So you want to up the power of your Boxster/Cayman? In this blog post we are going to go into some detail on your options covering what the gains are versus what the cost is to try to help you decide on which route to your ultimate goal is best, we will also be outlining any other hidden positives/negatives that you may see with the mods. There will be no particular order to proceedings here but the title for each section will give you the headlines if you want to take the skim read approach!! This will only be covering bolt on mods that the keen DIYist can take on so no engine swaps or strip downs!
Intake
Minimum cost: £0
Maximum cost: £1500
Minimum gain: 0BHP
Maximum gain: 32BHP (Claimed)
Gain/£: £47 per BHP
Under this category we are including parts from the air filter to the inlet manifolds, the specific parts would be Air filter, Intake ducting and inlet plenum. Apart from our own Carbon plenum we only have the manufacturers claimed figures to go by, another consideration is that most of the claimed figures published are after a remap so the cost of that has been added to the Maximum cost above along with all the most expensive mods listed we could find on the market. The 0 cost would be for a simple de-snorkel where the opening is left uncovered, we recommend fitting some sort of guard to stop debris so the 0 cost is a little unfair, our grille cover is £26.50 but we have not back to back tested the desnorkel mod and we doubt there is any BHP gain worth noting. Other benefits of intake mods could be reduced weight and increased intake noise which is subjective as a benefit. There is not a great deal of weight to be saved on intake mods as the OEM parts are mostly plastic, we have weighed our full carbon inlet installation vs stock and ours is only a few grams lighter, an aluminium plenum kit will almost definitely be heavier than stock but not by much. We have had reports from customers that our carbon plenum has a louder and nicer sound than OEM, some will see that as a benefit whereas some will not, an aftermarket filter will generally give a louder induction noise as well.
Exhaust
Minimum cost: £200
Maximum cost: £4000
Minimum gain: 5BHP
Maximum gain: 25BHP (Claimed)
Gain/£: £160 per BHP
This was a bit of a minefield to put together as there are vast options available on the market, some very high end companies and some very low budget, that is the reason we have little interest in developing an exhaust here at MRN. Your options for your exhaust system are simply 3, option 1 being replacing manifolds (headers), option 2 to replace the rear section after the manifold and option 3 to replace both (the full system). In most cases there will be a weight reduction and an increase in noise but some reports of droning mean this can be quite undesirable, droning is when a resonance occurs in the exhaust system at a certain RPM, often at motorway speeds unfortunately and is not a pleasant sound at all. The marketplace for exhausts is vast and some caution should be used when making your selection as some reputable companies take a product from somewhere else (typically the far east) and simply rebrand it and add an extortionate mark up of sometimes up to 3 times the cost of the same part available elsewhere. Our advice is do your homework or contact us for advice, we are happy to advise even if we don't sell the parts.
Weight reduction
Minimum cost: £0
Maximum cost: £000's
Minimum gain: 1Kg
Maximum gain: 150Kg
Gain/£: £?? per Kg
Weight reduction is often overlooked when people are searching for ultimate performance in terms of acceleration/braking and cornering, a reduction in weight can be far more beneficial than a BHP gain as a BHP increase will only benefit acceleration/top speed. Lets look at some numbers in the simplest form to prove this, if we take the power and weight of a 987.1 Cayman S you end up with a BHP/Ton figure of 217. If we take the maximum (claimed) BHP gain from the Intake section above we get 241BHP/Ton. If we keep the same power as the stock car we can achieve the same power to weight ratio by removing 135Kg of weight. That sounds like a lot but if you remove all the carpets, sound proofing, stereo system and replace the OEM seats with bucket seats you will likely hit that figure and all you will have to buy is the seats which can easily be done for less than the full set of intake mods cost. Lets not forget you will get braking and cornering gains as well. As far as other weight reduction methods go, if your pockets are deep enough the sky is the limit. You can go for carbon fibre body panels, plastic windows, PCCB brakes, wheels etc but the deeper you go the cost per Kg gets less and less beneficial. Porsche did a pretty good job with our cars with the use of aluminium all over the car so after the big chunks have been found you are not going to get too far.
Forced induction
Minimum cost: £6500*
Maximum cost: £20000+
Minimum gain: 100BHP
Maximum gain: 250BHP
Gain/£: £43per BHP*
Now this is where things get interesting, without opening up the engine the maximum gains when tuning NA (Normally Aspirated) will be around 40BHP and to get that you will need to spend around £3000 on the full set of mods for your intake, exhaust and remap, even then a 40BHP increase is almost unheard of. If you want more than 350BHP from your 987 without opening up your engine then forced induction is where you need to be looking, it is also the best £/BHP by some margin. There are very few options available for forced induction on the 987 platform so we thought we'd better offer an alternative. Our twin turbo conversion will target a 150BHP increase with a target cost of £6500 which gives the £43/BHP figure above. We will follow up this blog post with some details of the development so keep watching!!!
*actual TT kit results and pricing of 177BHP gain vs £6995 current price mean a £/BHP of £38.5/BHP which is better than quoted above