pparaska

Lone, thanks. The only reason it's getting to me is because the shots are coming from someone I've counted as a friend. Thanks for the advice! I try to follow that often, and you really really need that point of view if you go over to Zcar.com!

Mike I can't blame you for being pissed. I have never seen anyone have as much trouble with a fuel system as you! No reflection on your abilities, I think there is some basic problem that's just hard as hell to find. I've been really liking what I've been reading here about TBI. The only thing I don't like is having to burn chips and not being able to laptop tune the thing. Can this be such a hard thing to come up with? I guess most of the aftermarket companies are concentrating their software engineering dollars on the dry manifold stuff. BTW, what about these new EFIs from Holley, Felpro, Edelbrock, Accel? Aren't these things fairly turn key (hey they all seem to need a bit of tuning, some more than others from what I've read). I know the good ones seem to be really pricey though. That'd keep me away for a while. Hoping my carb works o.k., Pete ------------------ Pete Paraska - 73 540Z - Marathon Z Project - pparaska@home.com">pparaska@home.com -

BLKMGK, not you. I was probably being too sensitive anyway. I like to use these forum to pass what I think is correct info, but I'm always open to correction if I'm wrong. I also use these forums to put out ideas to see if I'm on a good path or not with a problem or a theory, etc. It's just that some of the stuff I've been putting out lately is getting criticized out of hand (I feel anyway). I put it out there to get feed back, and I thought I made it pretty clear that I was just thinking out loud. I'll put those words in from now on, if I can remember to. No foul. Back to our regularly scheduled excellent technical discussions!

Mike, you've told me that about the ceramic coating making it seem like hood temps went UP after it was put on headers and that was the first I'd heard that. What gets me is that it's totally contradictory of the info the coaters advertise. I'm wondering about the variability of the coating thickness set to set and the effect of thickness on insulative properties. I'm stumped. The ceramic is supposed to insulate, but there isn't much that seems to be on coated headers. Plus a shiny AL surface shouldn't have much emissivity, and therefore shouldn't be an efficient radiant source even if the outer header surface did get hot. (I work with IR weenies these days, I'll be asking some questions. Seems IR is a great tool for telling where "bad things" in the sky are. ) I wonder what good if any one of those custom fit aluminzed heat blankets for block hugger headers would do. Since they fit loose, I'm wondering if that wouldn't be a good way to go to keep heat from radiating off the headers. I've been thinking about investing in an IR temp sensor gun with the laser pointer. This tool would help answer how hot the header surface really was, and if that head pipe under the starter is a problem. Plus you could use it to hunt for good camber settings at the track. Oh yeah. I've seen that passenger frame rail harness melt on an initial V8 startup. That's why mine is relocated up high on the fender well. I had to add a foot to about 8 wires to be able to do that, but no biggie. It's at least a foot from the headers everywhere but at the firewall. I'll take some picks of the engine compartment and put them on my site this weekend. Those muffin fans are sounding better all the time.

Al, I know this sounds like blasphemy, but a guy I know with little money has a V8 Z (JTR conversion) with big tires and flares, stock 240Z cut down springs (1 coil or so) and a 7/8" front sway bar. I think he has the old Kontrolle struts. I was amazed at how nice this car road and how flat it cornered. A very nice street ride, not too soft or too hard, and pretty darned flat throught the corners. So lowering springs (I'd go with Tokico/ST) and KYBs may not be a bad way to go. You can always add some of those cheesy looking rubber donuts under the lowering springs if it lowers it too much.

Good point. I heard it from Bob Worley that when he changed from stock isolators and lowering springs to camber plates and coilovers (after sectioning the strut tubes) that the ride actually go better. I may go to camber plates someday, but I'm going to try it with the stock isolators first.

