Rich Ellis’ 1600 Supersport upgrade page!

The below article describes how I upgraded my Caterham 1600K supersport with 6-speed box. I unfortunately have succumbed to the dreaded upgrade-itus for which I have been told there is no cure.

My mechanical knowledge before the se7en was minimal and ranged from filling the washer bottle to signing the VISA slip for a service. I wanted more power but did not have the confidence to do the work myself. I hope that after reading the info below that some of you will choose to become more involved.

I initially started my quest by contacting Minister race engines and QED. QED only work on engines out of the chassis that would have involved me removing the engine, this was all to much to comprehend at this stage. QED also do a ‘bolt on’ upgrade that would advance power to about 150 BHP, this consists of ECU and throttle bodies (TBs) etc. Having already 135 BHP I wanted more than 150BHP so I tried Minister next. Off the top of my head I was quoted around 3K to convert the engine to 1800 with a new ECU, this again would have given around 150 BHP but with an increased torque curve. Their quote included removal and fitting and but not VAT. The price was negotiated as a one off about 18 months ago and you would have to approach Minister for an up to date quote. Again I thought this was only a small increase in power. I briefly looked at upgrading to an SLR but did not have an additional 10K that was needed. This left me in the wilderness and reading about people’s power output on Blatchat did not help.

I then happened to read a thread that had a link to Dave Andrews site and it’s wealth of information. If you have not visited his site then stop reading now and go visit. Dave is known as Oily on blatchat and I dropped him an email asking for advice etc. His reply got me very excited and made my bank manger weep. I will summarise the costs later but for around £3K 180BHP was on the cards. My upgrade-itus was now feeling better but other people said I only feeding it, which ends up making it worse. More on this later.

A trip over to Dave’s to look at some work in progress followed. Dave is a sound guy who speaks his mind but is willing to explain from first principles. Having decided on a spec, or more importantly how much money I could spare, I decided that Dave would port the head but I would help with installation. This was the introduction into engines that I was look for. Dave is very busy with all the K-series’ that he is porting and there was about 20-30 heads there in various states when I visited. My upgrade should have been completed by then end of June but had become delayed. In the mean time I went to Emerald to pick up an ECU and have a power run. Peak BHP was 134 at 6750rpm. Peak torque was 114 ft/lb at 5250rpm.

In mid July the upgrade had not been done and upgraditus returned. The extra time that I had, along with the argument to my long-suffering girlfriend that I can sell the super sport kit (This is for sale please contact me if interested) to pay for my next fix, had resulted in specifying some forged pistons and wilder cams. Thus my spec is now forged pistons, large valve ported standard head, 1227 race cams, direct to head throttle bodies, vernier pulleys, Emerald ECU and Bernard Scouse airbox kit. More information on all of these can be found on Dave’s pages.

I choose to go with forged pistons because the standard piston has been known to fail at high rpm. The supersport limit of 7600rpm has caused piston damage and although I do not habitually rev the engine at present I have been told that this will change. I currently drive between 3000 and 6000 rpm, and if you look at the power curve, this is where the max torque is. When the upgrade is complete the peak torque will be higher in the rev range (6000-7000rpm). The forged pistons will also allow me to rev to 8000 rpm with greater piece of mind. This should produce 190BHP plus from 1600cc. David Jackson has run an engine of this spec that produces 206 BHP. I will be happy with anything above 190BHP but will post my power figures when completed.

By August Dave had ported the head and I have fitted the forged pistons to a spare set of rods. To fit the pistons the bottom end needs to be rebuilt, in order to do this you need to get a reference number from the crank that tells you what big end shells to use, this took me a good 4 hours to get. The sump was a pain to remove but straight forward, the problems I had were mainly that some of the sump bolts had almost seized. When the sump was removed the windage plate was visible, this holds the foam baffles in place. The reference BAAA is located on the last crank counter weight nearest to the flywheel.

Every crank reference can vary so it does need to be found in order to have the correct shells. If I was to do the job again knowing what to do and where to look it would only take 60 minutes and that would include an oil change as well.

The forged pistons look fantastic and they have more pronounced value pockets – see the main K tuning page for pictures of these great looking items!

You can’t really see it but I had a casting pin that was raised about 5-6 mm right in the middle of the under side of the piston, this stopped the standard rod from fitting. Dave had to fettle this away before the rod could be used. What pisses me off is that these pistons are sold for use with standard rods, that supplied in this form is not possible. It is worth noting that if these are bought from QED then they need to be supplied minus and casting pins. It only took Dave 5 minutes per piston to remove but I had spent 10 minutes heating up the rod before hand. I also had let loose Sue, my partner, with the credit card in Milton Keynes, so this needed to be done ASAP.

The piston is connected to the rod using an interference fit, the same used on the VHPD. The fitting of these requires 2 sets of hands. Once the casting pin had been removed from the piston the rod pin was put in the freezer and the end of the rod heated with a heat gun. The pin was paced in the piston with the help of a large hammer. The fit is good for about 2.5 – 3 tons of pressure. To fit the rods to the pistons took about 2 hours in total.

The induction has been changed from plenum chamber to TBs. The main advantage here is that you go from 1 x 60mm opening to 4 x 42mm openings, thus much more air flow. These are supplied from QED but are made by Jenvey. (You can now also get them from Emerald or DVA). As I understand it, it would be a worthwhile upgrade moving from the plenum chamber to TBs without the head being removed. To do this you would need an ECU and airbox kit but should generate approximately 150 BHP for a smaller investment £2100 fitted as started on DVA site 11-02. This includes a RR session.

The throttle bodies are direct to head throttle bodies so there is no need for an addition-mounting bracket thus saving money.

