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I Dyno-tested my truck today. I replaced the stock exhaust with dual Borla Pro XS mufflers (cat back) and a drop-in TRD hi-flow filter. The dyno showed a consistant 308-310 hp at rear wheels in 3rd gear. 285 hp in a fourth gear run. Lower because the rev limiter is set at 100 mph. Torque was consistant at 318. The thing that was very noticable, the air/fuel mixture was very rich. Like< 10. After we took the the neg cable off the battery and let the cpu reset, we got the highest hp at 310 and the air/fuel ratio at 10.1. When someone comes out with a tuner I can actually produce near 325 by changing the air/fuel mix to make it a little leaner to 13. that's potentially another 25 horses. HELP!!!!!!!!!!:cry:
 

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Re: 5.7 sr5 tundra yno test results....

I dont understand the limiter statement ?
These trucks will pull to 115 mph @ 5200 rpm from a standing start.
Why wasnt a full pull done up to 5th gear ?Assumeing its a double OD is shorting the 4:30's out back.Theres
motor left to pull well into 5th gear

:confused:
 

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Re: 5.7 sr5 tundra yno test results....

I'm just reprting our finding today. I thik the speed limiter is set base the speed rating on the tires. I have the 18" off road tires. Once the truck got to 100, it powered down on the 4th gear pull. All three 3rd gear pulls yeilded 305-310 after the cpu reset.:cool:
 

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Re: 5.7 sr5 tundra yno test results....

that leads me to believe "corrections" can be made at the dealership.
Ill have to look into it here ......;)
 

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Re: 5.7 sr5 tundra yno test results....

I'm just reprting our finding today. I thik the speed limiter is set base the speed rating on the tires. I have the 18" off road tires. Once the truck got to 100, it powered down on the 4th gear pull. All three 3rd gear pulls yeilded 305-310 after the cpu reset.:cool:
Keep in mind that your exhaust system may be hurting you. There is something to be said about slapping an exhaust system under there that can also be slapped under a dozen other vehicles instead of one that was made specificaly for that vehicle and engine. I use to see it all the time with Rams and now I also see it with the MINI. There is a reason why a complete system from Borla, Magnaflow, and TRD costs so much more...........
 

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Re: 5.7 sr5 tundra yno test results....

Its not like those are horrible numbers. I consider myself lucky to be driving a truck where people complain about 300+rwhp dyno runs :D

Did you disable the vsc system and the safety nannies? That may have been the issue as well. Is the truck 4wd? (off road tire comment above) If so, that could explain slightly lower than expected numbers. Not even mentioning the different types of dynos.

I came from Dodge country and they were getting anywhere from 250-270rwhp, w/ the average falling around 260ish. So realistically, if 321rwhp is the average for the Tundras, anywhere from 310-330rwhp should be expected Id think.
 

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Re: 5.7 sr5 tundra yno test results....

Any idea what the same truck did on the same dyno with the stock exhaust and filter?
 

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Re: 5.7 sr5 tundra yno test results....

Interesting results. Any chance we could get a picture of the dyno runs?

Anyway, as I have posted before in other threads, tuning the air-fuel ratio has serious potential for gaining power and torque, especially recovering lost low end power and torque from mods like intake and exhaust. I used a Split Second PSC1-001 to tune my air-fuel ratio on a dyno on my '05 4Runner after I had intake and exhaust mods. I recovered significant low end torque and even added more peak power by tuning the air fuel ratio from 10.9 up to around 13:1. It was a pretty simple install which used a few inputs from the ECU and conditioned the O2 sensor signal which effectively tricked the computer into leaning out the mix to the desired value. I'm sure this can be done on the Tundra, just make sure you have a dyno and a wideband O2 monitor.

Hope this helps!
 

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Re: 5.7 sr5 tundra yno test results....

285 sounds like the more accurate number since it was in 4th gear. typically in 6-speed transmisions, 4th gear is a 1:1 ratio (or very close to it), making it the most "truthful" gear to do dyno pulls in.

were you saying that you were hitting a top speed limiter in 4th, or did you get a good pull all the way through 4th? if it was a good pull, it sounds like the 381 HP claim is a little optimistic on toyota's part, otherwise that would be nearly a 25% drivetrain loss, which is very high. since they opted not to go with the new SAE Certified measuring standard on the new engine, they could have tweaked out some higher numbers like they did on the 05 Tundras- 06 was measured SAE Cert. and "lost" 11 HP over the 05 model even though the engines are identical. it would make sense if they wanted to hit a torque rating of 400 lb-ft or more. makes me wonder why they would use the SAE Certified standard on the 4.7 but not the 5.7.
 

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I Dyno-tested my truck today. I replaced the stock exhaust with dual Borla Pro XS mufflers (cat back) and a drop-in TRD hi-flow filter. The dyno showed a consistant 308-310 hp at rear wheels in 3rd gear. 285 hp in a fourth gear run. Lower because the rev limiter is set at 100 mph. Torque was consistant at 318. The thing that was very noticable, the air/fuel mixture was very rich. Like< 10. After we took the the neg cable off the battery and let the cpu reset, we got the highest hp at 310 and the air/fuel ratio at 10.1. When someone comes out with a tuner I can actually produce near 325 by changing the air/fuel mix to make it a little leaner to 13. that's potentially another 25 horses. HELP!!!!!!!!!!:cry:
The reason the mixture is so rich is to keep the exhaust temps low at WOT to extend the life of the cats. Manufacturers need to maintain the warranty for the cats, so its extra insurance that it will last that long. If you lean it out, you may get more power but they may not last as long.
 

