bigjweb

As a general rule of thumb your wastegate actuator should be able to hold boost pressure to about double what it's opening pressure is. IOW, if you a stock 10psi actuator it should be able to hold about 20psi. The problem is that on turbos with restrictive hotsides (small turbines or exhaust housings) you can easily run the turbine close to it's choke point during spool or approaching peak revs. Very high exhaust gas backpressure will 'help' the actuator bleed boost off by pushing on the gate. IOW you might have bled much of the boost pressure away from the actuator via the restrictor pill and solenoid, but boost won't rise any further because EGBP is pushing the wastegate open.

I've read about the double boost pressure rule before. Does this apply more as the engine gets closer to redline? And hold more true as a turbo increases in size?

The reason I ask is because I was able to hold 22psi with the stock VF40 actuator, but not as much to redline as a 1bar actuator. mweiner actually argued with me about not needing an upgraded actuator at my elevation (5280'). I tried explaining to him that the little actuator, having a small spring, just can't physically stay shut as the exhaust gasses pass by. However, after reading the double psi rule over and over, I wonder if other factors play into the accurateness of that rule since I was able to run more boost then 2.5 times the stock spring pressure (with an HTA68 on e85).

i went stage 2 with a BNR 16g turbo, FMIC, DW fuel pump, GoFastBits Manual boost control. Intake, pro road tune and up and down pipe and stock exhaust, just about 325, i could go for more but dont want to risk blowing the 5eat till i do the valve body upgrade.

Just out of curiosity, why'd you go with a manual boost controller over a 3port?

With all the 3ports available relatively cheap, I wonder why people still use the manual controllers

"Look, let me put it to you this way: the NFL all too often looks like a game between the Bloods and the Crips without any weapons. There, I said it."

--Rush Limbaugh, Jan. 19, 2007

Since the stupid gun quotes thread is dead. I'll post this here.

The answer to gun violence isn't more laws, the answer is more prayers

-Rick Perry

my mom and every other 50-60yr old woman i know says, 'just sayin' all the time. And i want to punch them in the face every time.

 

bigj, this is technically a vendor thread so please keep the unnecessary remarks out of it. If you have something to add or an inquiry you are more than welcome to post here, thanks.

Call it what you want, but in case you haven't noticed, this thread is not in the marketplace. Just sayin

What's bad is that the NFL has higher standards

I was going to do a George W. Bush quote, but there are so many good ones to choose from

I'll just give you guys the link - http://politicalhumor.about.com/od/bushquotes/a/dumbbushquotes.htm

Ok. Malcolm.

To offset the RW stuff posted by BDII, a Malcomb X quote:

 

“Don’t stick a knife in me ten inches, pull it out six, and tell me we’ve made progress.”

Malcomb?

We must question the story logic of having an all-knowing all-powerful God, who creates faulty Humans, and then blames them for his own mistakes

- Gene Roddenberry

I hope you didn't pay for that ticket. Take them to court and the judge will dismiss them, unless it was a school zone.

2 or 3 mph over, while petty, is still over the maximum speed limit. Everybody always says up to 5 over and your good, but I have yet to see that law.

So what's the deal with the 5mt clutch vs the 6mt clutch. I've mostly heard that you can't reuse it, but this thread over on NASIOC contradicts that.

http://forums.nasioc.com/forums/showthread.php?threadid=872902

We were discussing why it that cars running given power levels can get away with running smaller turbines and exhaust housings on e85 than those burning gasoline. The effects of high-octane / low-calorific-value fuels on CR, timing and boost are well-understood.

You were talking about this? - The smaller turbos reach their max efficiency sooner and therefore heat up quicker then larger turbos, but because ethanol burns cooler then gas, the air charge remains cooler and more dense which means more total air molecules.

e85 helps because the extra fluid obsorbs more combustion energy.

E85 works because it has a higher octane rating then regular 91 or 93 unleaded gas. Meaning that it resists pre-detonation (knock) better then pump gas. The need for more E85 then gas is only because E85 has a different Stoich then gasoline. Gas being 14.7 parts air to 1 part fuel, and E85 being 9.7 to 1.