My reason for 17s is the same as Mike Kelly's - tires just aren't available in 15 or 16 to do things anymore, or they won't be in just a few years. I came across a great package deal on wheels, tires, AZ Zcar brakes, stub axles, and custom CV shaft adapters from Jim Biondo when he was changing stuff on his car. Yeah, 17s have there drawbacks, but I decided to go for it due to the tire choice issue and I like the wheels and they are light and stiff. Yeah, Wilwood calipers don't have seals - big deal, I'll put less than 4000 miles on it a year (I live a mile from work and I will only ocassionally drive it there.) Throw the criticisms about my choices if you like, but like Lone said, I built it my way based on decisions on what made sense in many areas. Hell with a 10 year span of years for designing and building this car, lots of things have been done that I wish were different. Then again, I can always go back and change things I don't like. If the super cheap deal I got on the rad turns out to be wasted money because it overheats, big deal, I 'll put a Griffin in it and I'll have a BIG radiator AND a BIG fan. If the Tremec IS the notchy hunk of junk it's reputed to be, oh, well, I'll get a T-56. I'm not concerned. It's a living project. I'm just tired of getting pot shots about my choices lately guys, had to vent. Lone, I know you weren't taking one.

Ross, I never said anyone should try all this other stuff before trying the starter solenoid. I treat that as the first thing to do - I have one installed. Voltage drop from too small of a gage of battery cabling that is long from a relocated battery is the next thing. I was just looking for reasons that the starter gets so hot that it won't work, with sufficient voltage to it. In other words, fix the problem, don't band-aid the symptoms. Sure, a $10 solenoid is hardly a tough band-aid to apply, and if it helps alleviate the heat soak problem (it historically has) then it should be one of the first lines of defense. If the starter is not pulling in or cranking on heat soak, the first thing I would do is measue the voltage drop on both sides of the circuit, from the battery positive post to the starter (during starting) and from the negative post to the starter bolting area. This can show you whether you need to worry about the voltage drop and the need for larger cables. If you are droping more than a volt, it's something to consider. Most starter motors are designed to work at less than 12v for this reason. If it's a 12 V or so during cranking at the battery but 9 or 10 at the starter (across the body and the battery cable lug), your cabling is too small (assuming all the connections are good) or maybe you need a negative cable as well. Looking at the voltage drop on each side of the circuit (pos and neg) will tell you which is undersized, if any. Just for the heck of it I ran a 2 gage negative cable from the battery to the engine block near the starter, as well as grounding to the chassis at the battery. A steel frame or unibody is not the best conductor, so I gave it some help with a parallel cable connection. As far as the fan/rad not being able to keep up, if the car is overheating then yeah, you'd need to address those parts, etc. But if it's running 195 with a 195 stat for example, the heat from the engine will soak into the starter. After you turn the car off, there's a spike since the cooling system stops working and this heat goes out into the starter, etc. Adding more heat to it with a hot uninsulated pipe and headers near it doesn't help. I was just bring up the muffin fans as a way to get the heat out of the engine compartment right after turning it off. Of course, cracking the hood is probably even better, but I don't like the idea of walking away from my car with the hood unlatched.

quote: Originally posted by Andrew Bayley: Pete (and others): I guess one area to be suspecious would be the starter wrap. I could see how it would help keep heat out... but once heat found a way in there... wouldn't it also help contain the heat? Also, is the exhaust the only source of heat for the starter? I suspect the a good deal of heat is also being transferred through the engine block. Once the heat works it's way from the block into the starter, the heat shield/wrap might actually hold the heat inside the starter. I may be crazy, but has anyone else thought about this? Yeah, that's the same thing I was saying above your post. The starter gets hot by being bolted to the engine as well as radiant & convected heat from the exhaust system. Great (or not so great?) minds think alike

For a Carerra 8" free length 300 lb/in spring the stroke (how much it can be compressed from it's free length state) is 4.75". For a 200 lb/in 7" spring it's going to be only about 4" of stroke, so after using 3" of it to hold up the car, you only have 1" left for bump travel!

I'd suggest getting a few books. If you are talking about small block chevy's "how to Hotrod your small block Chevy" or something like that is a classic. Bill Jenkin's book is also good. OF course, GM's Chevrolet power manual is great, but focused on later designs. You can find these in Summit Racing or Jegs catalogs, as well as classic motorbooks.

