-
Posts
9842 -
Joined
-
Last visited
-
Days Won
56
Content Type
Profiles
Forums
Blogs
Events
Gallery
Downloads
Store
Everything posted by johnc
-
Here in the US we can typically get header and exhaust tubing in wall thicknesses of .035", .049", and .063" in mild steel, stainless, nickel steel (Inconel), and titanium. A racing turbo exhuast manifold will typically be built using .063" stainless and .049" Inconel or titanium. A racing NA exhaust will typiclaly be built using .063" mild steel, .049" stainless, or .035" Inconel or titanium. The same thicknesses are typically used for a street exhaust and a tubing bender won't work bending thin wall exhaust tubing. The tubing will just kink or collapsed. Search for tubing bend suppliers in your part of the world. Here in the US typical sources are: http://www.burnsstainless.com/ http://www.spdexhaust.com/ http://www.summitracing.com/ And many, many others. 304 and 321 refer to the types of stainless steel. 304 is more common and 321 is stabilized with Columbium to reduce carbide precipitation.
-
Your budget, more then anything else, will determine your choice of materials. For example: A 1.75" OD u-bend in 304 stainless is typically 110% more expensive then a similar wall thickness mild steel u-bend. In 321 stainless its 185% more expensive then mild steel. If you go with Inconel, expect the same u-bend to be 310% more expensive then mild steel and if you're thinking about Titanium, well, you wouldn't be asking this question on this board. Material selection depends a great deal on intended use. A header for a NA street car can be made out of mild steel because street engines are only run at full throttle for very short periods of time. The same can be said for a turbo header on a street car. Adding a high temp coating (Jet Hot 2000, Swain) extends the service life of a mild steel part. For an engine that's run at full throttle a large part of its service life stainless steel and Inconel have better heat cycling properties then mild steel. They also have built in corrosion resistance but will expand and contract more then a mild steel header.
-
Betamotorsports, LLC as a sponsor of Jeremy and Mike's effort, ponied up the money and parts for one basic reason: Advertising. For about $750 Betamotorsports' stickers got in front of a national television audience. Granted, you really couldn't see them very well, but it was a start. Given that, what are the benefits to a sponsor of the HybridZ car?
-
Not sure what all the fuss is regarding triple SUs. L24 engines built to SCCA EP specs make 250 to 265 hp on slightly modified OEM dual SUs. As posted here many, many times before, the intake side of the L6 engine is not the restriction. BTW... I have a set of 50mm (2") SUs that I would be willing to sell for $450. I had plans for them but the plans changed.
-
Its just like checking any car before purchasing. Rust is the #1 concern. After you've checked for that and feel what's visible (+25% you can't see) is tolerable, then you go on and do a basic vehicle check. Also, look at the quality of the fabrication work and a big check for me is the wiring - how well its done and does every electrical thing work. Electrical is usually done last and in a hurry. If its done right then you know the builder probably did everything else right as well.
-
I was going to get a cool suit but was talked out of it by a pro who ran one. He said that when they work, they are great, but when you run out of the coolant the suit actually makes you hotter. I just stuck with my old routine of puring ice water down the front and back of the suit. I was getting hot, tired, and sloppy at the end of the race sessions so I slowed down a bit. Came in 3rd at Streets (I hate that track) and won at the Big Track. The Celicas are basically an ITA/ITB FWD car with pretty safe suspension tuning running on street performance tires. Spring rates are double the factory numbers, KYB shocks, 225/40-17 Bridgestone S03s on 7.5" wide rims. 190 hp and 2,400 lbs. Mid 1:40s at WSIR. They are safe, predictable, and reliable. Not super entertaining to drive but they reward a smooth technique and discourage sloppiness. Pretty much a perfect school car.
-
Sunday, Streets of Willow. 117 degrees with a 15 mph wind. Me wearing a black three layer SFI driving suit, Nomex underwear, helmet, gloves, shoes, and racing 9 other guys in identical Toyota Pro Celebrity Celicas in a 30 lap race. Monday, Willow Springs (Big Track). 105 degrees with a 25 mph wind. Me again wearing a black three layer SFI driving suit, Nomex underwear, helmet, gloves, shoes, and racing 4 other guys in identical Toyota Pro Celebrity Celicas in a 20 lap race. Tuesday, La Habra. 91 degrees and no wind. Me, sitting in my air conditioned shop office thinking about going into the shop and welding some patch panels on a 240Z.
-
IMHO, this chassis is junk. I would not use it as the starting point to build a car for myself or a customer. But, the decision is yours. If you decide not to build it, why don't you use it to learn how to weld? Also, carefully remove any good body panels and sell them on eBay. Right now good rocker panels and rear 1/4 panels are scarce.
