CAMTuning 2.4L Tuning development with Cobb Tuning

[CAMTuning]

Nice!
Was this on factory exhaust also?

I have a Carven catback on the truck, but have done enough testing back to back with the stock muffler to know that it isn't a factor at this power level.

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[SC4Runner]

I have a Carven catback on the truck, but have done enough testing back to back with the stock muffler to know that it isn't a factor at this power level.

Would you mind sharing some audio/video clips with the downpipe? Cold start and while running in the cabin? I want this mod, but I don’t want excessively loud.

 

[CAMTuning]

Would you mind sharing some audio/video clips with the downpipe? Cold start and while running in the cabin? I want this mod, but I don’t want excessively loud.

Sure, I can do that. I have some audio with the Carven exhaust, which I took off today and put the stock muffler back on. With the stock muffler, I can't tell a difference from the stock downpipe.

 

[CuttingedgeSport]

Not to be the tightwad here, but have you considered running a different truck with the tune installed to see what is the max best safe power that can be obtained with all stock components on a 91 octane tune?

Coming from some big turbo builds, I understand all the reasons for larger, more efficient intercoolers, intake improvements, and the downpipe/exhaust size increases. I don’t want to downplay the importance of any of those good aftermarket parts that are available. I looked at this platform the same way before I decided I wanted this engine over the twin turbo 3.4L.

What I question is how far you can stretch a totally stock component 4Runner with an excellent and safe tune.

I know that the turbo upgrade is the last huge piece of the puzzle to push way over 450whp, but I question if all of the stock components could support ~320whp with just a tune.

 

[CAMTuning]

Not to be the tightwad here, but have you considered running a different truck with the tune installed to see what is the max best safe power that can be obtained with all stock components on a 91 octane tune?

Coming from some big turbo builds, I understand all the reasons for larger, more efficient intercoolers, intake improvements, and the downpipe/exhaust size increases. I don’t want to downplay the importance of any of those good aftermarket parts that are available. I looked at this platform the same way before I decided I wanted this engine over the twin turbo 3.4L.

What I question is how far you can stretch a totally stock component 4Runner with an excellent and safe tune.

I know that the turbo upgrade is the last huge piece of the puzzle to push way over 450whp, but I question if all of the stock components could support ~320whp with just a tune.

Yes, I’ve tuned my truck in completely stock form, and we’ve also dyno tuned many stock trucks (hybrid, and non, both on our dynojet and another shops hub dyno) on 91. So I’m not just stacking parts and guessing — I’ve seen what these do in factory trim.

On a fully stock truck, 91 octane, safe calibration, you’re realistically looking in that ~310–325whp range depending on dyno type and conditions. The factory hardware is actually pretty capable within that window.

Here's a our development truck, completely stock, non hybrid during early development.

Here's an example of 2 different stock hybrid Tacoma's (Sorry, no 4Runners, but same/same) with before and after results on 91. The difference of ~10whp in these on both baseline and tuned power is due to larger tire size on the 2nd graph (35") but the delta is nearly identical.

I don’t think bolt-ons are required to make good power safely. But I’ve still taken my own truck through the same upgrade path a lot of customers end up following so I can see exactly what changes, what actually helps, and what doesn’t. I’d rather test combinations on my own truck and gather real data before anyone else spends money on it.

 

[CuttingedgeSport]

Excellent breakdown on the power potential.

I will speak to you in the future about a tune on a Cobb Accessport.

 

[SC4Runner]

Not to be the tightwad here, but have you considered running a different truck with the tune installed to see what is the max best safe power that can be obtained with all stock components on a 91 octane tune?

Coming from some big turbo builds, I understand all the reasons for larger, more efficient intercoolers, intake improvements, and the downpipe/exhaust size increases. I don’t want to downplay the importance of any of those good aftermarket parts that are available. I looked at this platform the same way before I decided I wanted this engine over the twin turbo 3.4L.

What I question is how far you can stretch a totally stock component 4Runner with an excellent and safe tune.

I know that the turbo upgrade is the last huge piece of the puzzle to push way over 450whp, but I question if all of the stock components could support ~320whp with just a tune.

The estimated HP that I was provided with the SXTH CAI and a tune was 315-317, and those dyno numbers posted by @CAMTuning line right up with that.

