Hi, A month ago, I had my 308, 76, carb. exhaust insulation wrap from ThermoTech. to the exhaust from headers to tail pipe. The wrap should help retaining heat inside the exhaust so hot air will travel faster out off tail pipe therefore cold air will enter carburators faster = more horsepower. which after putting them on my car went faster. But I got backfire and big popping sound when turn off ignition. After advice from the Forum members, I had the carb. reset , backfire gone and the car perform better but still popping sound when turn off engine. Don't know how to get rid of this pop, big pop. Anyone have an experience with these wrap. Please advise. Pat Image Unavailable, Please Login
If you want even more hp wrap the intake system in heat reflective tape or paint. Dont know if your 77 has the same air box as my 84 but if it does I would send it out to be painted then (if it is on your 77) wrap the tube that takkes the air to the plenum. Since your car is carbed it may have a different system but there should be a way tp wrap the intake up which is even more important to hp than the exhaust Now to your question about the POP. I think whats happening is your wrapped exhaust is trapping the heat inside which is good except that it may wear out your exhaust prematurely & the pop is porbably a fireball. I dont think the fireball will harm the car but if you want your exhaust wrapped you'll probably have to learn to live with it
Never done it myself however it is done by the P car folks result is that the metal of the headers is destroyed by the heat since it can sink into the metal but can not be dissipated reports are that if you unwrap the headers after some time the simply crumble away not sure about that but ... However wrapping headers is the second best approach the right thing to do is to ceramic coat the inside / outside - that keep the heat away from the metal (and also looks nice) I use the following guys http://www.performancecoatings.com/
i used thermo wrap FOR YEARS on my muscle cars. i would NOT use it on a Ferrari. JET -HOT or similar ceramic coatings are superior. the wrap caused cracks, welds to fail, it holds moisture for LONG periods of time and the pipes will rust very quickly due to the heat cycling. my 308 had a pop / backfire at shutoff also. new intake and carb gaskets, carbs synced and the timing set. no backfire and the car runs better than i could have imagined!
Thank you William, I will try the air in take wrapping. You have pictures of yours wrapping. The pop wasn't there before the wrapping. I thought the wrap should help reduce the heat inside the engine compartment and increase air flow. But if it was going to rust. Then, it seem to have bad effect more than good. Pat
How is the wrap working with your muscle cars? Now I have second thoughts about having the wrap removed. Thank you.
i used it over a long period, many of the cars were sold after a short time. however, i live in a small community and i actually bought a few of the cars back. the headers had the above mentioned problems. the wrap holds moisture in the small spaces and accelerates rust. a set of headers for a GM muscle cars is not that expensive, and its easy to change them out on those cars. my experience with the wrap on the cars i kept for many years is also the same. i would most definately NOT use it on a Ferrari, given the cost of the parts and the difficulty in getting the manifolds out of the aluminum heads without something going wrong. my opinion is based on the fact that in less than a year, a quality set of both Pontiac and Chevy headers failed due to cracking with evidence of severe corrosion. while other similar cars ( mine and belonging to others) , the headers last for several years before warping / cracking. MR. Pong , you have some very nice cars, and i wish you the best , whatever you decide. perhaps one of the " regular' Ferrari mechanics can shed some light on this for you before you make your final desesion. i would go for ceramic coating!!!
Dear Pat, sorry for the delay but I was out with the car for the weekend. Here I give you the informations about idle at my GTB : normal idle speed R.P.M 1.000 (+ / - 50) with full operated A/C R.P.M. 900 (+/- 50) R.P.M only noticed on instrument, not digital tester. Best regards, AFire
The header on my QV are double wrapped and have been for 3 years and the headers on my bike were wrapped for 10 years. If the car gets wet, which doesn't happen very often, the headers steam for about 10 minutes, so it does hold water. The metal of the header has got to be hotter with the wrap on, so they will will corrode faster, although I did hose the wrap down with high temp paint which has got to slow down the oxygen getting to the metal...I guess that is the advantage of the ceramic coating, there is a good barrier to air (and the oxygen) and the metal will stay a bit cooler since there is an internal coating. Ferrari header are stainless steel, so they will corrode much slower than most aftermarket muscle car headers, but sooner or later they will go bad.
I glad this one came up as I was going to ask the question. It occured to me that a wrap might have been a good idea, I was stuck in traffic in Lemans and I could see the heat haze coming thru the grills (aptly named) at the back and thought that wrapping the pipes would get the heat out quicker. Cancel that idea !!
