O Racer

Wayne, How long and what is the diameter of the two mufflers? Are they round or oval? Thanks John

My new race engine is ready to go to the dyno and I have to provide an exhaust system for the dyno test that I will later fit to the car. The header is the factory Caterham 4 - 1 stainless steel unit with a 2 inch outlet at the collector. It will be used mostly for track days and I am trying to balance maximum power with the need to not exceed 92 db sound limit at tracks like Laguna. I will have the exhaust pipe exit in front of the wing with a tip facing outwards...away from sound pick up which is on the other side of the track. I have been looking on line at Super Trapp, Burns, Magnaflow and Flowmaster. I would hate to spend $400 on a muffler only to be black flagged at my first event. I am sure I am not the only one to have this dilemma, any suggestions for an exhaust that worked for you? Thanks John

Hi Dave, Boy do I remember splitting time with college and racing but for me that was 47 years ago. College was engineering and the race car was a Buy Eye that I built, modest at first then as time past after graduation it was quite a contender. Congratulations on getting married, I met mine 45 years ago and she never says no about my car hobby then again I never say no about her horse hobby either! My Caterham Seven I bought new as a kit in 1991, built it myself and have driven it on the street and track days in its stock form up until now. I took it apart earlier this year and decided to take it to another level. The engine is bored to 84mm (about 1725cc) running CP Forged pistons, 12:1 C.R., roller rockers, big valves, A6 cam, SCCA crank, lightened flywheel, race/rally clutch, dry sump, 4-1 Caterham competition header, Pertronix Distributor and 45 mm Webers. I was going to build it myself with the help of a friend but decided to let a pro finish and dyno it and treat myself. I am excited to get it finished and the car back on track early next year. Although retired, seems it takes me much longer but at the same time I enjoy the process. I will post my results after dyno and in the spring, I will see if I can beat my 1:49 time at Laguna. John

Hello Dave, I just picked up with this thread and wonder 3 years later how the engine build went. It seems my reason for staying with the cross flow and not updating was like yours. Also our choice of build with A6 cam, SCCA crank and other bits. My engine with similar spec is almost ready for the dyno. I am wondering how yours turned out, what kind of HP and torque and driveability. Can you still drive out on the street? Have you changed anything since? Thanks John

KitCat We can only get 91 Octane at the pump but after the dyno run we will determine the best fuel, likely 110 for the track. I figure to keep a 55 gallon drum in my shop for the Seven. Mountain runs in my Seven will be limited to climbs to the summit and then back, due to the fuel range and to some degree the wear and tear on the driver. I have an Elise for more adventurous runs. The ultimate Elise drive is a lap of summit passes (there are 4) which I have yet to do but is on the bucket list. Start on Sonora Pass (CA 108) over the summit then down to CA 395. Take 395 north to Ebetts pass (CA 4) or south to Tioga pass (CA 120) back over the mountain, then CA 49 south or north back home. CA49 on the Western slope and CA 395 on the Eastern slope connect all 4 passes. All roads are well marked and maintained, have passing lanes and turnouts. California may have regulations that are a burden on car owners and make them expensive to operate, but we do have some great driving and scenic roadways. Thanks everyone for your feedback...when my Seven is back on road again I will send some photos, feedback on the build and dyno results. Also...after seeing the photo of Steve's car I need to spend a few days polishing the body which still won't look anywhere as nice as his car, amazing!

Thanks both Steve and Dave for the helpful information and photos. All my parts are Caterham including the header which I got from Caterham, UK. Steve, I assume your individual pipes are one piece with heat coating inside and decorative chrome plating outside the body. Does the alternator hold up to the heat with the header pipe so close? I have a fiber heat shield over mine that will likely need to be removed Steve, my builder targeted 150 HP and 135-140 lbs of torque which I would be happy with, perhaps we are a little conservative in the estimate. I will share the results after the dyno day. Thanks again for the help, this is going to be fun. John

Martin...don't know how to send a PM email... jgrosseto at iCloud dot com Thanks John

