Europeen style 3800 turbo swap - what do you think ? (Page 3/14) Englishrafe FEB 26, 06:14 PM At the end of the day I started on one of the heads. Not too much progress, just smoothed up one combustion chamber: Here's a close-up of the head - kind of before and after when you compare the two combustion chambers: I think it looks pretty no ? These heads are light-years ahead (in terms of design) of my oldsmobile heads in my Trans Am! It's going to be so easy to get them up to scratch. Only trouble is time - probably won't get to do any more before next week end now. (long sigh.......!) Jfrost FEB 26, 07:51 PM Nice progress so far. Keep up the good word! Darth Fiero FEB 26, 07:56 PM quote Originally posted by Joseph Upson: I put the intercooler in that position to test the validity of having an intercooler in that location, after driving nearly 500 miles with more than 90% of it on the hwy between FL and GA and seeing pretty much the same inlet temps (with my IAT sensor mounted just before the throttlebody) I saw no reason to have it on the car at all as it was a greater contribution to increased weight than intercooling. If at 70 mph there's not enough air moving underneath the car to make a significant difference, how much more moderate city driving. That 6" tall core is hanging more than 2" in the expected air stream, it's more like 4". the core is 3.5" thick and 18" long. First off, the way you explain you had it mounted tells me that there probably wasn't even airflow hitting a full 2" of your 6" tall IC core. So I'm not surprised at the results you got. You need to understand that there isn't much air flow right up against (or even within 1" of) the bottom of the Fiero's chassis. The bulk of the air flow is going to be more than 1" away from a given surface like this. quote The core facing the expected air stream is the most effective positioning and wouldn't require fans at all which would only be effective at speeds low enough to allow them to pull more air through the core than is already flowing, after that there is a risk that they may impede flow if a speed is reached where air is attempting to pass through the core faster than the fan can pull it. Not true, at least not in the environment we are talking about here. You are basing your assumption on the scenario of a core mounted on the front of a vehicle – in which case you WOULD BE CORRECT in your statement. But, airflow dynamics under a car are much different than what the very front of a car encounters (see my previous paragraph). Based on the fact that less air flows under the car than what the very front of the car encounters makes the presence of a fan that more critical when an IC is mounted in back. quote Your intercooler arrangement as well as one other I saw with the intercooler angled is what inspired me to test the arrangement. If hardly enough air is moving under the car to make an impact with the intercooler hanging directly in the theoretical air stream, I can't see where an air dam in the same location will make any difference attempting to direct already non existent air 90 degrees upward into an intercooler which is a less favorable position than what I setup temporarily and so far no one has come forward with any proof (data or experience) to the contrary. I guarantee you there is a lot of air moving under the car any time the car is in motion – at least on a Fiero that sits at or near stock ride height. Your post suggests there is very little air moving under the car and I have to say that statement is incorrect. Don’t believe me? Get some airflow sensors with remote displays and do some testing. I bet you are going to be surprised at the results. The way you had your intercooler mounted under the car in the picture shows me it would in fact NOT be very effective. I can see in your picture that there is just too much space between the sides and bottom of the IC for air to move around it instead of thru it. The fact that you also did not have any fans at all mounted to that IC further explains why that IC didn't do a thing for you. I'm not surprised you got the results you did. I could have told you before you even put it on your car the way you did (in the picture) you would have gotten very poor results; so I could have saved you the trouble. I think some of you people fail to understand airflow dynamics as well as what the importance of having an airdam is. If you don't understand what I am trying to explain here, then there is a simple test you can do on your own Fiero that will demonstrate what I am talking about. Go out and unplug your radiator fan and also remove the factory airdam from under the core support. Now drive the car on a 70 deg or warmer day and tell me what happens to your engine's coolant temps after some driving. I bet you are going to find your engine runs hot and probably wants to overheat regardless if you are moving down the freeway at a good clip or if you are sitting still. The function of the airdam is 2-fold. 1) It directs some air to flow up into the area just above and ahead of it, and 2) it creates a lower pressure zone behind it that helps draw air down from the comparment above and behind it. If you go look at just about any GM car that has a small grill area, I bet you are going to see an airdam of some kind hanging under the core support. There is a reason why GM put these on their cars and I can tell you from personal experience the cooling systems in these cars do NOT work well without them. quote It appears I'm the only person with an IAT sensor placed just before the throttlebody and after the intercooler in order to know for sure if such an arrangement is productive. When I mounted the intercooler up front my inlet temps dropped by at least 100 deg, I posted before and after logs of those results in my 3900 build thread. I didn't post any logs on the above arrangement because I have no reason to lie about it and the fact I removed it from the car altogether should be proof enough it was worthless in that location. Take the airdam off your Fiero and disable the electric fan. Then re-run your tests with your water-to-air IC and let me know what happens. I bet you are going to be surprised. quote Originally posted by Justinbart: I have the IAT sensor half way between the intercooler and the TB. After several miles of driving it will read 10-12* over ambient then an additional 16* during a long run under high boost. So if its 70* outside it will say 70* and eventually clime to 82* while cruising and 98* under boost. Then it falls back to 82* after 20-30 