Mike, I understand that an XX rate spring is just as stiff in an 7" free length as it is in an 8", or another free length spring, but the issue I was getting at was that if the car weighs 600 lb per corner, and you use up some of the spring's stroke with holding up the weight of the car at stand still, you only have the remaining stroke of the spring left to absorb bumps or take weight transfer onto before you get to no stroke left and coil bind. That's why I was told that for an 8" (2.5" ID) spring in the rear, less than about 275 lb/in would not be stiff enough, and you'd end up coil binding on large dips, etc. I hope that's wrong. I have 300 lb/in in the rear and I'd bet it will be too stiff to my liking. I'll do your coilover test when it gets on the road and see if I can go a good bit lower on the rate. As for why you don't think a car with 17" wheels needs shortened struts, I don't understand. I thought this was the preferred method of lowering the car, as lowering springs take away bump travel. I want to keep the stock 240Z isolators, so that takes that method of lowering the car away for my purposes. I guess I don't understand what wheel diameter has to do with whether you would want to section the struts or not. My car is unflared, with 17x9s (149mm backspacing, 1/2" thick Wilwood rortor hats) and 245/45-17 Michelin Pilots. I have the coilover tube situated so that it's at the top of the 1.5" shortened 240Z rear strut, placing the very bottom of the tube next to the rim lip. There's only 1/8" of clearance between them. Jim Biondo had this exact setup on his unflared car and he said the wheel never touched the tube. The wheels are very stiff. The tire clearance to the spring perch is about 3/16". Close, but it won't touch either according to Jim. I guess I need to take some pics of this. I tried before but had a hard time getting anything decent. I'll give it another shot. I hope you are right about the 300 lb/in springs not being able to give even 3" of bump. Because they compress about 2" with the weight of the car, I'd guess, and that would only leave 2.75" left for bump travel. The 300 lb/in 8" free length springs I have only have a 4.75" stroke.

Dean, Glad you joined the Forums! Welcome! For those of you that don't know, Dean has been running a V8Z for many years. Glad to have another member with experience on board!

Just wondering how many of you that are having heat soak problems are running block hugger headers that might be wrapped or ceramic coated, but have unwrapped/uncoated pipes that run from the headers back? I have a theory that running block huggers with an uninsulated head pipe might be causing the heat soak. Hot air would rise from the head pipe to the starter, as well as heat being radiated from the pipe to the starter. This is the reason that I had most of my exhaust system coated (until behind the diff anyway). I wanted to not heat soak the starter, not let the exhaust system contribute any more than needed to the under hood temp problem, and keep the floor boards/tunnel cool. (Well, it looks very nice also, and all my handy work of making a custom mandrel bent dual system won't be ruined by rust either.) It's still a theory since the car has not been started yet. Just wondering if it was worth trying to wrap the header pipes from the block huggers back even temporarily to see if I'm right on this one. I'm also a bit leary of the starter wrap. Fine for keeping heat out, but as the starter gets hot through conduction from the engine, I'd think it might hold heat in the starter/solenoid and aggravate heat soak. I think the best solution would be a good insulated starter heat shield that let air pass around the starter... I put the Moroso mini starter heat shield on my car. Nice design with insulation between two AL sheets. The problem I have with it is that it leaves the bottom of the starter open, to the heat radiated from the head pipes on block huggered engines or long tube headers. One thing I'm going to try to see if heat soak occurs is modify it by adding a section below the starter. But I hope the ceramic coating on the head pipe would keep the radiation from the pipe to the starter down. Underhood heat management really needs to be researched better on this swap. Did we come to the conclusion that a pan from the radiator to the front crossmember could help pull air out of the engine compartment to underneath the car at speed? Of course, that does nothing for the heat soak problem. I'm begining to wonder if those computer muffin fans in the inner fenders that Henry Constanzo (Georgia Z Club Pres.) put in his V8Z might be the ticket for lowering temps when the car is idling in traffic of even to have them run from a thermostat while the engine is off to cure heat soak. It seems some sort of active system is needed to evacuate the hot air from the engine bay after shutdown. Exchanging the hot air for cooler air would tend to cool the engine/starter/etc. Sorry for the rambling. [This message has been edited by pparaska (edited September 28, 2000).]

