter told me he didn't want me to lock the converter at full throttle and it would be iffy if I tried to use 4th. Meaning he knows people that do it with his trans and most of the time get away with it but 4th in a 4l80 uses a single clutch/plate setup that isnt meant to hold a ton of HP. Since I was at a private track rental and out of gear at the 1000 ft mark I started using 4th. All was fine but I will say it's not ideal in a drag race situation because it pulls the motor down so much it basically kills the run.
For instance in 3rd I was banging the rev limiter at 1000 ft. I kept my foot in it anyway and ran out the back. Went 11.10 at 121 mph.
Next pass I used 4th for the last 320 feet or so and only picked up 1 mph. Went 10.90 @ 122. Using overdrive at the strip isn't ideal obviously and you can even hear it lug down in videos I shot, which is why I'm Knocking the 4.10's down to 3.55's. I sent video to Steve and talked about the converter as well. He wants to loosen it since it only flashed to 2200 and said 3.55's would be perfect for my setup. I'm making 786/772 HP and TQ so I just dont need the 4.10's anymore and it's why i said early on the gear ratio is dependent more on the engine combo if you're worried about 1/4 mile racing and not so much cruise rpm. The overdrive is just an added bonus. Problem is this stuff takes a ton of testing and time. I'll have to swap the 3.55's and test again with the tight converter first and log flash rpm at the starting line because the gear change will affect the flash rpm and how the converter acts on gear changes. Then Steve will determine if and how much the converter needs restalled or reconfigured. Then reinstall that and test yet again. We are shooting for a converter that flashes around 2800-3000 because the engine is already making over 700 ft lbs at 2700 so I just don't need or want a ton of converter in it.
I say all this because this becomes a game of testing and changing parts. How much are you willing to do and how much money do you want to spend? How good do you want it to run? Every combo is going to be different.

If it were me I would go with the 3:73 first with the converter as it is.
That would take a lot of testing out of the situation, if it don't like that
then I would go the 3:55 route, I really think that you are so close now
that it might be of benifit. Hope this helps a little and not hampper ya.
At leasted it's something to think about.?

GT

[Formulajones]

Originally Posted by ponjohn

This is of interest to me.

I plan 46x build, 4l80e. I was going to use a 3.70 gear in a 9 inch.

What I am challenged with is the cam selection, how do you know that cam will tolerate being locked up at 1800 -2000 RPM?

I hope this adds value to this thread.

That's the beauty of having an "E" transmission such as a 4L80 or 60. You can precisely control the lockup via laptop and make it do whatever whenever you want. That's why I love these electronic control transmissions with radical engines. I can run around in 4th gear and make the converter lock or unlock in any condition. Just takes a little test driving to see what your engine tolerates and then adjust accordingly.

[Formulajones]

Originally Posted by blueghoast

If it were me I would go with the 3:73 first with the converter as it is.
That would take a lot of testing out of the situation, if it don't like that
then I would go the 3:55 route, I really think that you are so close now
that it might be of benifit. Hope this helps a little and not hampper ya.
At leasted it's something to think about.?

GT

You are correct, knowing what the 4.10 does at the track now and doing the math a 3.73 would be nearly perfect for 1/4 mile performance with my engine/weight/tire combo. And there is a possibility I still may try that. The 3.55's I already have sitting here in a box from a previous project which is why it was in the works first. My only issue is waiting for a 3 series tru trac to show up since I'm running an old Moroso Brute posi unit with the 4.10's.
I'll save that stuff for another project that needs more gear.

Either way I have to settle on a gear first, track test the car and log what the converter is doing before Steve will make the necessary converter changes for me.

To give a better idea what I'm dealing with and trying to explain.
You can see the 1000 foot cones and hear it go into 4th right there and bog the engine down.
https://youtu.be/wtNY3FS7bVI

Funny thing is leaving it in 3rd and banging the rev limiter to the finish line only loses 1 mph. So 4th isn't really doing anything other than saving the engine.

Here are 2 different views of the same pass with the headers open, easier to hear it. In 4th is just doesn't gain any rpm at all and just basically stays there. You wouldn't think with 772 ft lbs. that it would drag the engine like that and it would just pull through it, but the gear multiplication just sucks horribly when you use overdrive. .75 overdrive with 4.10's is basically going from 4.10's and jumping down to a 3.07 gear in a split second. That's a major gear drop.

https://youtu.be/q-R0O3Plk2I

https://youtu.be/86mdFBz_Raw

[MerrittE]

Here are a couple of tables I put together to help me zero in on gearing. They work better in Excel where you can filter the columns to show a specific tire size, gear, etc. but I can't attach them that way, so I hope they are helpful as PDFs. I wanted to see what RPM I would be turning at highway speeds as well as what my speed would be at max RPM for each gear.