Pat, I've never heard of someone with a Ferrari having their headers go bad because of the wrap. Many guys here in Toronto have theirs wraped with no problems, I wouldn't worry too much about it...after all, how often does the wrap get soaked? I would have the valve adjustment done and rebuild the carbs, remember your car is 30 years old now, time to rebuild carbs, change rubber hoses and do the valve adjust.
Pat, I don't have any poping or backfire, but my car is far from stock. It's supercharged with EFI and making about 520 hp. I added the wrap to keep the extreme heat from the exhaust out of the engine bay and it seems to work well. The engine bay seems to be cooler than it was with the stock engine, but I never measured, so it's just my perception. Mark
WOW 520hp. That's a race car already. Can we see the pictures of it? I agree that the wrap help reduce heat in the engine bay a whole lot. Before wrapping, right after a fast drive I open the rear bonnet the heat would rush out and hit me in the face big time. Now it just not so bad. I can even clean up wipe off dust on the engine right after. Pat
Sure. There is a nice shot of the engine on the profile. This thread has the dyno results and links to all the pictures I posted while building it. http://ferrarichat.com/forum/showthread.php?t=24743
Why would you use header tape/wrap when ceramic coating works better, looks better and is not that expensive. I had the entire exhaust system , headers, pipes and mufflers on my BB512i ceramic coated inside and out for $450.00. If that's too expensive for you then maybe you should reconsider Ferrari ownership?
It's the work better part I've never found to be true if keeping heat out of the engine bay is what your after. With my wrapped headers, I can take the car for a 30 minute drive then put my hand on them (very briefly) without burning any flesh. I've never found that to be even close to true with coated.
I had my car back and everything is running great. I kept the wrap on. And car running smooth. Idle is stable at 900 to 1000 RPM. AND NO POPPING. This mechanic is good. Eventhough he is a Lotus mechanic. He set the carb. ignition time. What happen with the popping was that the ignition time was off. It was firing when the ignition was off. That's cause the pop. Now I need valve adjustment and set carb again and my car will run like new.
mk e, keeping the heat out of the engine bay is only an ancillary benefit to ceramic coating or thermal wrapping your exhaust. The designed and most beneficial benefit is to keep more heat in the exhaust flow which speeds it up and improves scavenging and thus power. Since most Ferraris, at least modern ones, have their air intake plumbed from outside the engine compartment, heat in the engine compartment doesn't affect the intake charge cooling much if at all. Ferraris all have more than adequete cooling systems too so engine compartment heat doesn't contribute to overheating either. Just why would one be overly concerned by how much heat was in the engine compartment anyway? So, since cermanic coating does what it is designed to do better than thermal wrap, looks better, is not that expensive and prevents rust and/or corosion, why would one not use it over thermal wrap?
I think see what you're saying, but I don't think it's quite right. I know the numbers for my engine, so I'll use that as the example. With the car sitting still on the dyno, the cooling system with just the electric fan will maybe keep the temperature stable at full power up to about 3000 rpm. The fan is rated at 2400 cfm, the cooling system runs at 180F, say an 80 degree day, also say the radiator is perfect so the air going through the radiator comes in at 80 and goes out at 180, a 100F rise. So its dumping about 57000 BTU out the radiator. Then engine is using about 262 cmf and discharging it at 1200F, so 70000 BTU. So only 45% of the waste heat is going out the radiator if it was perfect, in truth 70% is probably about right, so only 31% of the waste heat goes out of the radiator with the rest going out with the exhaust. The cooling loop runs at 180, so if the engine bay temp is above that, then heat from the exhaust will begin to transfer back into the engine and increase the load on the cooling system. I dont know about other models, but a 308 has a very very marginal cooling system. It works well when new, but not so much as it ages so anything to help it has got to be a good thing. The other thing is that engine bay temp does make a big different to the life of any non-metal parts. In industry, artificial aging is done by increasing the temperature the item is used or stored at. As a general rule, the rate of decay doubles every time the temperature is increase 10C,(20C=4X, 30C=8x, 40C=16x, ect) so dropping the engine bay temperature will greatly extend the life of belts, hoses, seals, wire insulation, ect. Heat is just plain bad and before wrapping the headers opening the hood was like opening an oven door, it had to be 300+F in there. Now its not, maybe 200F. I have to believe thats a good thing. And my engine makes a lot more heat than ferrari planned for, so that was my concern, any hp gain would be nice, but not very important to me.
