Yeah, it's called a hydro booster, they're mainly found on big trucks that need a heavy duty boost to the brakes and don't have suficient vacuum. I still prefer the vacuum boost system, personally. There's less that can go wrong, and there's a significant increase in brake booster failures when you move to a hydroboost system, I know mechanics who live and breath brake work who've only replaced one or two vacuum boosters over 15 or 20 years, and repaired 2 or 3 hydroboosters a year. Not a huge number, but when you take into account the number of hydroboost systems out there, it's pretty big.

 

SVT Cobra Mustang comes with them stock alonog with some years of Safaries. I have yet to come across one that has failed.

 

I'm not saying they fail often, just that they fail more often than vacuum systems do. Besides, I personally prefer the feel of the vacuum system over the hydraulic. Probably just because just about every car uses them, and I'm just used to it. In any case, though, there's ussualy alot less involved in putting a vacuum pump than a P/S based brake booster system.

 

On OEM and aftermarket power steering boosters, they feel the same as a vaccuum one. There is really a difference when you go from the upper powerband to the lower when there is an agressive can. I don't know how technical you are about a power budget for your electrical system, but when you're running a lower amperage under driven alternator.

 

Uncle bill - one of the best explainations of Octane rating i've ever read. i've tried to explain it to people and just couldn't get the concept across to them...

just a side question.. how (or does) alltitude effect the selection of octane to use at a specific compression ratio?
would you agree in general that a flat top piston provides a more uniform flame front and tends to require more octane or less octane?

FlufyTiger - my recommendation is to skip the cast and hyper and go for the forged. it has been my experence that sooner or later folks want more power out of a combination and will be limited by the earlier choices made...that high feeling after you nail it the first time wears off and then the need for more starts working on you..that blue botttle starts looking real good or you want that performance tune that gets you to much advance and then the piston starts rattling around in the bore and a skirt breaks off...

Greg

 

Why are you telling me that? I never even considered buying anything but forged. I didn't start the thread, and I wouldn't be the least bit surprised if the person who did isn't even reading it anymore, as long as it's been up here. As far as I'm concerned, anything I want to build will need the strength of forged iron or steel by the time I've got it where I want it, so cast or hypereutectic pistons aren't even considered plausible options.

 

I think there is a place for the hypereutectic pistons and it is related to cost more than anything else, a higher hp $$$ build its a easy decision but in a budget build you are taking about a $225 piston and compairing it to a $600 to $850 piston depending on brand that is a big difference If the rest of the engine isnt build for the N2O what is the point of spending more money on the forged pistons?

 

rat454
I've always said that the best domed piston has no dome at all. Of course, the flatter a piston is the better the flame will travel without disruption. If You most use a dome to get the needed compression, then hand shape the dome to remove any areas that will disrupt that flame travel. I've spent many, many hours shaping pistons for that purpose. On the altitude issue, it becomes more complicated. Of course, when You remove oxygen from the air, You must increase something else to compensate for it. In most cases increased octane will do. In the extreme, a Top Fuel dragster or funny car running on nitromethane must increase the oxygen through the addition of more compression ratio and turn the supercharger faster to keep the horsepower level to compete. I've seen as much as a 2 point compression increase ( Denver Race ) from about 8.5-1 to 10.5-1 to compress the less dense air. In the case of the average car, You cannot increase the compression so you live with the lessened horsepower. You don't have a supercharger to force air into the engine.

 

Well I looked up hupereutectic pistons on the internet to see what some machine shops thought of them and for the most part they say they are very nice pistons when it comes to resisting detination and can hold up to 500hp. By the way I was wanting to get the compression part straight so if I run 10.3.1 compression pistons with aluminum heads will I get 10.3.1 compression or 11.3.1? I was thinking it would be 11.3.1 and there is no way I want to run any higher than 10.5.1 compression on a daily driver.

Thx again for all of the imput.

 

The aluminium heads don't change the compression because they're alluminium, they change it because they have different combustion chamber sizes.