Racintweek

i never mentioned a manifold design. i even said it doesnt matter what type of manifold. just as long as the WG and placement are correct is all that matters


a smaller turbine does make more mani pressure but if you have a WG that can release that excess pressure then you wont spike/choke the motor.

iceracercrx

Wastegate is a important part to the puzzle. But not God of the manifold design. Please do the math on a former F1 car. 1.3 liters at 16,000 rpm and then you will know why they had small turbos with big wastegates.

Randy
PS I have a mid size turbo, with a mid size wastegate, with a mid range manifold, and guess what, it makes middle horsepower.

Racintweek

i find it funny that some people think what makes a wastegate work and what it does isnt true



the 3 mechanical engineers that i work with are laughing right now

Tom-Guy

Placement is design.

You are spouting Luke's feed the wastegate stick the tiny turbine off to the side manifold theory.

Placement.


A smaller turbine needs more pressure to do the same amount of work as a larger turbine. The wastegate is going to do ---- all to relieve excess pressure... all it is going to do is maintain the needed amount of exhaust pressure to acheive target intake pressure... which, for a smaller turbine setup, is a higher manifold pressure than a larger, more efficient turbine would need. That higher exhaust pressure is a loss.

If the small wastegate big turbine setups can't get rid excess turbine pressure, do you know what happens? It's called boost creep. If the system doesn't boost creep, there is no wastegate problem.


I've had to tune and resort a couple cars for local MEs, on average they do shoddy work and don't know as much as they should. Engineering is 70% theory, which means a lot of engineers are real short on real-world experience to cockslap their theories. MEs are either idiots, talented with pen and paper, or ninjas. In my experience, 1 in 100 are ninjas, the rest I could do without.

0b00st0

That is not correct. F1 cars use HUGE wastegates and HUGE turbos. They used to be restricted to 2 psi of boost and had to rev to 18 grand to make the target 900 or so HP. A huge turbo is needed to flow enough for 900 HP. A HUGE wastegate is needed to bypass most of the exhaust energy since very little is being used across the turbine.

They couldn't keep the motors together long enough for a good race and it was pissing off the spectators, so they were allowed 6 psi of boost. Now they only needed to rev to 12k or so to make the same 900 HP. Now the motors last for mostly the whole season.

0b00st0

Just about everything you said right here is incorrect.

Peak power is not important. Domestics have proven that quite nicely by showing that the first 1/8th of the track is more important for low ETs than the last 1/8th. To get down the first half quickly, you need a responsive predictable torque curve, good traction, and the right amount of wheel spin.

Next, a large wastegate is worthless on a small turbo, especially with high boost. Most of the exhaust energy is going to be going through the turbine, NOT the WG.

Exhaust manifold pressure will always rise, because of the nature of compressors. To keep a constant pressure ratio, the compressor wheel MUST, I repeat MUST spin faster and faster. Look at a compressor graph. The speed lines take a dive down.

AND that last part you mentioned doesn't make a lick of sense unless you have a constant engine speed and a constant load. That will never happen throughout the RPM range.

iceracercrx

the 3 mechanical engineers that i work with are laughing right now

The 3 mechanical engineers that you work with are circle jerky right now, HAHAHHA
JD and I will agree 1 out of 100 are good the other 99 suck each others ***** during lunch.

losesomethinbra

Shiiit since when are mechanical engineers experts on turbo setups?

iceracercrx

The differences between most engineers and racers is,
1.Racer will always finsh the build sooner
2. Racer will always spend less money
3. Racer will always win!!!


Randy > doens't work with any engineers, I just want to clear that up, I work with racers
PS The above post of mine was meant to be a quote.

Racintweek

why cant engineers be racers??

our intake manifold is on the fastest pump gas 05+ mustang (supercharged 26psi, prototype mani made 80Whp)
and we have and still are designing parts for big manufacturers

Alba racing
turner motorsports
kooks custom headers (engineers are so dumb we give advice to a company thats been around since before most of us were born)