Ross, I'll have to investigate the rear rate a bit more. Alot of this was from listening to Jim Biondo and Les who used to be at Carrera Shocks. They both felt that going to less that 275 on an 8" spring was asking for trouble on the rear of a Z. I just occurred to me that I need to find out what the wheel rate to spring rate is for the car, then I can make some calculations as to what would be a minimum rate and stroke for a n 8 inch spring. Time to pull the Puhn, and Carroll Smith books out... But eyeballing it, it looks like the wheel rate would be about 8 or 9/10 of the spring rate. I'll measure it. (lift the wheel with a jack a certain amount at the center of the tread, and measure the movement in the spring). BTW, what is a good multiplier to use for a road race car and a road car, as far as the static weight at the corner, and what the max load would be if you hit a dip, etc?

...and if the opposite wheel is turning, but at a slower speed, all bets are off. The best thing to do on an open rear is hold the other side from turning and multiply the ratio of input-to-one-axle turns by 2.

Mike, I have Jim Biondo's old wheels, (WRD 3 piece): 17x9 on the rear and 17x8.5 up front. I also have the Arizona Z brakes on the car. The Wilwood hat used for the rear is 1/2" thick at the mounting flange, so take that into account for the backspacing numbers I'm giving next. Rear backspacing: 149 mm (5.87") Front backspacing (w/ 1/8" spacer): 142mm (5.59") I've sectioned 1.5" from the strut tubes, and used 240Z front cartridges in the rear, and Rabbit cartridges in the front. To get these wheels to (just barely!) fit I had to use a 8" spring so that the spring perch on the Carerra coilover was not touching the rim lip. Any lower (longer spring) and the spring would interfere with the tire and rim, any higher (shorter spring) and the rate goes through the roof, to keep from stacking the coils on bumps. As it was, I wouldn't try much less than a 260-275 lb/in spring, as any lower rate springs would probably coil stack on bumps. Please note that this was using the stock upper strut isolator and stock upper spring perch with muffler tubing welded to the center to center the spring. If you go to camber plates, things change. 7" springs? What rate were they talking about? I'd think that for the weight of the Z (600-ish pounds in the rear on each tire), you'd need a very stiff spring at 7" to keep from coil stacking. One thing you could do is use a longer spring and use camber plates, as this usually (depending on the camber plate and spring perch designs) lowers the car. There for, you could use the longer springs to raise it up, over the 8" springs and stock isolator/perch setup I used. I'm thinking about cutting down the stock isolator by 1/2" and using 9" springs. I haven't found a rate I like in the few 9" 2.5" springs I've found. ------------------ Pete Paraska - 73 540Z - Marathon Z Project - pparaska@home.com">pparaska@home.com -

Al, I'm confused by what MSA told you. Yes, if you use lowering springs, you get reduced bump travel and you tend to bottom out more. The higher rate offsets that somewhat, depending on the rate change. If they mean that the stock struts didn't have enough damping to keep up with the higher rate springs, I agree that is probably and issue. I used MSA springs and KYBs and it road rough, maybe that was why. Putting shorter strut cartridges in a stock length strut housing and spacing it up with a spacer underneath it does nothing as far as I can see, except maybe take away from bump travel in the strut. Lowering springs and a performance strut is a proven way to get a lowered car that handles a better on smooth roads (where bump travel is less important) because of the higher spring and strut rates, and the lowering of the Center of Gravity (CG). The preferred way to lower is to section the struts 1.5 to 2" and use shorter cartridges (the stock ones won't fit in the original locations). You can do this and use stock springs, stockish front cartridges in the rear and Rabbit or MR2 struts in the front. But the stock springs are pretty wimpy for performance driving and a lot of torque will bottom them out on take off (in the rear). Hope that helps. Let me know if I'm all wet on this. ------------------ Pete Paraska - 73 540Z - Marathon Z Project - pparaska@home.com">pparaska@home.com -