4L80E_Tables_RPM by Speed OD (55-80).pdf

4L80E_Tables_Speed by RPM and Gear.pdf

[yellow1098]

Those tables do work pretty well….I used them when I installed my 410’s and they were pretty dam close….

Also for formula…I checked my data logs and I dont get into 4th gear in my 1/4 mile runs…..maybe cause my 60 foot sucks haha

[Formulajones]

Yeah my 60 foot was not as good as it's been either since this converter is super tight now. It only flashed to 2200 and was going 1.57 all day. Not where it usually is. But the HP is a big player in that scenario that the math tables don't account for.
A lower HP car will get to the finish line in 3rd with 4.10's no problem because it's not accelerating as hard. Make more HP and now it goes through the gears quicker, accelerating harder, next thing ya know, you're out of gear.

For instance, I've had 4.10's in that car since 1987. When the 454 was bone stock it worked great at the track, cross in 3rd no problem and that engine was only good for 5000 rpm. I started upping HP, 4 different incarnations of that 454 over the years, each time it was crossing the finish line at more rpm. Last 454 made 600hp, crossed the line in 3rd at 117-118 mph right around 6000 rpm. Was a really nice setup that was happy.

Current engine is making 786 hp. Same gear. Now it's banging the rev limiter at 6200 before the 1000 foot marker in 3rd gear. It's not even close to making it to the stripe. 4.10's work great for 600hp, not so much at nearly 800 hp.

That's what I was trying to convey in my first post and which scenario was more important to the OP. Do you want optimum 1/4 mile and let the overdrive cruise rpm fall where it may, or do you want a certain overdrive cruise rpm and sacrifice some 1/4 mile performance.

I'm of the first thought process when it comes to overdrives. I'll run a gear that suites the engine best at the track, and then just let the overdrive dictate where the cruise rpm is. Because even my street cars, being street cars, still have to run as good as they look, and as good as I think it's capable, and I'll go though a lot of testing until it gets there.
For me, having 4.10's in this car for nearly 40 years, and 35 of that without an overdrive, cruising at 3000 rpm just does not bother me like it bothers others. I grew up doing it all my life. So when the overdrive made it possible to cruise this car at 75 mph at 26-2700 rpm I have absolutely zero problem with that. Hell I drove it 250 miles that day to and from the track, raced it all day, and drove it home. Never so much as turned a screw driver on it. I've done that for decades with this car without the overdrive, cruising 3000 rpm and barely going 60 mph LOL.
I have to change the gear however because now it's just simply too much for 1/4 mile racing with this engine. Cruise rpm comes second.

[MerrittE]

You're hitting on exactly what's going through my head and I'm falling into the latter camp where I'm going to give up a little 1/4-mile performance to make a comfortable cruise rpm.

This has me leaning towards a 3.55 gear ratio which looks like a good split for what I'm after. About 2,700 rpm at 80mph in OD and topping out in 3rd at 5,500 rpm at about 122 mph.

I know I won't be hitting 122 in the 1/4 but with 4.11s I would likely bump into OD,

Thanks for all the info it's really helping me wrap my head around things.

[yellow1098]

That makes a lot of sense…Im right at about 650hp and it times just about right through the finish line before it shifts into 4th…..any more power and I might be screwed ….when I add the nitrous I might have to think about that

[Formulajones]

Yeah nitrous will change that lol.


To be honest, in general, a 3.55 or 3.73 is a pretty nice way to go with overdrive. It'll do everything pretty well regardless of HP.

[HWYSTR455]

Yeah I found that 3.73s are pretty much the sweet spot for 600+ hp, the 3.55s are only like a 200-300 rpm diff.

For grins, on the 535 engine I did 3.42, and now wish I would have done 3.73s.


.

[JLMounce]

You guys are going to make me want to put 3.73's back in my car.

unsubscribing...

[Formulajones]

Had 3.73's in dad's 571ci Pontiac for a while. Had 4 different converters in it trying to get the car to work and they were all loosy goosy. For what ever reason 2 converter companies just couldn't get a handle on it. I think that gear would have worked nicely if we were willing to keep trying converter companies, lol. But it wouldn't make it to the stripe either because the converters were way too loose. That's just another variable.

I think 3.73's would be about perfect if it had a converter that would get a hold of the engine. Eventually when the 4L80E went in that car I swapped it to 3.42's. Works good at the track. With a proper converter it's gone 1.47 in the 60 in a 4100 lbs car is doing pretty good, and crosses the stripe at 5400. 10.60's at 128. Shifts at 5800 so yeah it could use a little more gear and it might pick up a smidge. It's not working hard at all at the finish line.