KitCat Off topic but...I live in the Gold Country on the Western slopes of the Sierra Nevada range at about 2,500' elevation. Turning left I climb to the pass at 9200' and then down the Eastern slope to 4,000' elevation. There's a 'T' at the end, turn around and the same unencumbered road home. As long as you don't do something foolish, the CHP leave you alone, especially if you are a senior. 5mph over the 55mph speed limit, try not to slow for any turn although hairpins are a bit more tricky. It took me 40 years to get out of suburbia and now I am in driving mecca When the engine is dynoed, I will post full build specs and dyno results. I could have gone Zetec or some other more modern engine, but somehow I just felt the Ford crossflow was right for the car...and for me. In spring I should be back on track hoping to take a few seconds off my lap time at Laguna and Sears This is a great site, I am thankful for the interaction from like minded car loving people. John

Steve, That would be great. I do appreciate it. I do have questions... Did your car come with the 4 - 1 or did you convert it from the 4-2-1 header? What is the year of your chassis? Mine is a 1991 with the long cockpit feature. Can you fit each individual pipe with the steering column in place or do you have to pull it and (hopefully) thread it back in place though the bundle of pipes without fouling Does your car have the diagonal cross member from the upper and lower chassis 'rails'? Can you take a photo from both inside and outside? Can you mark with tape on the outside where the chassis members are so I can get an idea on how to enlarge the hole without going too big and making a mess. In light of Tom's comments, how do you find the 4-1 header work with your engine...or better yet, what is the build out? My engine...45mm Webers, largest valves, roller rockers, A6 cam, 84mm CP pistons, 11.75:1 CR, Dry sump, new Scat Crank, lightened rods Engine is going together now, soon to be dynoed. Thanks Tom, John

Tom, Thanks for the thoughtful comments. The engine build is less 'mild' than I alluded to, it's actually close to full race and the car will remain a track day car other than some driving in the rural area around my shop. If I turn left and go up the Sierras, there is not a stop all the way to Nevada. Caterham does say it's the right part but until I start fitting each pipe and trimming the panel, it is still a concern. Any help from KitCat or other Seven owner that has made this modification is much appreciated. Tom, photo is my car at Laguna, your car looks pretty radical, I have never seen such a large wheel/tire combination. Is it set up for road race, auto cross...or? Thanks, John

Hi All, I am original owner of a 1991 Caterham 1700 Supersprint with a Ford Crossflow engine and Ford T9 5 speed, Car is left hand drive. The engine is almost finished with a mild race rebuild, part of the change was fitting a Caterham supplied 4-1 competition header in place of the 4-2-1 system that came with the kit. The 'bundle' of pipes exiting the body is significant, I realize the hole in the skin needs to be enlarged. There is also the steering column to deal with and a diagonal brace that seems to be at least partially in the way. Has anyone made this change and dealt with the modifications to make it all fit. Caterham UK says it will fit...LOL if it doesn't Appreciate any help or advise from the group. John

Dingo, yes, thanks so much for your reply and photo. Questions: Did your Seven come with the 4-1 header or did you fit it yourself? Do the four down pipes clear the diagonal chassis brace? Is the hole in the skin round, oblong or...? Two Photos of the pipes exiting the skin from inside and outside the body would help. Yes I am a BaT faithful for about 3 years, I comment when I think I have something to add and sometimes to voice my exasperation or frustration on a car or topic. If you want to go offsite, email me at jgrosseto at iCloud dot com. It would be easier for me to send photos. Thanks John

Thanks James and CASwede, I will take a photo and see if I can post it here. Never done that before.

Zona My posts were in advance of the engine installation which is very close now...I have yet to try to fit the header but recently I did a cardboard mock up of the engine in relation to the header exit hole which was not much help other to indicate the hole will need be elongated as the pipes exit the body diagonally. I have yet to determine if the chassis brace will clear the header. Can anyone provide a photo or two that shows the installation preferably one from inside the engine compartment. Thanks

Has anyone fitted a 4-1 Comp Header to a Seven like mine that was delivered with a 4-2-1 header? I am concerned that the diagonal chassis brace might interfere, anyone with experience with this? I have also looked online and could not even find an early 90's Seven with this header...Help!

