If there was a way to block you I would. You’re so arrogant claiming that all this info is proven. The only thing I agree with you on is that doubling the rated hp for a car equipped with a 4T65 is bound to have issues with things. I have never blown up a 4T65 and neither have any of the builds I’ve done.

As for my presence in this forum I don’t feel my 15 years of mechanical or hot rodding experience is needed. Bumpin has ALL THE ANSWERS and the only correct opinions.

As far as me name calling, I just call it how it is.

Peace out and good luck to anyone with a legendary Monte Carlo.

 

It's not arrogance, its confidence from being involved with this platform for 20 years and having one of the most heavily modded cars on here. If there's something you disagree with, please point it out and I'd be happy to dig you up several threads of supporting evidence from across the various 3800 boards. Given the peak of 3800 racing happened a decade ago, there's tons of historical data out there to support.

Out of curiosity then, what is the highest hp or quickest 1/4 mile car you've built? Also curious what tire and what mix of street / track use? Stock trans on all of them since its so strong, right?

Don't get me wrong, I'm not trying to say its impossible. Certainly with all of the historical data out there, its possible to over build the trans to stay ahead of the mods and make it last longer, I've just never seen any heavily modded 3800s that actually use the thing especially at the track over the long term NEVER have a single failure in their whole life, much less the hundreds you claim to have built.

I don't get why you get so upset when a single person disagrees with you. You get like this in every technical thread we don't agree on. You refuse to post any actual support for your claims and immediately get all emotionally worked up about it. Everyone isn't always going to agree with what you post online, there's no reason to go nuts every time.

Nice snarky twist there bud. Doesn't bother me personally coming from some random dude on the internet. TBH it makes your point look even weaker when we're 3 posts into a technical argument and you default to that instead of trying to actually defend your argument.

 

So maybe I could build on that to explain my perspective a bit.

I'd consider the 3800 SBE a strong engine (over engineered). It makes 200-260 hp, but has been proven to do 200k+ with ease and can handle 600+ whp (more than triple its stock power).

Same with something like a GM 5.3 V8. Makes 300ish stock, people push the SBE to 900, 1000 whp. Again, a strong engine.

Now the 4t65. Put behind engines from 200-300 hp in its later years. Extensive documented failures at stock power behind the 300 hp engines. Literally can't handle stock power.

Put behind engines with 250 whp, yet can snap the input shaft at 300 whp. We're not talking double the stock rating, we're talking 20% more a key hard part is at risk. Not much past that, chain failure, and so on and so on.

Like previously noted, even if you went out and bought the best of the best new aftermarket parts available today, you literally couldn't build a 4t65 to hold a hard-core 3800 turbo build with actual track use much less a hard core turbo LS4 build.

No trans should struggle to handle stock power long term. IMO, that alone makes it something less than adequately engineered. Maybe I'm overly bitter because I was one of those people with a stock LS4; but no one should be worried about actually using their car's power because they're afraid the time bomb transmission will leave them stranded and out thousands for a repair (ironically almost as much as the car is worth because no one wants to buy them due to the trans issues).

 

Since this thread is hosed anyways and the OP never responded back with the basic info needed to move forward anyways, I'll give you another story to try to articulate my viewpoint a bit better.

Graduate college and am looking for a first car to replace my old GTP which had its fair share of issues due to age / mileage. Was looking at a very low mileage used car to save some money. Came down to a Solstice, TBSS, or a GP GXP. All 3 right around 20k, all 3 with single digit thousand miles and zero issues. To keep the story short, I went with the GXP for the v8 power and sound and familiarity with the platform that being my 5th or 6th W at that point. Figured that would be a DD for awhile and eventually retired to a forever car as being the best of the best last hurrah for the W platform.

Drove it for a good number of years as either a DD or at least a few times a week car and absolutely loved it. Took excellent care of it as i planned to keep it forever.

As the LS4 cars aged, I started to see threads pop up about trans failures. Then more and more and more. I always thought -that won't happen to me, I take good care of it and drive it very gently for what it is capable of. I did take it to the 1/4 track one time for a handful of passes - not back to back and zero burnouts. Besides that, the car was very infrequently pushed to WOT at all.

