thehelix112

Touche`

Look at the left most curve. From a easy rolling start I go to around 65% throttle when RPM (red curve) is around 3000rpm and boost (black line) gets close to full boost (before redline @ 6500) just over 1 second later. Thats in 1st, with a GT35R (granted still a T3 essentially), and a SOFT WASTEGATE spring! I wish I hadn't blown my headgasket because it comes on atleast 0.5 sec faster with a proper spring in the wastegate. Go put a spring on the damn wastegate and see what happens! If its the stock turbo god knows what the spring pressure is at. Here is a nice little tutorial: http://www.ozdat.com/ozdatonline/techstuff/boost.htm Dave Dave

Lack of throttle response and turbo lag are the same thing. Its quite easy to eliminate. Use an antilag system and replace your exhaust valves, exhaust manifold, turbocharger regularly. Or, use a VNT turbocharger and replace that regularly as the temperature at which petrol burns reduces the vains to nothing in short order. Aside from that, as Tony mentioned, having the throttle bodies as close to the head has always improved throttle response. Dave

Tony, I'm curious about this. How do you keep the turbo spooled via a separate wastegate? How would it be driven when you back off? Having throttle bodies in the runners is for improved throttle response (aka, less lag). Great if you go from puttering to racing often. Dave

Point of interest on todd's rims, does anyone know the offsets by any chance? Specifically the rears? I'm about to try to get 9" rims under the std rears. Dave

So you're telling us it takes 2 full seconds to get from 2000 to 2500? :S Oh and its still perfectly possible for the wastegate to be creeping. By creeping I mean being forced open by the pressure in the exhaust manifold, not being actuated by the intake pressure via the wastegate diaphram. Dave

I didn't know Nissan/Fuji made Viscous LSDs in the long nose casing. Are you sure? Dave

Dude, FFS http://forums.hybridz.org/showthread.php?t=105049&highlight=N36 http://forums.hybridz.org/showthread.php?t=75969&highlight=n36 Took me all of 30 seconds to find those. Dave

Short story IMHO. Lots of effort for not much gain. Dave

Where to find the search button. *points upwards* Dave

I think you'd be better off just running a basic duct to the front of the car and then onto the air filter if there is room. At the very least add to the shield so it covers the 800 deg C exhaust manifold as well. Dave

Tony D, I was just about to edit my post and say just that re threshold vs lag. I'm well aware of the difference but still made the slip up. Sorry all. I would also like to echo your comment about incorrect driving technique. If you're complaining about it with regards to track work then you're in the wrong gear. But its always interesting to think about these things. Dave

turbobluestreak, I just had the tailshaft shortened by 50mm (2"). The tranny mount I'll take a picture of next time I'm at the car. Its basically two bits of flat, one which goes to the transmission, the other to the x-member, then join them with two small bits of metal. No rubber mounting but there is rubber in the x-member to chassis connection and it appears to be just fine. Tony D, Yes the shifter is in the same spot. No changes there. You may THINK you have to beat the flare at the bottom of the stick to clear the hole, but thats only because your engine is leaning backwards because you forgot to chock it up after you got the gearbox out Dave

Jeremy, We are saying the same thing about timing equating to boost. I think it will be a matter of walking the fine line between using the combustion for power (more advanced) or for boost production (less advanced). If we get boost production then we have more combustion to split between maintaining boost and making power. Will do some testing Autronic has nice datalogging so will be able to get some decent data for us to examine. I will also eventually have a crack at the Autronic anti-lag system and get some datalogs of that in operation so we can see exactly what its doing in terms of advance as rpm/boost change. Dave

