Doug Thorley Questions and Answers

[Beancounter25]

1. Pricing? How much are these going to cost?

Answer:

They should run in the ballpark of $650 for the ceramics.

2. What is the projected benefit of the headers?

Answer:

On the 4.7 Tundra we gained 28 hp and 39 torque at 3800 rpm. That is a huge power gain. Also anytime you increase efficiency your mileage will significantly improve as long as you keep your foot out of it.

3. What installation issues will there be for the do it your selfers?

Answer:

These will be a direct smog legal bolt on application.

4. The projected timing from when the 20-25 limit is met until we get them?

Answer:

4-5 weeks from time development is wrapped up.

If you're interested in these headers for the Toyota 4.7 V8, please leave a note attached to this post so I can get a count. I will also be posting this message over at Yota Tech and T4R.org, so please only post one time so I can get an accurate count.

REMEMBER, if you are interested in these headers, Doug Thorley will require you to contact them and leave a credit card number. The total BUYING customers needs to be 20-25 before they will start.

Thanks,
Brad

[Beancounter25]

Here is the dyno spreadsheet verifying the Tundra's numbers

[aws24689]

lemme think bout that one

[Beancounter25]

aws24689,

Thats the exact reason I'm posting this information - to get people thinking if they really want headers on their V8s. I tried to have installed Thorley's Tundra headers on my 4th generation but they didn't fit, and when talking to one of Thorley's sales reps about this issue, we came up with this idea that if 20-25 people are interested in having headers built for the V8, they would do it. I kind of got roped into putting this info out on the sites, but believe me, they have my credit card number – I want this to happen.

The folks that are interested should be discussing this idea/offer on the sites, and if they post that they "are in", I'll count them in to get an idea of where we are in the 20-25.

Thanks for your interest,

Brad

[Mikestang]

I see they have a dyno sheet to support their gains, but in all my years wrenching on cars and trucks I have NEVER seen gains of that magnitude from a simple header install on a naturally aspirated vehicle, especially from a "short tube" smog-legal design. YMMV dramatically.

[Beancounter25]

Mikestang,

It seems that while the company has provided a dyno sheet that supports their gains, you doubt the gains could be that great. Should I take that as meaning you’re not interested in purchasing these headers?

Thanks,
Brad

[Photog]

Those do seem like large gains. I see on the Dyno chart that the Tundra has a Cat-back exhaust conversion also. I wonder if the Cat-back is necessary to realize this degree of benefit. It is OK if true; but buyers may need to know that up front.

The manufactures today, tend to optimize the intake and exhaust to be compatible. Changing one does not improve overall airflow. Usually performance improvers have to be installed as a system, to see power/torque changes like this. Better breathing for the engine usually requires changes to the whole airflow system. Intake, exhaust and tailpipes. At some point, more power gains can only be achieved by work in the heads, to improve airflow through the cylinders. It get to be a giant snowball; but it can be a really fun snowball, with lots of power, smoking tires, noise,....

[Beancounter25]

Both Mikestang and Photog bring a valid point so I sent Doug Thorley this question.

"A question has come up - some folks are questioning the gains in HP and torque.
It appears according to the dyno spreadsheet that the vehicle tested had a catback before the header was put on and after the header was put on. Do the headers need to have a catback to realize those gains or can those gains be attained without a catback?"

We will see what their response is, I don't know, but I have a feeling you need to have a catback to realize those gains.

Thanks,
Brad

[Beancounter25]

Reply from Nick, a sales rep. at Doug Thorley Headers;

"Similar results will be had without a catback. I didn't even notice that.

Nick"

Interesting!

[bulldog]

What Tundra was used for the dyno? The 4.7, or 4.7 VVTi or the 5.7?

Are the headers for the VVTi ot the older V8? Thus 03-04 or 05+, or will it work on both?

I might consider it, but first need to figure out the horrible 2 into 1 exhaust y pipe on the 03-04 V8. Also need a better muffler.

[expat]

Originally Posted by Beancounter25

Reply from Nick, a sales rep. at Doug Thorley Headers;

"I didn't even notice that.

Nick"

LOL This is their area of expertise and he didn't even notice it.

Personally I'd like to see a true dyno report (although I know that wilol be out of the question) for each item (heads, cat back) by an independant dyno specialist. There you get to see all the details - multiple pulls, temperature variations etc.

Personally I don't think I'd be going down the road of headers on my truck but I am very interested to see where this goes. I could see a time when my engine needs to be rebuilt where I might want to put on headers...

[Beancounter25]

1. Bulldog, I emailed your questions and await the answers;

2. C'mon Mark, get the headers now. If we don't get to at least 20, you probably won't have the option of headers on your rebuild LOL!

[Beancounter25]

Bulldog:

"The year break for tundra's is 00-04, 05-06,07-09 for the 4.7. The one
tested for the dyno was the 07-09 4.7 vvti as all of them were the vvti.

Nick"

[expat]

Originally Posted by Beancounter25

1. Bulldog, I emailed your questions and await the answers;

2. C'mon Mark, get the headers now. If we don't get to at least 20, you probably won't have the option of headers on your rebuild LOL!

Honestly, I probably would if money wasn't an issue. Plus I got a bunch of other mods to do before headers.

[Mikestang]

Originally Posted by Beancounter25

Mikestang,

It seems that while the company has provided a dyno sheet that supports their gains, you doubt the gains could be that great. Should I take that as meaning you’re not interested in purchasing these headers?

Thanks,
Brad

I'll be following along, but not interested at this time. Thanks for pioneering this, though.

[Beancounter25]

Originally Posted by expat

Honestly, I probably would if money wasn't an issue.

Trust me, I know the feeling.....

[Beancounter25]

Originally Posted by Mikestang

I'll be following along, but not interested at this time. Thanks for pioneering this, though.

Not a problem. I'm glad to meet some new people!

[Blowout]

I agree with Bulldog's earlier comment that the Y needs to be resolved as well if your going to go to this level of effort.

Someone needs to come out with separated pipes to the rear bumper

[Beancounter25]

I can agree with both of you! To have the "Y" problem fixed, the guy putting mine on almost doubled his price for installation....that was a "YIKES" moment! The rest of the story is that I had Tundra headers and he couldn't get them on anyway and I was still charged for 1/2 the job!

My wife went to pick the car up from the garage and I would have paid the other 1/2 if I could have been a fly on the wall when she got the bill for what turned out to be nothing done - she's an excitable red head! LOL!!

[Blowout]

Originally Posted by Beancounter25

I can agree with both of you! To have the "Y" problem fixed, the guy putting mine on almost doubled his price for installation....that was a "YIKES" moment! The rest of the story is that I had Tundra headers and he couldn't get them on anyway and I was still charged for 1/2 the job!


My wife went to pick the car up from the garage and I would have paid the other 1/2 if I could have been a fly on the wall when she got the bill for what turned out to be nothing done - she's an excitable red head! LOL!!

How much did they quote you for the dual pipes to the rear?

I agree you would not want to be visable in that situation