I just bought a set from Dave Bean in San Andreas, CA

I am the original owner of a 1992 Caterham Super Sprint with 1700cc Crossflow engine, 5 speed transmnission and DeDion rear end, long cockpit version. It has been street driven and used in track days, more recently more track days than street travel, it has low mileage, around 12,000 miles last I looked. I am just finishing a major rebuild and upgrade to the engine: 45mm Webers, roller rockers, bigger valves, A6 Cam, CP forged pistons (84mm, 11.5:1 CR), SCAT Crank, lightened flywheel, dry sump and Comp 4 to 1 header. I have a couple questions now, maybe more later: RE: Header The original header was the 'stock' 4 - 2 - 1 header exiting the body on the drivers side. My new header is the Caterham part Comp 4 - 1 header with the collector outside the body. My question, does anyone know how much to enlarge the hole in the body, does the hole center stay concentric or is it offset in any direction? With the engine installed (not currently) fitting the pipes one at a time may not be obvious and enlarging the hole an exact science. Any help here or a way to figure it out. RE: Brake Pads The current pads are stock as delivered, any suggestions for a pad more suitable to track use? From what cars (make/model) did Caterham source the calipers from? Thanks for all your help and suggestions John

I have a bunch of cars, none have front plates, never got a ticket yet, if I do it is worth years of having no plates to ruin the look of a car

I track day my similar 7, mine a 91, my Kumho Victoracers finally gave up the ghost. I bit the bullet and went to Demon Tweeks and got a set of 185 55 14 Yoko Advan 048's, same tire that came on the Elise. Came to about $900 for 4 tires incl freight to the WC. Worth every penny Good luck

My 1991 Caterham Seven (Crossflow, T-9 5 Speed, DeDion Axle) 1700 Super Sprint still has the original brake pads, under 15,000 miles since build. Can anyone tell me from what car and model Caterham sourced the disc brakes so I can order a new set now the car is being used for track days? Thanks

Hi Dave I got answers for my questions: Tony Ingram suggests plugging the oil passage to the head (5/16 dia. stock) and drilling an 1/8" hole. That was for my engine build and maybe different for others. I am having the machine shop thread the passage and screw in an allen head plug drilled to an 1/8" He suggested not plugging the oiler in the connecting rod. I found out that Caterham UK sells a modified engine mount that allows you to plumb a five port dry sump pump without hose/fitting interference

Hi Kitcat. Right now it is a stock head that came with the 1700 modified Super Sprint engine package, with the larger valves and some porting in the head. The machine shop regularly works on Formula Ford and uprated Cortina engines so I will likely have them do some porting for the 45mm Webers and 4 to one exhaust, not sure yet. I will have the car on a dyno, will be glad (hopefully) to report great HP and torque figures but will be happy with what I get.

Hi All, I am building a track day race engine for my 1991 Caterham Seven with AX Block Ford engine, 5 speed with DeDion rear. I have some engine questions as the parts are ready to go to the machine shop: -I understand that you need to restrict the oil passage from the block to the head that lubricates the valve gear. The passage in the block is 5/16" in diameter. Any tips on how to restrict the flow, my idea was to thread the hole and screw in an allen head plug, drilled to the correct diameter...any suggestions on how much to restrict? -I also understand you should block off the small lubricating hole in the connecting rods, true? - When I mount my 5 port Titan Dry Sump Pump, will I have to modify the engine mount to clear intake oil hose and fitting on the pump? Engine details...roller rockers, HD springs, cam with 4,000- 8,000 rpm range, 11.5:1 CR 84 mm CP forged pistons, lightened rods, new SCCA SCAT crank, lightened flywheel, dry sump, 4 to 1 exhaust

Hi All, I am finishing up on a rebuild and competition upgrade to my 1991 Caterham with 1700 AX block Super Sprint engine with DeDion rear, left hand drive, a car I built and have owned since new. I have been trying to source a 4 to 1 competition header (1 1/2" primaries, 2" collector) from the US new or used to no avail and just got a price of 765 pounds from Caterham for a new one. Trying to come to grips with that cost, any ideas on where another might be available? Also wanting to buy four new Panasport light weight racing wheels and understand the the US dealer is having trouble getting new ones from Japan. I am looking for 6" or 7" wide 13" diameter wheels (Panasport or other lightweight) with 4 by 4 1/4" pattern with 4" back space. Any help or ideas, new or used?

Thanks Ross and My Seven. There is an amazing resource of information on USA7's