The threads kept piling up and some boards started a registry of how many failed transmissions there were. Got more nervous, especially as the values really slid as there was no way to sell it and get into anything else near as nice, so I was basically lcoked in for life. The more of those threads I saw, the easier I got on the car. Also kept me from really modding it at all. Just had a crappy K&N kit and a cutout, both just for sound. Never did anything else for power in fear of hurting the trans.

The trans issues started about 50k. Initially it was rare hit and miss issues, so I hoped that just keeping up on fluid and filter changes it wouldn't get worse. But of course it did. The trans issues piled up and by 70k (75? Somewhere in there) I was reaching out for built trans quotes and shipping. All of which were nearly the full value of the car even with me doing the R&R. On the upside I could do a well built aftermarket parts trans to hopefully never have issues again, on the downside I didn't want to sink that kind of money into the car. We were close to selling our house and buying another, and I sure didn't want to blow that much cash.

Luckily (unluckily?) I didn't have to make the call. A distracted semi driver rear ended me at a dead stop and destroyed the car. Used that money with some cash on top to go to a totally different platform to not have to mess with that situation again - got a GTO with the T56. Been DD'ing that for years now with zero issues and have enjoyed every minute of it. Tons of WOT, plenty of ripping on it with no fear of the trans barfing all over at stock power. Makes me regret wasting all those years babying that GXP because of the 4t65. Its certainly not enjoyable to worry about it every time you get a open on ramp - is this gonna be it? If I give it a WOT rip here will it finally completely explode? What will I do if it does - part out this otherwise mint car or sink almost all the value into a rebuild?

That feeling sucks and is part of the reason I'm so bitter about that garbage trans. I get it on my other failures - those were really pushing it with lots more power and actual racing, but this - 250 stock whp street car and I'm worried? No, that's a garbage move on GM's part and part of the reason why ill always stick to it being a garbage trans. I'm not alone either, those threads across the various forums have racked up hundreds and hundreds of people with absurdly early trans failures. The crazy low values further reinforce that there is a well earned stigma against that thr LS4 cars. It truly makes me firmly believe, that amount of power (torque really) is beyond the capability of that stock trans regardless what minor upgrades GM did to justify it to themselves on paper.

 

One last point here to truly show how underperforming this trans is compared to the engine and why most of the big dog builds have left.

Say someone was building a brand new budget W drag car today.

Clean shell - $1k
Junkyard 3800 - $500
E85 injectors $300
Fuel pump - $250
Meth kit $400
Big turbo cam with supporting mods, minor head machining $1k
Turbo kit $5k (used kits run much cheaper, entry level ones starting used about $1500)
Dumped downpipe $100

Total so far- $8500 is, assuming you're buying most of the parts new besides the engine and car. Doesn't include a tune as the variability there is huge ranging from DIY on a $150 DHP box or trailering it to a major 3800 shop for a dyno tune. Also leaving out wheels / slicks as the variability there is all over also from stock wheels on cheapo slicks to high end race wheels with big brand slicks.

With something like that 500+ whp and 10 seconds are within reach especially in a gutted drag car.


Now for the trans. In a RWD setup of similar power, maybe you do a junkyard 4l80 rebuild or a moderate build glide and it would last forever. Not here. It nearly doubles the cost of the entire build just for the trans:

-GMR input shaft $1300 + (last new one I saw for sale, who knows used/ discontinued)
-GMR 1" chain $2650 (latest post price from an individual, discontinued so they fluctuate)
-GMR diff - $1000 (total guess roughly based on a Quafie- they don't come up often)
-GMR 930 axle adapters - $500 (again, rough guess as they don't come up often)
-Meziere flex - $400
-Precision converter $1k (average between single and multi disc)
-Trans anti flex brace $?? Custom (unless you can find a unicorn GMR trans case with the extra thick case, but I've never seen one come up for sale used. I have however seen a broken '800 hp' GMR input shaft blamed on case flex)
-Custom axles $?? Depends how much you DIY vs shop build and what parts you need to buy.
-Billet 3rd piston $160
-output shaft $200
-Pump shaft $130
-Reconditioned / upgraded valve body $350
-Then you've got all the standard rebuild parts and high performance clutches and such along with professional assembly.

Worst part is you can't even buy some of this stuff at a store. Its either long since discontinued or custom. So you're 100% at the mercy of the one person who happens to be selling at the time.