Nope, not yet. The original posts I made about my plans for how to do it and a link to pictures of the mirrors are on these forums at: http://24.4.88.29/ubb/Forum9/HTML/000018.html

Lone, I've heard the same thing about the Edelbrocks - they're Carter AFB copies with some changes. I've also heard that the Holley power valve blow out thing was fixed - Holley supposedly puts a check valve in the power valve signal passage so that it can only get sucked on and not blown . I put in the Spectre version into my old 3310.

Al, I can't remember the year, but it was a long run with the same struts. Pick anything in the 80s and you should be fine. But the only reason to put in shorter strut cartridges (240Z fronts in the rear, rabbit or MR2 fronts in the front) is because yu have shortened the strut tubes by 1.5-2". Then you'd need the shorter cartridges. Putting lowering springs on top of this combination will lower the car even further. Are you sure you want to go about it this way? The problem with the shorter springs is that they take away suspension bump travel, and you end up hitting the bump stops on large dips, etc.

These days, cross drilled rotors are usually used on race cars to lighten the discs - At least according to alot of reading I've done, and the Wilwood catalog and web site. Out gassing of pads is not usual with recent pad technology, once broken in. But lightening is not always good. Fade resistance is somewhat a function of rotor mass and venting. For a rear disc application, I'd think fade is less of an issue than the front.

Todd, have you considered a Grand National swap? It's been done, and kicks butt. High tech is nice, but a GN packs alot of punch for the weight/money. An LS1 V8 from a Camaro is also high tech to some. Push rods aren't that bad of a low tech thing considering the power density of this setup. The flat torque of that motor is pretty phenomonal. The heads are the benchmark of pushrod engines, according to many.

Andy, I think you are basing your theory on intake air temperature/density. Very true that colder intake temps mean a denser charge and more power available in the compressed mixture, plus better knock resistance.. But that is only one of the temperatures that matters to the efficiency of the engine cycle, the other being the temperature of the charge after compression when ignition occurs. If the intake temp is the same (not affected by coolant temp) then if you increase the combustion charge temperature (after compression) you get a more efficient combustion process, like you stated. The thing is that more efficiency is your friend for making more power with the same fuel! The two do not oppose each other. The main reason that the new muscle cars can beat up on the 60s ones in the quarter, etc. for less fuel burned is that they are more efficient - not a bad thing! The larger the difference between the intake temperature (for reasons beyond just density) and the combustion charge temperature, the more power and efficiency the same engine has. This is all based on an adiabatic (no heat loss) perfect model, but if the same heat loss exists for both cases, it's a fair comparison. Sure a hotter running engine will loose a little bit more heat than a cooler running one, but not enough to make a big difference. So yeah, a cooler, more dense intake charge is better. But so is a higher combustion chamber temperature, which you can effect with a higher temp thermostat- up to the point that you get that local boiling I was referring to. John brought up the issue of possible hotter oil (from running a higher coolant temp) splashing on the underside of the manifold and heating the intake charge. Good point as that causes difference between the intake temp (actually the temp of the mixture before compression, which is what matters) and combustion temp to get smaller than if the manifold were insulated from the engine. But the under manifold splash tray or an air gap type manifold should help this. As would having a heat barrier coating put on the underside of the manifold.

Scarp, I think the 180 or 195 thrmo is worth trying, especially on a wet intake system. It should raise the efficiency of the engine (more power from the same fuel) from a strictly thermodynamic engine cycle standpoint, but it might cause local boiling on the waterjacket surfaces adjacent to the combustion chamber. When you get local boiling there, the metal temps go up and you get hot spots that tend to cause pinging. I think it's worth messing with, especially if you have a Gtech or access to dyno time abd can do back to back comparisons. Not sure if a Gtech would be accurate enough though. Scarp, I hope that helps clarify my ideas?