2.7 dyno charts

Your making me want that header REAL BAD!

 

That's fine as long as you understand a header isn't magic. It's part of a combination of components all working together that make more gains than each individual component can make alone.

 

Thanks for explaining, i didnt know what displacement was, and thats also not that much diffrence from the 3.4, hopefully i can take my tax return from my wife and do the mods u did....and any luck on the intake manifold spacer? If it shows gains ill be down

 

Sorry, nothing yet on the spacer. However, I did get hold of a nice 2.7 manifold and gasket which will be used for the model, so everything's ready to go for making the test prototype. Right now, the CNC machinist is still working on another manifold project of mine.

 

I wish u the best on it, hope it can bring somethin up for these little engines

 

Thanks, man... so do I. I love driving my Taco every day and am willing to take on all the risk myself to find out if a spacer will work. It's really not a whole lot of money to design one part, have it machined, and tested. Doing it this way lets the actual dyno test results make the decision whether or not it's the right thing to do to offer it for sale to others.

 

Sorry to thread jack but man I could go for a Gear Vendors overdrive unit.

 

Displacement is just difference in cubic centimeters between the total volume of the cylinder chambers when all the pistons are at the bottom of their stroke and when they are all at the top.

3,400cc (or 3.4 liters) is 26% larger than a 2,700cc (2.7 liters) so it's naturally going to make more torque under the same conditions. Now some of that can be compensated for, but not usually all without having to resort to forced induction.

Outside of the Corvette engine 55 Chevy I had as a teenager (and motorcycles), I've always enjoyed driving underpowered economy vehicles and tinkering around looking for ways to improve them.

 

Wow... I never heard of this before.



Has anybody installed one their Tacoma? How many extra ratios do they get from it. My 2.7 already turns only 2,000 rpm @ 60mph on the freeway, and I'm not sure it could take advantage of any higher gearing or the extra weight. I'd love to put a 6 speed transmission in my truck, but reading about all the problems people have been having with it scares me off.

 

I decided to see what I could find related to weight of wheel/tire on dynos.

The first one that came out of the google box found quite a bit more than a small gain. Going from 72lb to 60lb showed a 10.82 hp gain.

http://www.audizine.com/forum/showt...cts-of-wheel-tire-weights-on-wheel-horsepower

Your alloy wheels and passenger tires must be quite a bit lighter than the 6-lug steel wheels and 245/75s on the pre-runner.

I would think their are other pre-runner vs 5-lug rotational mass differences that could reduce the rwhp on the pre-runner further.

Not trying to bash, but using the pre-runner dyno as your baseline doesn't seem appropriate.

Here is another dyno test on tire/wheel weight on motorcycles with the same results.

http://www.sportrider.com/tech/146_0406_motorcycle_dyno/

 

I don't have a Pre-runner, wad.

I have a base model 5 lug. The 16 inch wheels and large offroad tires that were put on the truck were not stock to begin with. The 235/60/16 configuration is very similar to the original 215/70/15 that it came equipped from the factory. The lower aspect ratio of the tires almost perfectly ( 1%) compensates for the slightly larger wheel size. Even the prerunner has standard 15x6 steel wheels which are smaller and lighter than the 16x7 Tundra steel wheels I had on my truck. This is why I think the wheels were only good for a few horsepower.

 

I believe worthy is saying that since your baseline run wasn't done with your truck, which has fairly light wheels and tires, but was based on a stock Pre-runner, which has fairly heavy wheels and tires, the hp gain from your engine mods may be overstated. If you had done a baseline run using your truck before engine mods, but with it's present lighter wheels and tires, then your stock truck would have made a good bit more hp than the Pre-runner did in it's dyno run. Meaning the header and intake might have had less of an impact than you think, and the wheels and tires more of an impact than originally thought.

I don't know if he's right as I haven't researched it, but I think that's what he's saying.

But regardless, you have a good map of where your truck is now, so you can show how much difference the intake spacer will make.

 

That's what I was trying to say.

 

If this is true... then the #1 high performance Tacoma modification is wheels and tires!

Seriously, wad made a fair point.
I just did some checking and the Prerunner came with 16x7 steel wheels and 245/75/16 tires, which was exactly what I had taken off of my truck except that the rims were Tundra steel wheels. So I already know that the weight difference is 15 pounds per wheel. This is assuming that the Prerunner tested had the stock steel wheels. If it had aftermarket alloy wheels, then the difference would be 9 pounds per wheel.

So the question now remains:

How much horsepower to the wheels is gained with a weight reduction of 15 pounds per wheel? I read that article that wad posted, and noted that the weight difference is half the total because only the rear wheels are turning the dyno drum.

So if a 12 pound reduction per wheel yields

+11hp/+11ftlbs

Then a 15 pound reduction should yield 25% more, or

+13.75hp/+13.75ftlbs.

Now if the Prerunner had alloy wheels, the weight reduction would be 9 pounds per wheel, or 25% less power, or

+8.25hp/+8.25ftlbs.

So does anyone here know what kind of wheels were on that URD Prerunner? That would narrow down the comparison.

So, assuming stock steel wheels were on the Prerunner, the gains would readjust from

+26hp/+19ftlbs

to

+15hp/+8ftlbs

Or if the Prerunner had alloys, it would be

+18hp/+11ftlbs

Yes.
That's what really matters.

There is almost a complete lack of any performance information on the 2.7. Those URD runs were the only pre-existing evidence, so I can only accurately quantify changes from the starting point that I created.

 

It would be interesting to get a couple of other folks with bone stock 5 lugs to do a dyno run to see what they come up with. If we could get 3 or 4 to do it, it would be interesting to see how much difference there is between them. I'm sure there is a chassis dyno somewhere around here in middle TN, I may have to see what it would cost to do that. Got me curious...

 

Ah yes, the old shoe boxes. I love 'em. Here's a pic of the '55 my brother and I built and raced in the late 70's, early 80's. This pic is circa 1981 at Bowling Green, KY. I believe when this pic was made it had a 461 ci big block/TH400 in it.



By 1985 it had morphed into this:

 

I don't think dynoing mine up at 5280 ft would tell us much.

Since we are talking racing now, my '70 Challenger Convertible with a healthy 360 has run a best of 15.0 @ 94 mph at Bandimere @ 5800 ft. Doesn't sound impressive but with the altitude adjusted that's a 14.1 @ 99.3. 3.23 gears and a rather mild stall converter are costing me at least a half second, but it cruises at 75 nicely.

4:11 and a gear vendor overdrive sound appealing but a tremec 5 speed is what I'm saving for.

 

You going to Bandimere to watch this weekend?

 

Na, done that a few times...... It's fucking HOT out there.

I run at the Mopar meet they have in May when it isn't sweltering.

 

Ah, Pick... that brings back "old guy" memories.

I had a 210 2 door sedan similar to yours, except it was a mild street car. Just a stock 1963 Corvette 327ci block and heads, with an Edelbrock high rise and Holly 3310 on it. Moved pretty good for its time. And my Sun tach was on the inside.