Slomove

Yes, I have the same interest. Please keep the discussion public!!! As far as I know as Dunnell, Raceline and Kent offer cam upgrades and other goodies for the hydraulic lifter Zetecs. My engine has 45DCOE carbs and a Dunnell ECU and I am at a loss what would be best to achieve e.g. 180-200 bhp and what to avoid. Also if using one of these special camshafts what else needs to be done to the head, springs etc. Thanks, Gert Edited by - Slomove on 8 Oct 2003 03:32:40

Hi Ammo, did you ever get around to do the exhaust pressure measurements? Regards, Gert

Driving at Streets of Willow track days last weekend I noticed a large amount of oil spray mixed with a little fuel coming from the rear air filter of my Weber carbs, messing up the right rear wing and the passenger seat back. I am running a 2 liter Zetec and had only occasional dripping before when driving hard. Actually it never happens while road driving. As far as I can see it comes from the suction hose that ends in the air filter chamber and vents the crankcase as well as the fuel tank. I guess the idea is to rather burn excess atomized oil and fuel vapor in the engine instead of letting it go to the environment. The oil level was admittedly somewhat high measured in a Raceline wet sump with the stock dip stick. Otherwise the engine was running great. If it is only the sloshing in the fuel tank and the oil sump on the track that feeds undesired liquids into the air filter chamber I would just disconnect this suction hose for track driving. Does anybody know if that may have an ill effect on the engine? Or maybe another advice? Thanks, Gert

Sure you are not dripping some expanding coolant on the exhaust headers? I had that smoking out of the gills and smelling.

Thanks Ammo, good recommendations. Some may go a little beyond my amateur skills and no, I don't have access to a rolling road. Actually, I am feeling quite lucky to have got my Weber carb setup running as good as it is now. That means probably a rather rich mixture . I agree with you and Peter on the general problem with the baffle thing. I am just not sure how bad it really is. Gert

Hi Peter, you are probably right. Probably I would not buy this one today anymore after going through a larger part of my novice learning curve (although it looks nice and has really fierce sound). Actually I bought it because it was advertised as "high flow" muffler whatever that means. Anyway, these doubts were the reason for my pressure measuring experiment and I would be interested to know what high quality "through-hole" mufflers with glass or stainless packing have as back pressure. If the difference is marginal I just keep the one I got. If the difference is significant, well, I just buy another one and fire up the MIG welder. Gert

Dave, according to what I read from these guys who did extensive dyno measurement, they could not prove in a single case that increasing back pressure behind the headers improved power. All provided the engine is optimally tuned. Ammo, I would be highly interested to see what you measure. And thanks for the calculation. I guess 6 HP would be acceptable/unavoidable. Maybe sometimes I look for a lonely road in the desert around here and try some accelerometer runs with and without the muffler. Gert

Since I installed the side exit exhaust a few months ago I was wondering if, besides good look and less cockpit smell, there might be a performance impact. The muffler I have now is of the baffled type without any packing. Very solid workmanship out of 304 SS, small and probably going to last forever without maintenance. Today I wanted to know, drilled a tiny hole in the header collector tube and measured the back pressure. That was quite interesting. At idle and lower speed there was nothing really to measure, i.e. less than 0.2 psi. I had to go to the freeway, floor the pedal at high revs to see some serious pressure. While somewhat difficult to sustain and watch within legal speed limits (plus somewhat) I reckon the back pressure went up to 6 maybe 7 psi at the redline. After reading information on other web sites that sounds somewhat high. Some guys measured a 10% power loss on the dyno at only 3-4 psi back pressure (with V8 engines). Anyway, I was wondering if other list members did some measurements or have an opinion what mufflers on Zetecs or similar 4-cylinder engines (160 bhp) should do. Is this pressure loss just the price for reasonable noise suppression (actually, my exhaust is not that quiet ) or should I consider changing the muffler. Of course I don't want a giant can dangling from the side of my car.... Gert Edited by - slomove on 29 Sep 2003 16:27:35

No, just using regular dust caps and except adjusting pressure before the session, no other change. Pressure held for weeks before and after this happening. Gert

I have Bridgestone S03 installed (btw very satisfied) 195/50-15 on 6"rims. At the last track day (actually my first track day ) i was running them at 18psi. After one of the track sessions I noticed total pressure loss on the right front tire. However, no leak, pumped up again and is holding since. I would suspect that I rolled the tires from the rim but I am not such a super hot driver and 18 psi doesn't sound too low either. Anybody has an explanation for that? The good news is that the Bridgestones are not grinding on the rim and drive reasonably well even with no pressure at all. Spare tire seems to be kind of redundant. Gert

I read a post recently recommending the Cobra Roadster 7 seats. Supposedly made for Seven style cars. However, on the factory drawing the base is specified to be 445mm wide including the "ears" at the seating surface. Measuring my car I find only 400 mm between the tunnel and the cockpit wall. Did anybody who installed the seat run into a problem squeezing it in? Thanks, Gert

I had the same problem. Seems the low pressure in the cockpit due to air forced up by the windshield sucks exhaust fumes back in. It is better without side screens (and probably also with aeroscreens). I changed to a side exit exhaust and it was gone while driving. However, now I have exhaust fumes when stopped. So what, who wants to stand still in a Seven Gert

I made my own very slim brake light (11" long x 1/2" dia) with 30 superbright LED for the roll bar. Material was about $ 15. You can find pictures and a build decription here: (http://autos.groups.yahoo.com/group/birkinowners/files/CHMBL/). It's much brighter than usual LED brake lights so if you want to cut it down to 10 or 20 LED of the kind I used it is still pretty good. Warning: This is not a US DOT legal 3rd brake light because the effective lighted area is too small. For that you need to distribute the LEDs on 4.5 square inch (which defeats the purpose of having an unobtrusive assembly). I don't know what the rules are for UK. I am also not sure if the LED distributor (www.eled.com) ships to UK. But any red or hyper-orange LED with intensity > 5000 mcd is usable. Gert

I had a convex mirror for short while. attached to the windscreen. Actually quite nice in terms of overview of the scene. However, the convex optic moves the focus of your eyes closer to the mirror. That means if you need reading glasses (I have 2.0) you need them to see clearly in the convex mirror, very annoying. If you can read witout you should be O.K. Gert