Gazzar Posted March 11, 2020 Author Share Posted March 11, 2020 I understand, having fuel atomising in the vicinity must mess with the air density, if nothing else. I could pipe from that aperture to a point within the manifold that might suit. A pilot tube. Quote Link to comment Share on other sites More sharing options...
Bigj66 Posted March 11, 2020 Share Posted March 11, 2020 I thought you only needed a MAP sensor if you wanted to go down the turbo route? I fitted one to my Cosworth Capri with the Emerald K6 ECU but only to future proof it in case I wanted to turbo it. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted March 11, 2020 Share Posted March 11, 2020 1 hour ago, Gazzar said: The issue that FF raised? Good to know. Yup. The 3.9/3.5 Rover V8 plenum is known for this, and is why most people block off the little vacuum advance nipple, and use one of the take offs on the side of the plenum. I suspect you will probably be OK with that position, but may be worth asking the question of VW speedshop. Otherwise drilling and tapping the inlet manifold to put a barbed fitting in is hardly a big job Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted March 11, 2020 Share Posted March 11, 2020 12 minutes ago, Bigj66 said: I thought you only needed a MAP sensor if you wanted to go down the turbo route? I fitted one to my Cosworth Capri with the Emerald K6 ECU but only to future proof it in case I wanted to turbo it. If you are referring to having a TPS, this is useful for tuning acceleration enrichment ( as well as other things) , something that is vital if you want the engine to pick up properly from idle. Also used to know when the engine should be idling. Quote Link to comment Share on other sites More sharing options...
Bigj66 Posted March 11, 2020 Share Posted March 11, 2020 1 minute ago, Bowie69 said: If you are referring to having a TPS, this is useful for tuning acceleration enrichment ( as well as other things) , something that is vital if you want the engine to pick up properly from idle. Also used to know when the engine should be idling. No I was referring to the MAP (Manifold Absolute Pressure) sensor connected to the inlet manifold. I thought they were only required for turbo applications 🤔 The TPS is definitely needed. Quote Link to comment Share on other sites More sharing options...
Gazzar Posted March 11, 2020 Author Share Posted March 11, 2020 For me, part of the fun is learning about the various sensors, and fitting them, too. So, even if it's not absolutely necessary, I'll fit it. For instance, I'm fitting a flex fuel sensor, as I expect that high concentration ethenol will be a feature of fuel in the future. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted March 11, 2020 Share Posted March 11, 2020 Having a map and inlet air temp sensor allows you to tune the engine correctly for changes in density and temperature. Without this you can run a car with just TPS, but it has no capability to adjust for these variables. More suited for track cars and the like really. Quote Link to comment Share on other sites More sharing options...
Gazzar Posted March 11, 2020 Author Share Posted March 11, 2020 Where is the air temp sensor usually plumbed? Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted March 11, 2020 Share Posted March 11, 2020 There's some misunderstanding here - Megasquirt doesn't have an airflow meter, it uses MAP and RPM (plus air temperature) to calculate mass airflow. It's quite nice for our purposes as there's nothing in the intake tract to get dirty. TPS is only used for acceleration, and it's only the rate-of-change (how fast you moved the pedal) it cares about. Quote Link to comment Share on other sites More sharing options...
Gazzar Posted March 11, 2020 Author Share Posted March 11, 2020 TPS determines the required engine speed, doesn't it? Quote Link to comment Share on other sites More sharing options...
Bigj66 Posted March 11, 2020 Share Posted March 11, 2020 2 minutes ago, FridgeFreezer said: There's some misunderstanding here - Megasquirt doesn't have an airflow meter, it uses MAP and RPM (plus air temperature) to calculate mass airflow. It's quite nice for our purposes as there's nothing in the intake tract to get dirty. TPS is only used for acceleration, and it's only the rate-of-change (how fast you moved the pedal) it cares about. That explains it 👍 Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted March 11, 2020 Share Posted March 11, 2020 2 minutes ago, Gazzar said: TPS determines the required engine speed, doesn't it? No, your foot does! TPS is only used like an accelerator pump on a carb - the harder you mash the pedal (how fast it moved) the bigger dollop of fuel MS will pump in: You can see top-right, the TPS rate-of-change (volts/second) and the amount of accel-pump the ECU will do, in extra milliseconds of injector opening. You can also switch to MAP-based (MAPdot) which uses the rate-of-change-of-MAP instead. This is useful in a bouncy series where bouncing over bumps can cause your foot to jiggle the pedal and keep triggering the Accel enrichment, although you can tweak the rates (v/s) to tune this out. 15 minutes ago, Gazzar said: Where is the air temp sensor usually plumbed? Somewhere it can sense outside/intake air temp, it's really not critical - mine's in the air filter housing. AT1010 as supplied by Nige is an M14 thread I think and has the right response for MS's default setting. While we're here: You *can* use an airflow meter with MS, just like you can use no MAP sensor at all and just guess based on RPM (alpha-n I think it's called) if you've got a drag-racing engine with an insanely lumpy cam. You can also add nitrous, launch control, fan control, shift lights... Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted March 11, 2020 Share Posted March 11, 2020 As above, precisely. Alpha-N is not that great for road cars, speed density is where it is at for older engines, conversions and harsh environments. a bit of reading: https://www.carthrottle.com/post/whats-the-difference-between-maf-and-speed-density-setups/ Air temp in the inlet tract, often found in air boxes, but not critical, put it where you find it simple/convenient for the wiring. Quote Link to comment Share on other sites More sharing options...