The fitting was planned for 8^th and 9^th of August 2002 and I arrived at about 8:30am. The car was left for 30 minutes to cool down. I have driven from Oxford to Milton Keynes so all temperatures were at operating levels.

The water was drained first, followed by removal of cam cover, plenum and head.

If I had just opted for a ported head and new cams then it would have been rebuild time but the pistons had to come out next. The oil was drained and the sump removed. The foam windage plate, foam baffle and oil gallery removed. All this sounds complicated but is quite straight forward. The big ends and pistons were then removed.

It was here that I was relieved that I had opted for forged pistons. Removing the big end shells produced a shell that was living on borrowed time. Basically the engine could have gone bang at any minute. If I had just had the head replaced this would have certainly destructed the engine in the very near future. Below is a picture of my close call.

Four of the shells had signs of damage but this was by far the worse. I do not want to scare you but this engine had only done 7000 miles and 1 track day to produce this damage. An Apollo tank or dry sump is definitely advisable. I did had an Apollo fitted when I did the track day but this was removed for other reasons. The crank was then carefully inspected for any damaged but luckily there was none.

All the bad news was out of the way now and the liners were removed and replaced by a freshly honed set. The honing removes any marks or light scratches and produces a low grit (320) finish to help bed the new pistons. The pistons were then placed in there new home.

Meticulous attention had to be paid when the replacing the crank-rod bearings so that no dirt could damage either. Any grit may lead to damage as above.

The oil gallery, foam baffle and sump were replaced and the fettled head fitted. The 10 engine rods were then torques up to 15 ft/lb and a further 180 degrees * 2 rotations performed. The cams were then timed with the aid of Verniers. The approximate timing of cams is very well described on DVA pages.

Above you can see the difference between the standard head on the right and the fettled head. One is an inlet and the other an outlet but it illustrates the point. The port has been enlarged to an oval size and the inner fin greatly reduced. The surface has also been smoothed from a bare casting to a flat surface.

Since the Emerald users the standard wiring loom all the wiring was in place and just needed plugging in. The fuel rail and injectors from the plenum were retained but reversed so that the fuel feed clears the TBs. I had to extend the fuel rail length to avoid a kink in the line. This was cheaply done £10 by a local hydraulic shop for cash in hand.

The finished article! Here you can see the TBs and air box. Note the air box does not need a cut out in the bonnet.

I ran the car in for 1000 miles slowly increasing the rpm. It was evident that there was more power but the car sometimes hesitated when the throttle was floored or when changing gear on full throttle changes. Julian changed to the emerald ECU at the same time and was also experiencing the same problems. A quick call to emerald confirmed that this was a mapping issue and would be sorted out on the rolling road.

I had a problem about a week before the rolling road in that the oil pressure was dropping from about 6000 rpm up. I would get to about 6750 rpm and the pressure would drop to about 2 bar. I dare not rev the engine any further and the pressure would always return when the rpm dropped. The car was booked into RatRace for a check up and fitting of an Apollo tank. The oil pressure sender turned out to be at fault and the gauge was reading low. I did change the pressure sender about a month before the upgrade so thought that this would be working OK, I had changed oil filter, tried with more and less oil but without success. Everybody says that the oil pressure sender is very unreliable and this is yet another illustration of this.

I picked up the 7 the day before the rolling road and drove back to Oxford, the car was still running very rich but the oil pressure did not drop as the rpm increased. I managed to get home by about 7pm to find Julian waiting, we were sharing the next day at emerald, with his 7 wrapped up on a trailer. Shandyman comes to mind!!

We eventually found emerald, after 4 hours of travel, and both cars were mapped. Each car took about 4 hours but the results were well worth the wait. I have never been as nervous or seen Julian as nervous when sitting on the back of the cars being revved to 8000 rpm.

The vernier pullies gained me an extra 10 bhp as Dave Walkers adjusted them to correctly time the cams. The end result was 187 BHP at 7750rpm and 127 ft/lb at 6600 rpm.

I was at first a little disappointed with this as it had not reached it peak power before 8000 rpm but I do not have a dip in the power at 4500-5000 rpm which is typical for this state of tune.. I have looked at the same engine spec with 740 cams (slightly tamer) but I have more power through out the rev range. I must also remember that when I eventually move to 1800cc then the peak power will move down the rev range.

The car remains very drivable behaving like the supersport up to about 4500 rpm but it is louder and more throaty. The throttle bodies give the car a much improved throttle response and add to the character of the car. From 4500-6000 rpm the car becomes very much more responsive and the back end starts to squat down. From 6000-8200 rpm it goes like a scolded cat. This makes over taking very easy with the smallest gaps presenting opportunities. I recently attended a track day and the difference was very noticeable, the old car started to run out of breath from 7200 rpm up and it was not worth pushing any harder, now the revs keep rising all the way to 8200 rpm where the car is pulling very strongly.

MPG is still good with 30-35 mpg general driving however this does drop when further up the rev range, but I did not make the changes for fuel economy. If you would like to discuss any of the above or have any questions please feel free to contact me mailto:richard@raellis.co.uk

All in I have spent in total £4500 for the above changes. £500 was the investigation and fitment of the Apollo oil tank from Ratrace. The extra spend for forged pistons and fitting represents about £750. The total cost, if I had not run into problems with the oil, would have worked out at about £3250 for 180 BHP. Was it worth it? Well £4500 represents a lot of track days and would have allowed for other changes to the car, but at the end of the day I would still have seen SLRs fly past me and the engine would have eventually needed attention.

My own personal situation? It was very worth it with the condition of the number 1 bearing. It would have let go in the near future and I would have been looking at a new engine or rebuild. I would then have spent a large chunk of the upgrade money getting the car up and running again. If I had spent the money on trackdays etc. the car would now be in bits in the garage while I saved up the money.

I hope that you have found the article interesting and informative.