-
I have and had some HF tools and generally they last a year or two. The most recent HF throw away was a 14" chop saw that lasted 11 months. In that time it would lose power as it got hotter and making mutilple cuts on 3" square tubing got to the point that the machine was just generating heat and noise. I threw it away and spent $175 on a nice Milwaulkee 14" chop saw. No problems cutting anything. It all depends on what you're willing to put up with to save money on tools. As I spend more and more time making a living fabricating things I find I have much less patience for tools that ask for lots of it.
-
You'll need to do basic troublshooting. Check all the ignition components and adjust the timing to factory specs. Make sure all the plug wires are good, check the plugs, etc. Go through the fuel system checking filters, the quality of the fuel, fuel pressures, etc. This is basic mechanics 101. Its not something we can really help with because we can't see or touch the car.
-
Best tool to cut patch repairs out with?
johnc replied to BlackBeaut's topic in Fabrication / Welding
Plasma cutter for big metal removal like complete floor pans and a 3" cut off wheel for just about everything else. I've got some pictures of the work I'm doing on a customer's 240Z rocker panels here: http://www.betamotorsports.com/services/RustRepair.html All done with a 3" cut off wheel. -
Interesting webpage on tubing sizes/strength
johnc replied to JMortensen's topic in Fabrication / Welding
My engineering friend is traveling around the country checking bridges. I don't know when he'll be able to answer my question. Regarding gusset metal thickness, I typiclaly make it the same or slightly less then the tube thickness. But, that's for a single, in-line gusset. If I did the double gusset on the sides I would use material that was half the thickness of the tube wall. -
Broken stub axle?
-
Brake Cooler Testing (i.e. what not to do)
johnc replied to jrd's topic in Brakes, Wheels, Suspension and Chassis
There's a lot of confusion regarding silicone brake fluid (DOT 5) and a new specification that's not silicone (DOT 5.1). As Jon said above, silicone based brake fluid is not for performance use. It boils easily and any water contamination ruins it. Stick with a good DOT 4 brake fluid. -
Brake Cooler Testing (i.e. what not to do)
johnc replied to jrd's topic in Brakes, Wheels, Suspension and Chassis
I typically throw away the rubber dust seals around the caliper piston and periodically remove the pistons and replace the actual piston seals every few months when racing. As John recommended, ATE Super Blue is great when doing a complete fluid replacement. The color makes it easy to know when you've flushed the old stuff out. Castrol SRF has the best wet boiling point but its stupid expensive. -
You're kind of in this no-man's-land regarding shock choices. Spring rates in the mid 200s are "in-between" a full track setup where the Konis/Bilstiens start working well and where the Tokicos stop working well. You can revalve the Konis/Bilstiens to get them to work at the spring rates you're selected. Talk with Koni and Bilstien directly and give them all the information you can about your car. They will make some recommendations and probably charge about $100 per shock.
-
You're kind of in this no-man's-land regarding shock choices. Spring rates in the mid 200s are "in-between" a full track setup where the Konis/Bilstiens start working well and where the Tokicos stop working well. You can revalve the Konis/Bilstiens to get them to work at the spring rates you're selected. Talk with Koni and Bilstien directly and give them all the information you can about your car. They will make some recommendations and probably charge about $100 per shock.
-
my new struts, what do you think?
johnc replied to datman's topic in Brakes, Wheels, Suspension and Chassis
Make sure your new strut slides down into the hole in the hub casting and is not just butt welded to the top of the original strut mounting. Weld it at the bottom and where it meets the casting. I built something similar when I ran the Penskes on the ROD and a we tested, with a hydraulic press, a couple different ways of mounting the strut tube to the hub casting. Butt welding the strut tube to the casting failed. -
If it goes away after then engine warms up, IMHO its not worth tearing the engine down to fix it. Just take it easy until the engine is up to temp. On the 3L I had that used JE forged pistons it slapped until the coolant temps reached 150. On my motorhome the 8.1L Vortec V8 slaps like crazy for about a minute after a cold startup.
-
Interesting webpage on tubing sizes/strength
johnc replied to JMortensen's topic in Fabrication / Welding
The gusseting info is interesting but I'm not sure how true it is. I would think that both types of gusseting create stress points. I"m going to refer the page to my mechanical engineering friend. -
Interesting webpage on tubing sizes/strength
johnc replied to JMortensen's topic in Fabrication / Welding
The SCCA rule mandating the same size tubing is section 18.6.B/C - "Minimum tubing sizes... for all required roll cage elements." Basically, if SCCA specifies an element in a roll cage, that element has to meet the minimum tubing size listed in 18.6. This includes the front and rear hoops, rear braces, diagonal brace, door bars, front down braces, and forward braces. Anything else that the builder adds can be made from whatever the builder wants, although sticking with DOM is a very, very good idea. Tech can, on their opinion, reject a cage that they consider unsafe.