Whether a certain gear will work good or one possibly better than another depends on how much torque you're making and if the converter does it's job. A 4L80 only has a 2.48 first gear. If it's a heavy car and a snug converter, you'll need a bunch of grunt down low to get the thing moving if you only want 3.31's or 3.42's. Otherwise it kind of turns into a slug in the 60 foot.

[JLMounce]

I use a triple disk lockup converter. Although I wouldn’t call my TSP really loose, what looseness it does exhibit is moot once the lockup engages.

[Formulajones]

I had trouble with those once we reached a certain hp tq level.

Mine were a little loose with 600hp but not horrible. What I didn't like is that it never would couple well enough at moderate rpm so when the converter did lock it was violent and a huge rpm drop. There was no amount of trans tuning that made it livable. Ok for a weekend toy but that got annoying after a few hours of driving. With more power that got even worse. They were just too loose under normal driving, making lockup too drastic.

Hughes was the first custom lockup converter I've had that actually couples very well at moderate rpm levels so lock up isn't a drastic rpm drop and not nearly as violent. Almost stock like, but it'll flash up nice when you get after it.

It's a fine line of too much or not enough. I spent about $6000 with different converter companies in a short amount of time till I found something I'm happy with, performance good at the track and drives nice without violent lockup. Hughes, for me anyway, has been the best at getting it pretty damn close on the first try.

I do like tsp however in non lockup turbo 400 stuff. That seems to work decent enough. Maybe not coupled as well as a couple others I've tried but ok as long as you aren't making more than 600hp/TQ. That's another subject entirely with a whole page of experiences I've had with that deal.

[HWYSTR455]

Originally Posted by JLMounce

I use a triple disk lockup converter. Although I wouldn’t call my TSP really loose, what looseness it does exhibit is moot once the lockup engages.

I have a TSi triple, and feel the same way. It's a little loose and would LIKE it tighter, but it's lower on the list of stuff I still need to hash out on that car.

When I was freshening the engine for the build, I had CK go thru the trans, he found nothing wrong with it, which was good to hear. I also asked him to send the converter back and have them tighten it some. It is a 'little' tighter, but still a little loose for my taste.

I also bought another converter at the same time which I plan on using on the 442. When ordering that I asked them to make it 'very tight', and the response I got was that you can only make them 'so' tight in a 10" converter. Not sure how true that is, but so be it. It's rated at 2500-2800.

https://www.tsirace.com/

CK says their' converters are top notch, many use them with no complaints, so feel good about using them.


.

[JLMounce]

The lockup on the TSP unit is a bit harsh, but that is to be expected from a clutch pack that is either on/off for the most part. There's too much material there to really "slip" in any meaningful way.

I have tuned the lockup as such that driving it around casually is acceptable. Yes you feel it lock, but it's not jarring. When it locks under WOT, you know it, as it kicks you like a gear change. I actually prefer that if I'm being honest.

I've heard lots of good things about the hughs lockups. If I ever do something else I may have to consider that.

[Formulajones]

I probably didn't explain that clearly before. I like them to lock up firmly. I actually tuned all my LS stuff that way back in the day as the factory tunes would engage them soft. I preferred to not have the slippage.

The issue I have with the TSP isn't that it locks harshly, but the fact that the converter itself is not coupled that well when it's not locked, makes the engagement that much worse. In other words it's slipping so much even under very light throttle, that when it locks it's a drastic rpm change. I'm talking as much as 1000 rpm drop. It shouldn't be that way if the converter is coupling and designed well for the application it's intended for. A more typical rpm drop at light throttle lockup would be more like 400-600 rpm at the most. That's how my Hughes converter acts and it's a pleasure in comparison.

As far as making them tight, if the company can't make a converter tighter for your application (I've been down that road) It's probably time to look elsewhere. The way it was explained to me by Steve at Hughes is that at higher power levels the smaller converters are only going to be so tight as Highway was told. The cure for that is to build a larger converter as Steve put it. Steve has told me more than once it's much easier to make them tight to start with and loosen them progressively. Starting too loose and trying to make it tighter is much more difficult and not the way they prefer to do it as it can turn into a real fiasco. And so many companies seem to start too loose.

In my case, I took the 9.5" TSP in to Steve, he took one look at it, noted the style of plate on the back side (there are 2 styles) and said point blank, there is no way I'll be able to make that tight enough, you're going to have to start fresh with a larger 10.5" unit. He is very familiar with building converters for Pontiacs and trying to harness torque early so I let him do his thing. He's done 2 of them now and nailed them both, and is about to do a 3rd for me. I provide dyno sheets, scale the cars, and of course provide gear and tire size and he runs with it.

[HWYSTR455]

FJ - Do you use Hughes for your 4L80Es? Curious how those are.



.