Havoc

guys I’m curious to what the limiting factor to running huge boost.

Assuming your boosted air isn’t super heated (eg upgraded turbo and IC)
you have a aftermarket ecu and is tunned perfectly (I know you cant but assume)
and you can get the fuel etc etc you need to maintain whatever Hp you get

what stops you from running xxx boost ?

I was under the impression that detonation is always the defining factor, so if you had everything tuned perfectly you should be able to run 20+ 30+ psi on a stock engine ?

and if its one of the engine internal components that is the restrictor can you please tell me what it is and why.

Thanks

Sideways7

iTrader: (7)

I don't know what the limiting factor is, but to get huge boost thats within the efficiency range of the turbo, you're gonna have to have a huge turbo that will have pretty bad lag. Just something to think about.

Havoc

good point, but Im stil more interested in whats the limiting factor assuming you can get the boost

RandomHero

iTrader: (2)

Lets put a hypothetical situation together. Lets say you had a turbo that could produce infinate boost and still be within its efficientcy range (yeah right), and you were running a fuel with an infinate octane rating, and you had infinate spark to ignite this infinately dense mixture. The limiting factor would come down to just how much pressure the combustion chamber could endure before either the apex seals blew out, or the housings themself came apart.

bigdongsr94

i believe the s4 housings have a week point, on the s5 they made the housing have an extra angle piece on the housing insted of a 90 degree angle

Havoc

cool thanks for the input.

Im assuming its easier to overcome the spark related problems on a massive boost engine.
So fuel would be my limiting factor

so assuming perfect boost, and tuning and spark what max boost can you acheive on:

98 Ron fuel = xxx max boost
116 Ron fuel = xxx max. boost

or is it not as easy as that ??

KompressorLOgic

iTrader: (6)

you can actually go quite high on boost, if it was "perfect" ,i think ive heard of a car running over 40 psi before on normal apex seals,

however idealy this wont happen any SLIGHT SLIGHT detonation/impropertuning at all, would blow the housing in half or destroy the seals.

generally when running over like 20 psi, alot of people "dowel pin" the engine, which is reenforcing the motor alot so it wont break in half running that much boost or more. but in an ideal situation it wouldnt break in half.

RETed

We can't give you a solid answer on that question...

The problem is that there are too many variables to factor in.
There are "guidelines" that you can go by, but it still comes down to the abilities of the tuner and how aggressive they are willing to go (with the ignition timing).

Some people will tell you not to go over 15psi on "pump gas".
Some people will tell you not to go over 18psi on "pump gas".
Some people will tell you you can run up to 20psi on "pump gas".
So who is correct?


-Ted

Bukwild

I think with the advances as of late with water/meth injection you are going to see these old "myths" of 15/18/20 go away. I plan on running just water injection mixed with 93 pump and running 20lbs daily map. Now my fuel system is not up to par to run much more than this safely yet and that will probably run me another 2k just in pump upgrades and fuel fittings/lines. But I do plan to upgrade all that stuff this winter and maybe those numbers will look like high 20's on pump. I would not be suprised if a few forum members are running over 30lbs in a few months on water/meth/pump. We will see.

Havoc

Ted thanks for the input.

so 20psi is basically the max on a stock or modified engine, at that point it's going to come back to the tuning as the limiting factor.

kompressorlogic, I don’t believe dowels will help, their is enough documentation to make me think its more the tuner to weather you need them or not.

Bukwild, yeh I do agree

Cheers