For me it really comes down to peak HP and a performance increase 5k to redline or a HP and Torque increase from 2k to redline with equal or higher peak numbers. I believe I'm going to add a little weight.

 

Another question: With the true dual systems on a relatively stock car, there is a documented power gain in the upper revs but is there loss of low end torque? Is it better to stick to a single exhaust like the factory one? I have tried searching about this but cant find any information.

 

Good questions and it depends on the system you choose. You have to look at the dynos.

The Fast Intentions system, on a stock car, looses bottom end up to 2200 RPM and fully recovers and gains at 2300. So you'll never really notice the loss. Others loose bottom end up through the low 3000 RPM range.

You also have to realize other mods you may make on the car - like CAI - long ones for sure - VS. short like Stillen - which is one of the best. I always go for function before form. Injen is a top winner in the function category when it comes to top end power - but you'll sacrifice a lot of bottom end to gain top end and leave the mid flat. Stillen wins all around.

You have to plan your whole car out - not just each step. You can't just choose an exhaust without knowing your intake mods or FI choices. Possible gearing options, etc. They all will take a part in how they affect each other in the end.

If you can't think that far ahead, plan for an exhaust that will help the whole power band. That will be good for all scenarios. True dual systems will fit that scenario best - testpipe help even more. TD systems will be the most versatile if any changes are needed are needed as well later on.

Rick

 

Thanks for the info Rick. Do you have any info on how much the low end loss is on a HKS Hi-Po? Also will a K&N/Ztube/MREV2 on the intake side lessen mitigate the loss with a true dual. Or keeping in mind the above mods, is it better to stick to a single like fuji, tanabe or stillen silver while gaining less in the upper rev compared to a dual, but not suffering low end loss?