seconds. I'm not sure if scott has any scans of the IAT. I just watch it on the Scanmaster. I don't have an IAT sensor before the intercooler but FWIW I can tell you that the hot side is too hot to touch and post intercooler is cool to the touch. In order to run an accurate temperature drop test you would need at least two properly calibrated IAT sensors; one installed between the turbo and IC and one between the IC and TB (it would also be best to have a 3rd mounted near your air filter between it and the turbo's inlet so incoming air temp could be measured). Just having one installed and giving you readings from one point doesn't tell us much. I've seen factory IAT sensors provide wildly inaccurate air temp readings vs. actual outside temps. I'm not saying this happened to you during your test, but it is a possibility. Also, if you want to know the efficiency rating of your IC, you would also want inlet and outlet pressure readings in addition to the charge air temp readings. quote Originally posted by Racing_Master: the way air flows through the engine compartment. it goes from bottom up, taking out the heat via the decklid vents. This is the natural tendency of airflow thru the engine compartment of a Fiero. My IC placement puts the IC right where air naturally wants to enter the engine compartment on a Fiero. Adding the airdam forces more air from under the car up into the engine compartment (and thru the IC core). Darth Fiero FEB 26, 07:58 PM quote Originally posted by 1fatcat: Actually, it was the lower intake manifold that was redesigned. It had a smaller diameter stove pipe for the egr. The smaller pipe allowed for a larger air gap between the pipe and it's recieving bore hole in the plastic upper manifold. This hole is where the manifold would get brittle, break open to a water passage behind the throttle body and induce coolant into the intake. In some cases, this would hydro-lock the engine on start-up and bend connecting rods. The larger air gap kept the hot egr stove pipe from deteriorating the plastic upper manifold. Then why were there updated upper plastic plenums sold for L36 engines? I bought such a plenum from Napa years ago and it came with a paper explaining the design change (IE: coolant ports moved closer to EGR pipe hole and an enlarged EGR pipe hole so the actual EGR pipe was further away from the plastic - in that particular design anyway). Joseph Upson FEB 26, 08:53 PM quote Originally posted by Darth Fiero: I think some of you people fail to understand airflow dynamics as well as what the importance of having an airdam is. Not to provoke argument but, I trust my experience over your speculation here. I honestly believe this is more of a not wanting to be wrong about anything issue for you than actual fact. You have a rebuttle for everyone's concern in support of your own theory/assumption or belief here Darth. Just post some data to back it up, that'll help us all. That's the only way you'll get me to believe the intercooler and airdam arrangement you posted is actually more effective than letting the intercooler hang in the supposed air stream that your airdam is supposed to direct 90 deg upward through that intercooler. It looks great as far as the install, but I highly doubt it performs anywhere near as good as it looks. Am I to assume the factory airdam at the front of the car conditions the air in a manner to further enhance the second one you added down stream from it? Another plus for the air to water intercooler is the fact that it was installed from the factory on the Syclone and Typhoon and the radiator for that system appears to be small enough to fit up front in the air stream in the same location I installed my intercooler out front. If I recall correctly it's also in use on at least one or more current GM muscle cars. Englishrafe FEB 27, 02:55 AM Thanks to Jfrost for the words of encouragement. For the others who are "hijacking" this thread for the airflow discussion - please keep it "on topic" ! I would still like feedback on the compression ratio question - polishing the combustion chambers will take off a small amount of materiel (ie lower the comp ratio) but the smoothness (along with less carbon deposits) should help the burn caracteristics. I will measure the cc of a polished comb chamber compared to the stock one. Then I'll dig out my comp ratio formula and do the maths. The question remains, should I buy the 9.5:1 pistons ? Thanks, Rafe Joseph Upson FEB 27, 05:21 AM quote Originally posted by Englishrafe: For the others who are "hijacking" this thread for the airflow discussion - please keep it "on topic" ! Rafe Sorry about that but understand, you cause confusion when you start a thread with a question; "Europeen style 3800 turbo swap - what do you think ?" "Intercooler - thinking of a water/air unit with a secondary radiator up in the front." I don't think it's a hijack at all given the above, certainly not intended. The discussion is directly related and relevant given the above two quotes. If I'm wrong in my stance on the subject in question, you should probably consider the arrangment Darth posted instead of the water air unit if you're still thinking about it. Englishrafe FEB 27, 05:27 AM OK, sorry, didn't mean to offend. I am keeping in mind all the info on inter-coolers - just haven't got that far yet. Rafe Joseph Upson FEB 27, 05:42 AM quote Originally posted by Englishrafe: OK, sorry, didn't mean to offend. I am keeping in mind all the info on inter-coolers - just haven't got that far yet. Rafe No offense taken, Darth probably does more tuning than anyone on the forum and should have data from some of the intercooled arrangements he has come in contact with to confirm what he's stating but as of yet has not posted any. We've had this discussion before and I'm still waiting to see supporting evidence because without an intercooler my inlet temps run as high as 180 deg at 7psi and that's a power loss you can feel among other side effects so the info is important. If he's correct I'll follow his lead but I doubt it in this scenario. I believe the Supercharged Caddi and Corvette run liquid to air intercoolers in addition to the Syclone/Typhoon pioneer vehicles. 1fatcat FEB 27, 03:42 PM quote Originally posted by Darth Fiero: Then why were there updated upper plastic plenums sold for L36 engines? I bought such a plenum from Napa years ago... I have no idea what the aftermarket did, probably nothing, or not enough. I'm refering to GM's fix for the problem. Read this>>> http://www.justanswer.com/u...3.8_upper_intake.pdf