CHOSENMAN007 81 Report post Posted May 22, 2015 A random one. Out of curiosity why is a avo turbo mounted low in the engine? Most turbo kits are mounted top end. What are the advantages and disadvantages in where you mount a turbo. I understand most kits mount above the oil sump for cooling, if I understand correctly. As you can tell I'm clueless on turbos. James. Share this post Link to post Share on other sites
Minion 132 Report post Posted May 22, 2015 I don't have one.........Yet but I am fairly sure that one of the reasons is to keep the weight as low down as possible which is the whole idea of the Boxer engine and a big reason on why the car handles so well . I am not 100% on this answer so if someone could confirm that would be great. Share this post Link to post Share on other sites
Tareim 343 Report post Posted May 22, 2015 the exhaust manifold is on the bottom of the engine so to save from routing hot exhaust pipes up the car the turbo would be mounted lower, also helps on the centre of gravity to have things as low as possible Share this post Link to post Share on other sites
Lauren 2259 Report post Posted May 22, 2015 In a nutshell the closer the turbo is to the exhaust ports, the less lag there will be. Though admittedly it's a little more complicated than that. Share this post Link to post Share on other sites
Kodename47 446 Report post Posted May 22, 2015 Some will argue that having something that generates heat near the oil pan is a bad idea vs those that worry about engine bay temps and the issues that causes. The routing is a little less important as I bet most of the up and down turbo manifolds mount the turbo barely any further away from the exhaust ports. Share this post Link to post Share on other sites
CHOSENMAN007 81 Report post Posted May 22, 2015 So there is no best set up really I guess? Share this post Link to post Share on other sites
hashiriya 52 Report post Posted May 22, 2015 From my experience top mount turbos are generally used for a number of reasons. The first is that the manifolds tend to be under less stress. Tubular manifolds under high temperatures can be quite stressed and crack from the weight of the turbo plus the vibrations and forces of the engine moving etc. It's generally easier and stronger to have a manifold which can use the tubes themselves under compression to help support the weight of the turbo. The second is a more efficient routing of the intake piping system and also space to mount the turbo itself. Aftermarket turbos can be quite large and you tend to find that they can sometimes struggle to fit between the engine and the chassis around it. The third is ease of maintenance if you can reach it easier. Regarding the oil sump, most turbos have a pressurised feed to get oil in but rely on gravity to get the oil out. This would mean that you need to have the turbo positioned higher than the oil sump (Although I would struggle to see how any any car you would get the turbo so low) but from a practical point of view, I would guess that anyone choosing to place their turbo close to the oil sump is doing it to minimise the length of the oil return line. There are many considerations when it comes to turbo kit design but most of it is dictated by the space you have available to work with and the ideal routing for your intake and boost piping. 4 Ztox, CHOSENMAN007, adamj29 and 1 other reacted to this Share this post Link to post Share on other sites
CHOSENMAN007 81 Report post Posted May 22, 2015 That certainly educated me on turbo placement mas. Cheers Share this post Link to post Share on other sites
Guest Report post Posted May 22, 2015 I have a Stage 4 AVO and a JDL system with GTX 3071. One obvious reason AVO have kept it low is the standard parts of the car are retained. With the JDL kit the turbo requires the fans be changed as the plastic fan housing of the stock car gets in the way. The cooling and lubrication lines are quite "in your face" under the bonnet. Theres also the issue of oil drain back, which has already been mentioned. the AVO system uses a scavenge pump which removes the need for any sump mods and keeps the plumbing very tidy. Which one will I use??? well we'll just have to wait and see... Share this post Link to post Share on other sites
Ztox 230 Report post Posted May 22, 2015 I must admit I thought it was mainly a heat thing on these cars, there are examples of both top and bottom mounted turbo kits for the 86 though that I've seen Share this post Link to post Share on other sites
CHOSENMAN007 81 Report post Posted May 23, 2015 I must admit I thought it was mainly a heat thing on these cars, there are examples of both top and bottom mounted turbo kits for the 86 though that I've seen I thought so too. But I wondered why the real big power turbo kits the likes of Crawford and full blown mounted high up. Their base kits punch well above a avo kit even the stage 4. I feel mas gave a pukka explanation in this subject. 1 Ztox reacted to this Share this post Link to post Share on other sites
rob275 1817 Report post Posted May 23, 2015 I thought so too. But I wondered why the real big power turbo kits the likes of Crawford and full blown mounted high up. Their base kits punch well above a avo kit even the stage 4. I feel mas gave a pukka explanation in this subject. There's no room underneath Share this post Link to post Share on other sites
Special K 442 Report post Posted May 24, 2015 Good explanation, Mas. The AVO kit is supported by a bracket which fixes vertically to the engine block immediately above the turbo body. As well as taking the 'hung' weight off the exhaust manifold pipes it synchronises the engine/exhaust manifold vibrations with the bulk/weight of the turbo. As I have mentioned elsewhere turbo heat buildup in the engine bay is an issue but is only significant when we are talking competition and can relatively easily be addressed by venting the engine undertray. A further simple diy 'tweak' would be to replace the GT86 side fenders with the BRZ version, remove the solid plastic inserts and replace these with proper grills. Nige will have a larger heat issue to consider if he uses his high-mounted 'big' blower in battle, I would suggest.. Spec K Share this post Link to post Share on other sites
Kodename47 446 Report post Posted May 24, 2015 A further simple diy 'tweak' would be to replace the GT86 side fenders with the BRZ version, remove the solid plastic inserts and replace these with proper grills. I doubt many would think that cutting a hole in the metal bodywork of an engine bay as simple DIY The trims have no direct path into the engine bay: 1 Keethos reacted to this Share this post Link to post Share on other sites
Guest Report post Posted May 24, 2015 A further simple diy 'tweak' would be to replace the GT86 side fenders with the BRZ version, remove the solid plastic inserts and replace these with proper grills. Nige will have a larger heat issue to consider if he uses his high-mounted 'big' blower in battle, I would suggest.. Spec K Thats exactly what i plan to do to my side fenders Keith, but as knightryder mentioned, it'll entail cutting sheet metal.. not too sure I want to start cutting my car about though i will have heat issues as well, but a vented bonnet will help no doubt. Share this post Link to post Share on other sites
Special K 442 Report post Posted May 25, 2015 I don't do cutting. Well, not metal.. Hence my suggestion - the 'vent' that is shown in the photo above, is repeated both sides. Added together that's nearly the size of a letterbox. And, if you think about it, there is zero ventilation in this area - airflow around the wings/either side of the bonnet will suck the hottest, stillest air out of the engine compartment. (Added to which it looks good.. not that I do 'bling, of course...) Spec K Share this post Link to post Share on other sites