Can we get back to the topic at hand perhaps? The question I think was whether we want to advance our off-boost timing or retard it to get earlier spool up? I think the answer to this question is retard, ala anti-lag systems. The reason why these work is the massive pressure increase which occurs during combustion is not being used to drive the piston downwards but is instead directly exiting the head and increasing the pressure in the manifold and driving the turbocharger. What does this mean for you and me. If you retard your timing a lot in your pre-boost maps you turbo will spool a lot and your engine will run like a piece of crap off boost. I will have a play with this when I get the boost control sorted. It would seem that massive retard in pre-boost maps will cause the turbocharger to spool and can then go back into proper advance so the engine can make some power. The question I have is whether it will oscillate backwards and forwards? Ie, if i retard my timing so much that it'll make 10psi @ 2000rpm on moderate throttle, and it does, this then pushes the map into proper advance @ 2000 which then means the turbo is spinning down as it doesn't have the gas to drive it, as soon as it gets below boost it'll go into retard and spin up again. Maybe thats why WRC cars only have anti-lag for throttle-off applications. Maybe a compromise and having moderate retard down low, but not so much that the car runs like a slug will spin up the turbo a little faster and have it blend into proper power advance when on boost? Dave zguy36, forums are often a place for **** talking, but there are always a few people interested in learning. Please stick around, you obviously know what you're on about.

bastaard, As previously mentioned a turbo works on pressure differentials, specifically, higher on the manifold side than on the exhaust side so here are some things that will either decrease the manifold side, or increase the exhaust side: 1. Wastegate creep! - just experienced the difference this will make. Used to get 4psi by 3250 but have to wait til 4500 for 11psi. Now I get 11psi around 3750. Hell of a difference. Fries the tyres in 4th at 60mph. 2. Restrictive exhaust. The std downpipe was designed to work with the std T3 so that should be ok. Also did this on my car. 2.5" press bent wouldn't boost past 10psi no matter what I did. 3" no muffler immediately went to 25psi+ I don't think running slightly rich will have as much of an impact as these two things. Is the wastegate flap closing properly? To test this quickly just put a spring holding it shut. How are you setting boost to 14-15psi? 2 full seconds is a joke. My 650hp turbo spooled faster than that with the aforementioned crap wastegate spring. Dave

Turbocharger work on pressure differentials. You are both right. Hotter gases occupy more volume. In a given container (the exhaust manifold), more volume of gas results in higher pressure. Dave

Well since we're sharing. Here is a different/easier?/weaker? way of doing it. Step 1: Cut the front off the LCA Step 2: Cut the top off the LCA back 100mm or so. Step 3: Get some 25mm bar and drill and hole and tap it to 5/8" UNF. Step 4: Sit the bar into the channel and weld it down the sides. Looks something like this: Step 5: Flip the LCA over and angle grind a channel into the underside until you get to the bar. Then weld it up so the bar is now joined to the LCA 3x100mm points: Step 5: Weld the top back on and grind it nicely. Step 6: Weld some flat onto the front. Step 7: Grind away the **** and spray it black. Now looks something like this: Step 8: Spin up some spacers for the rod end to cross-member bolt: Step 9: Put them on the car: Other things you might want to do at the same time: Cut the rear castor-rod bush in half to get more thread on that side, then space out the inner side by 20mm or so to get some more castor: Mine ended up looking like this, needed the front bar to be `relieved': Dave

I just did the S13/Z31 rear disc upgrade on my zed (finished it and was on the way to the track 2 minutes later). I made my own caliper brackets (large chunky fuckers by welding two bits of plate together). The guy who I brought the calipers/rotors off had it on his car with a modified R31 caliper bracket which worked. Might be worth having a squiz? I now have access to a mill so after I've made up some nicer ones I'll give mine away if you wanted to have a look? Dave

Interesting.. the thread doesn't appear to explain why. Would someone like to clarify that? Is it because the pistons accelleration towards TDC is slower hence the temperature increase of the charge occurs more slowly making it less likely to detonate? Dave

Now now, I wasn't meaning to be offensive. But I don't like being called deaf when you're talking about and we're talking about

DAW, To be fair, this discussion is focussing on rod ratio effects. Not strokers. That was a sidetrack. We all appreciate your input into stroker L6s and what you've said makes perfect sense, its just not what we're talking about. Dave

Agreed. Dave

Ta.