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Re: 5.7 sr5 tundra yno test results....

Something doesn't sound right. 15% power loss due to drivetrain is about the norm (381 x .85 = 323.85). Either Toyota is inflating their 381/401 numbers or something wasn't quite right with your dyno run. However, the test from Edmunds.com looks about what I would have expected. The Titan numbers look high and the Silverado numbers seem low in this graph.


 

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Re: 5.7 sr5 tundra yno test results....

Something doesn't sound right. 15% power loss due to drivetrain is about the norm (381 x .85 = 323.85). Either Toyota is inflating their 381/401 numbers or something wasn't quite right with your dyno run. However, the test from Edmunds.com looks about what I would have expected. The Titan numbers look high and the Silverado numbers seem low in this graph.



In a truck, especially w/ a 6spd, Id expect closer to 20% loss. Most all trucks Ive ever been around have seen in the ballpark of 18-24% loss. 15% is more in sportscar territory.
 

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Re: 5.7 sr5 tundra yno test results....

Interesting. What does the 6-speed have to do with it? I thought we were looking at parasitic drag?

The Tundra comes out pretty close in the graph above, so either they way under rate it or it was more efficient than 18%-24%
 

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Re: 5.7 sr5 tundra yno test results....

Interesting. What does the 6-speed have to do with it? I thought we were looking at parasitic drag?

The Tundra comes out pretty close in the graph above, so either they way under rate it or it was more efficient than 18%-24%
Considering the 6spd is a good foot longer than the comparable 4 speeds in other trucks, the loss Id assume would be more. Were it a manual Id say no, but its not.

Also, considering the rear gearing is the same size as others 3/4 ton pickups, I dont see it hitting a 15% drivetrain loss like a Vette or Viper.
 

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Re: 5.7 sr5 tundra yno test results....

Edmunds' dyno run yielded 321rwhp which is just about right when you factor in 15-20% for drivetrain loss.

I'm thinking that is pretty stout and nothing to complain about.

Too bad that there wasn't a before and after for your exhaust change as I bet that impacted your results.

Steve
 

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Re: 5.7 sr5 tundra yno test results....

285 sounds like the more accurate number since it was in 4th gear. typically in 6-speed transmisions, 4th gear is a 1:1 ratio (or very close to it), making it the most "truthful" gear to do dyno pulls in.

were you saying that you were hitting a top speed limiter in 4th, or did you get a good pull all the way through 4th? if it was a good pull, it sounds like the 381 HP claim is a little optimistic on toyota's part, otherwise that would be nearly a 25% drivetrain loss, which is very high. since they opted not to go with the new SAE Certified measuring standard on the new engine, they could have tweaked out some higher numbers like they did on the 05 Tundras- 06 was measured SAE Cert. and "lost" 11 HP over the 05 model even though the engines are identical. it would make sense if they wanted to hit a torque rating of 400 lb-ft or more. makes me wonder why they would use the SAE Certified standard on the 4.7 but not the 5.7.
Where are you seeing that the HP and TQ figures aren't SAE certified? I'm pretty sure the 381/401 is certified...

Yes, the tester's numbers in this thread is a little low, but there are so many factors involved, like altitude, humidity, relative pressure, fuel used, how new and broken in the truck is. I don't see this as anything to be really worried about and I think the engine lives up to each and every 381 HP. :D
 

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Re: 5.7 sr5 tundra yno test results....

What kind of dyno was this run made on? What type did Edmunds use? Dynojet, Mustang etc. They all get different numbers. Could be the explanation here also.
 

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Remember that if your truck is a 4x4 you have extra losses due to the transfer case as well as the transmission losses and differential losses.Therefore you will see lower output figures than you would see in a two wheel drive.
 

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Re: 5.7 sr5 tundra yno test results....

Where are you seeing that the HP and TQ figures aren't SAE certified? I'm pretty sure the 381/401 is certified...
Motor Trend denotes in their spec breakdowns if the ratings are SAE Certified. In the issue a month or so ago with the Chevy vs. Tundra article, the Silverado was noted to be measured using SAE Cert. and the Tundra was not.
 

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Re: 5.7 sr5 tundra yno test results....

Motor Trend denotes in their spec breakdowns if the ratings are SAE Certified. In the issue a month or so ago with the Chevy vs. Tundra article, the Silverado was noted to be measured using SAE Cert. and the Tundra was not.

All new engines are tested to the new SAE standard. "Certification" is an addition 3rd party witness to the testing. After reading Edmunds review and findings of the Silverrado's of a 4 second delay(until closed loop) on the actual horsepower that is advertised, it's probably better to look at vehicle weight relative to quarter mile trap speeds and 60 ft times.
 
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