Looking for some advice from those with more experience of the Renault scene. I am now looking at a number of simple upgrades to my 250 with a view to getting back into the sprints and possibly SLS after a year away post breaking the Impreza. Gave no illusions about being competative but will be more for fun and the buzz of competition. I had a Miltek cat back on the Clio 197 and the quality didn't look too bad. So looking at doing a sports cat back 3" deresinated system what areeoples advice re performance sound and quality of the likes of Miltek and Scorpion ? Will be doing this on a budget so top end systems are kind of out of the running. Was thinking of going CGR for the sports cat and then either Scorpion or Miltek for the cat back. May not be the right section but also looking for intercooler advice. Been looking at the airtec ones ? Anyone offer any advice on quality and performance and also which one to go for I.e Pros and cons of stage 1 v stage 2. I can't see a scenario where the car will be over 400hp so if the stage 1 is suitable there seems no point going bigger with the potentially bigger pressure drop associated with size but open to advice.
I wouldn’t bother with a cat back and just go for a mid box delete instead and save yourself a good few quid! And go for a stage 1 intercooler as they don’t block the radiator.
Thanks James I need to retain a cat for the regs of Road car classes and know from experience you can free up power and torque by freeing up the exhaust gas path so will be doing that regardless. I had seen somewhere that the stage 2 cooler sits high enough to encroach on the rad so the stage 1 was my initial thought.
I wouldn’t say they’re a waste of money but if you buy new they are pretty expensive. Cat backs I wouldn’t bother unless you’re going for huge power. You can get a pipe that replaces the restriction in the stock exhaust for £180 which is a lot cheaper than a cat back.
Thanks guys appreciate all the replies I like threads like this on forums as it opens debate and you can see the spread of people s opinions. Just a bit of back ground I am an aircraft engineer and have raced an Impreza for a lot of years and have built it from a bare shell up twice so do know a bit about cars and how to build a competative sprint/hillclimb car the limiting factor now is me lol age has caught up and my brain won't allow me to do the things I used to lol. Last year I took the decision to break the car and head in another direction. Anyway in terms of the exhaust I agree there is a definate cost v benefit here. The stock cat will produce a restriction right at the output of the turbine which will cause back pressure and ultimately affect performance, the same can be said for the exhaust but at the power levels I am looking at this would be to a far lesser extent. The other factor to consider is the assumption that as soon as you put a car on track noise is directly proportional to speed
Cat is definitely the biggest restriction then the stock flexi, although that isn't that restrictive. Full 3" system isn't really needed to make decent power. I'm stock exhaust and would see marginal gains having a bigger system. Plus they sound poor with a 3" [emoji38]
Thanks Jamie totally agree any idea what the standard exhaust is 2.5" or 2.75" I would guess. What intercoller are you using ?
Think it's just 2.5, my tuner told me to save my money and not bother and I trust his opinion. I'm on the smaller Airtec, more than upto the job and it has the most effective core in terms of cooling IATs
