Tollerance in engines

[Ruathar]

I am hoping someone out there has some experience of this type of idea, but I am wondering if there is any sort of guide to the tollerance levels of components in engines with regards to increasing the power output.

e.g. if I have a 200bhp standard engine, how much could I tweak it before I start having to consider custom gaskets etc?

[nigelbread]

Unfortunately there is no formula.
All engines can be tuned but many have a very low % of power increase available.
It is best to look at the tuning been done by others e.g. cosworth and go by there experience.
If you have a particular engine in mind research that make, look for forums covering you chosen engine.
When you have built an engine to the recommended limit with all the trick parts the next stage is to see how far you can go before it explodes.
Cosworth experimented with the 2ltr ford pinto and had the engines blowing up on test rigs and discovered the blocks were twisting!
The classic is red top engines then tune a bit further.
If you have an autograss club in your area it is worth looking at their engines as most are tuned on a tight budget.
Nigel.