Gazzar Posted March 11, 2020 Author Share Posted March 11, 2020 It might get oily in the air filter, so I might add it to the swan neck. So, is the engine speed set by a throttle plate in the throttle body? Like a carb? Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted March 11, 2020 Share Posted March 11, 2020 25 minutes ago, Bowie69 said: Alpha-N is not that great for road cars, speed density is where it is at for older engines, conversions and harsh environments. TBH 90% of the features and stuff tuners write about is completely irrelevant for our purposes round here - there's no money in basic boring stuff! MS has run everything from lawnmowers to land-speed-record cars, if anything it causes problems because it can do so much people get lost in picking the basic ~10% they actually need to care about. 1 minute ago, Gazzar said: It might get oily in the air filter, so I might add it to the swan neck. So, is the engine speed set by a throttle plate in the throttle body? Like a carb? Air temp sensor won't care about a bit of oil, it's only really hotwire type airflow meters that get upset. And yes, all you're doing is replacing a leaky bucket with a computer-controlled squirty thing, the throttle plate etc. is the same. The MS code is written a lot like a "carb simulator" compared to other EFI systems. Some people retain the old carbs as throttle bodies with an injector or injectors mounted downstream. Quote Link to comment Share on other sites More sharing options...
Gazzar Posted March 14, 2020 Author Share Posted March 14, 2020 Conrod bolts! Reading the manual I see I've to replace the bolts. Minefield! Turner list the wrong part number. The correct number is ETC7357, they suggest ERC8751 (2286 version). Prices are all over the place. Are Bearmach engine parts okay? Quote Link to comment Share on other sites More sharing options...
Gazzar Posted March 15, 2020 Author Share Posted March 15, 2020 Main bearing cap bolts are expensive. Nearly £90 for a set. Do I HAVE to replace them? They aren't stretch bolts. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted March 15, 2020 Share Posted March 15, 2020 No, unless the manual says otherwise they should be reused. I've never replaced main bearing cap bolts in my life.... Quote Link to comment Share on other sites More sharing options...
deep Posted March 15, 2020 Share Posted March 15, 2020 47 minutes ago, Bowie69 said: No, unless the manual says otherwise they should be reused. I've never replaced main bearing cap bolts in my life.... Likewise. However, I would make sure the threads are in excellent order (and that there is no damage, obviously). Two reasons. One is ability to handle the load and the other is that a mildly damaged thread could play havoc with your torque settings. But you knew that... Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted March 15, 2020 Share Posted March 15, 2020 If they're silly money take a look at ARP stud kits, if they do one that'd suit it's both a nicer thing and sometimes a cheaper option - IIRC for the V8 it's cheaper to fit ARP bits than all new genuine bolts, no brainer really! Quote Link to comment Share on other sites More sharing options...
Gazzar Posted March 16, 2020 Author Share Posted March 16, 2020 They are expensive, not quite silly. The manual says use new, but I was surprised by this. I've bought new head bolts, as I know the head had been off before, so that makes sense, but the main cap bolts are fine, I see no good reason to replace. If I was supercharging the engine I'd reconsider that decision, but I'm not. Thanks, original it is. Quote Link to comment Share on other sites More sharing options...
Gazzar Posted March 16, 2020 Author Share Posted March 16, 2020 Main bearing cap distortion testing showed all is good. No way in hell is the feeler gauge going in there. 1 Quote Link to comment Share on other sites More sharing options...
Gazzar Posted March 16, 2020 Author Share Posted March 16, 2020 And a gratuitous photo or two of how the manifolds interact, including the scientific dents: Quote Link to comment Share on other sites More sharing options...
Gazzar Posted March 16, 2020 Author Share Posted March 16, 2020 The current plan to fit the throttle body is to get a lump of alloy and bolt it through the holes previously used for the exhaust manifold. I'll drill and tap this block to take studs to hold the throttle body, with a lump of plastic between. All achievable with hand tools and baby pillar drills. Will normal gasket paper do in this scenario? Or is there some whizzy petrol manifold gasket paper I need to think about? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted March 16, 2020 Share Posted March 16, 2020 Normal paper would be fine, it is what carb gaskets are made of.... Has the throttle body arrived yet? Quote Link to comment Share on other sites More sharing options...
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