 

[CAMTuning]

New turbo went in the truck this last weekend. Install was surprisingly easy compared to other platforms I've worked on. The shared oil feed/return line is nice. I did some road tuning on it right away, and performance was not a huge improvement.
I got it on the dyno to verify and did a total of 30 dyno runs dialing in a smooth boost curve (~21 psi tapering to 19-20)
These 91 octane runs are apples-to-apples with the previous stock turbo setup.

The new turbo does carry boost a little better up top, but the tradeoff was a noticeable loss in low-end response and only about an 11whp peak improvement over the stock turbo configuration. There's always a trade off in low end when you go to a larger turbo, but typically it comes with the reward of higher hp and torque in other regions of the powerband.

For context, the E30 comparison isn’t apples-to-apples because the earlier run was on the stock downpipe with the stock turbo, while the current setup is new turbo + high flow downpipe.

I didn’t design or spec this turbo myself — I worked with a turbo builder to try something different on the platform. That’s part of development. Sometimes the data confirms an improvement, and sometimes it shows the OEM setup was already very well matched.

My suspicion right now is that the turbine side may simply be a bit too large for this engine’s displacement and operating range, which hurts response and area under the curve even if it carries boost slightly better up top.

I’m obviously a little disappointed in the performance, but I’m glad we did the testing before ever promoting a turbo upgrade. This is exactly why I test combinations on my own truck before recommending them to customers.

I also think it’s important that when new hardware gets introduced on these trucks, real dyno data is shared so people can see exactly what the changes are.

Real development means putting the parts on the truck, running the tests, and sharing the results — good or bad.

Stock turbo will be back on within the next couple of days, and I'll decide what direction to go next.

Dyno charts below.

91 on stock turbo vs new turbo

E30 on stock turbo and new turbo (stock turbo was still on the stock downpipe). With more time I could have smoothed this torque curve, but the gains were going to be underwhelming so I just stopped here.

 

[CuttingedgeSport]

Hmmm, agreed on disappointment for gains vs. cost on this custom turbo.
I will be watching the FAFR big turbo thread to see what that does with great expectations.

 

[xp0nex]

Thank you for all the hard work you’ve put into this!

 

[CAMTuning]

Hmmm, agreed on disappointment for gains vs. cost on this turbo. Was this the TK500 or something else? Sorry if I missed that info.

I will be watching the FAFR big turbo thread to see what that does with great expectations.

This is a one - off turbo I had a reputable turbo maker build for me. It took almost 4 months, even though I was promised a few weeks. This turbo is not available anywhere on the market.

Good and bad update though, depending on how you look at it.

While reinstalling the stock turbo today I discovered the upgraded turbo already has compressor wheel contact with the housing and noticeable shaft play after less than 20 miles of use.


That obviously shouldn’t happen, and it likely means the turbo wasn’t operating correctly during the dyno testing. For now the stock turbo is going back on while I sort this out with the manufacturer.

Hopefully this turbo builder can fix it- but this is the cost of development.

 

[CuttingedgeSport]

That contact could certainly explain the difference in response and lack of larger torque and HP gains


I feel your pain. Pioneering any engine and turbo program is never cheap or easy, even when parts are good.

 

[Legend-GS]

@CAMTuning please share clips of the carven exhaust

Did it drone at all?

Sure, I can do that. I have some audio with the Carven exhaust, which I took off today and put the stock muffler back on. With the stock muffler, I can't tell a difference from the stock downpipe.

 

[CAMTuning]

Hmmm, agreed on disappointment for gains vs. cost on this turbo. Was this the TK500 or something else? Sorry if I missed that info.

I will be watching the FAFR big turbo thread to see what that does with great expectations.

@CAMTuning please share clips of the carven exhaust

Did it drone at all?

Yes it did drone badly with the downpipe. It wasn't bad on the stock downpipe. I was almost embarrassed to drive it once I put the high flow cat on. I want back to stock muffler for now. The only clip I have is on cold start, which is worst case.

 

[Legend-GS]

Yikes. Thanks for sharing. Too bad because I was about to pull the trigger on the carven. It sounds so good on stock downpipe. But I'd rather have a downpipe than cat back

Did I miss it, or can you share some clips with the downpipe and stock catback?

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Yes it did drone badly with the downpipe. It wasn't bad on the stock downpipe. I was almost embarrassed to drive it once I put the high flow cat on. I want back to stock muffler for now. The only clip I have is on cold start, which is worst case.

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