75MM TB on a STOCK H.O.?

Topic: 75MM TB on a STOCK H.O.? (Read 5356 times) previous topic - next topic

75MM TB on a STOCK H.O.?

May 25, 2007, 03:10:39 PM

Only other upgrades were Exhaust, CAI, MAF, UD pulleys, and tuning the timing and fuel pressure. Gained 30 peak RWHP at 4700 RPM with a 43 RWHP gain at 5100 RPM's .

I always have been told 75MM TB is way too big for a stock engine, but these results seem to disagree.

75MM TB on a STOCK H.O.?

Reply #1 – May 25, 2007, 03:13:23 PM

It may be too big for a stock motor but since you're using the factory spacer plate (I'm assuming you are) and the factory intake manifold, it should balance out considering you are still essentially pushing air through a 60 mm opening.

Put a larger bore spacer and intake on there and then you'll see how it's too much.

Did you have it dynoed?

75MM TB on a STOCK H.O.?

Reply #2 – May 25, 2007, 03:13:51 PM

Its not my car, Here is a link to the article.

Link

75MM TB on a STOCK H.O.?

Reply #3 – May 25, 2007, 03:14:34 PM

They use a 75MM EGR plate too and grind out the stock intake opening.

75MM TB on a STOCK H.O.?

Reply #4 – May 25, 2007, 03:46:19 PM

WAYYYYYYYYYYYYYYYYYYYYYYY to big for a stock 5.0L.
What would be the benifit????

75MM TB on a STOCK H.O.?

Reply #5 – May 25, 2007, 04:04:01 PM

I think the only reason they saw so much gain was because they did all that other stuff at the same time. Hell, the UD pullies were probably worth 15 hp alone.

I doubt the huge TB helped all that much more.

75MM TB on a STOCK H.O.?

Reply #6 – May 25, 2007, 04:10:41 PM

I agree.The 75 is to big.I would bet if you pulled it off,installed a 60 or 65,it would be the same HP.If you install a larger than stock throttlebody,the hole in the intake needs to be opened as well,otherwise,it's totally defeating the purpose.

75MM TB on a STOCK H.O.?

Reply #7 – May 25, 2007, 04:26:47 PM

Quote

What would be the benifit????

Well i don't know you would have to ask them why they did it, but it obviously didn't hurt anything. I don't have any plans to put a 75MM TB on a stock H.O. I just found the article and thought it was interesting.

I will put on a 75MM TB when i install my TFS top end kit though.

75MM TB on a STOCK H.O.?

Reply #8 – May 25, 2007, 04:47:01 PM

I run a 70mm on my supercharged HO and it is plenty good for upto 500hp,stick with a 70mm you don't want to hurt low end torque.

75MM TB on a STOCK H.O.?

Reply #9 – May 25, 2007, 05:13:21 PM

I'm starting to disagree with that old assumption. Read why here: http://sbftech.com/index.php/topic,5732.0.html

More on this here: http://sbftech.com/index.php/topic,6484.0.html

75MM TB on a STOCK H.O.?

Reply #10 – May 25, 2007, 05:55:25 PM

Well before reading Paul's links, If you look at the dyno numbers it didn't hurt the low end torque numbers at all.

75MM TB on a STOCK H.O.?

Reply #11 – May 25, 2007, 06:02:21 PM

I don't understand how it could hurt low end torque anyway.
It will flow more air than necessary but the more air you can get in = more fuel you can add = more power. You cant hurt anything by having too much air in the cylinder. After all the engine is just a big air pump the more air in the more power it will make

75MM TB on a STOCK H.O.?

Reply #12 – May 25, 2007, 06:53:11 PM

it isn't only the AMOUNT of air you can get in, it is also the velocity, and if you hurt the velocity, you WILL lose bottem end torque. Dont belive me? Take a stock output 5.0L and add an open plenum 4bbl carb intake to it. now lets see how much fun it ISN"T cruising around town, with that intake over the stock one. Ask me how I know this.......

75MM TB on a STOCK H.O.?

Reply #13 – May 25, 2007, 06:56:34 PM

Quote

You cant hurt anything by having too much air in the cylinder

True to a certain point. Running big heads with something like 14 pound injectors at stock pressure may be an issue though....

75MM TB on a STOCK H.O.?

Reply #14 – May 25, 2007, 07:03:20 PM

The more air you give it the more fuel it needs.Then you got to get rid of the result.Exhaust.