dangerous brain Posted April 15, 2006 Share Posted April 15, 2006 OK now I'm a bit surprised I fitted a boost gauge today and lo and behold the 1.0 bar of boost or more I thought I was making it turns out I'm not. Defi boost gauge is showing up 0.65-0.7 bar of boost at peak. Question is how the hell do you produce 365 bhp at the fly on that kind of boost? At 0.8 bar the car is supposed to only produce from the factory an argued 320 bhp. Also with a no back box exhaust should the car not be running more boost than that? I would seriously doubt the power figure from the dyno but all the other cars there that day pretty much made the power you would expect from them. In fact 2 of 10 were quite a bit below. 1 so much so he had it put on again to confirm it. So the forums open how does a car produce 365 bhp at less than stock boost? And no its not got a hugemungous single turbo Quote Link to comment Share on other sites More sharing options...
Getrag Posted April 15, 2006 Share Posted April 15, 2006 Full specs of the car, power wise? Quote Link to comment Share on other sites More sharing options...
dangerous brain Posted April 16, 2006 Author Share Posted April 16, 2006 from what I know Totally free flowing no boxes exhaust pipes 1.75"x4 FMIC And not a lot else performance wise that is obvious Quote Link to comment Share on other sites More sharing options...
milocoon Posted April 16, 2006 Share Posted April 16, 2006 Faulty Boost Gauge maybe or a leak / blockage in the line making it read lower than it really is ? If the Dyno is consistent with other cars then all your car mods should make it boost higher as you have said. Quote Link to comment Share on other sites More sharing options...
Tom S Posted April 16, 2006 Share Posted April 16, 2006 DB, is this the Green monster we are on about...... Quote Link to comment Share on other sites More sharing options...
JohnA Posted April 16, 2006 Share Posted April 16, 2006 ...Question is how the hell do you produce 365 bhp at the fly on that kind of boost? At 0.8 bar the car is supposed to only produce from the factory an argued 320 bhp...... So the forums open how does a car produce 365 bhp at less than stock boost? And no its not got a hugemungous single turbo Maybe now you see why some of us find such dyno figures entertaining;) So-called 400bhp supras struggling to do 14s anyone? Numbers are cheap, and punters will be happy and return to shops giving away fancy printouts. Who wants to pay money to hear the truth? Spend money on 'performance' parts and 'specialised' labour and then not have bragging rights? Does that make commercial sense? If you want half-decent comparisons, find a quiet stretch of road and get yourself an accelerometer. All will be revealed eventually. Quote Link to comment Share on other sites More sharing options...
lambertpig Posted April 16, 2006 Share Posted April 16, 2006 or get some real speeds noted on certain roads between 2 points after all im more interested in how fast the car will move than what it makes on the dyno.know of someone with a vauxhall vx turbo thingy which has 283bhp which would beat any roadgoing supra up to 110mph(ok i wouldnt fancy doing 180mph in it but) Quote Link to comment Share on other sites More sharing options...
hadyn Posted April 16, 2006 Share Posted April 16, 2006 Its the drag strip that never lies kids Quote Link to comment Share on other sites More sharing options...
dangerous brain Posted April 16, 2006 Author Share Posted April 16, 2006 I have an accelerometer I can use. Yes its the green beast matey. And its now not for sale anymore until I can sort this issue out. Obvioulsy people aint happy about that but I can't sell a car I think theres a fault with. This dyno figure I realise is probably a bit on the high side as are they all but power on the 2JZGTE engine is very boost dependent and to see a higher figure than you expect on a low boost setting doesn't make sense. The car does if I'm honest feel all of the supposed power. As stated an accelerometer check would help verify the dyno. The mods on the car would suggest it would boost higher than it is. Also the fact that before I did the top speed delimiter the car was displaying classic boost fuel cut symptoms Quote Link to comment Share on other sites More sharing options...
dangerous brain Posted April 16, 2006 Author Share Posted April 16, 2006 or get some real speeds noted on certain roads between 2 points after all im more interested in how fast the car will move than what it makes on the dyno.know of someone with a vauxhall vx turbo thingy which has 283bhp which would beat any roadgoing supra up to 110mph(ok i wouldnt fancy doing 180mph in it but) There was a modded monaro on the dyno straight after mine. It made the power figure it expected of it. Quote Link to comment Share on other sites More sharing options...
JohnA Posted April 16, 2006 Share Posted April 16, 2006 Its the drag strip that never lies kids yep, crank hp of 500hp and terminals below 110 should make one wonder:eyebrows: Quote Link to comment Share on other sites More sharing options...
dangerous brain Posted April 16, 2006 Author Share Posted April 16, 2006 So a 1/4 mile figure from a g-tech meter would be a good telltale? Quote Link to comment Share on other sites More sharing options...
dangerous brain Posted April 16, 2006 Author Share Posted April 16, 2006 Is this plumbed in the right place?? This is where the boost gauge tapping was plumbed in so I just replaced the greddy tapping with the defi one. http://showoffyourcar.com/cars/TOYOTA/15565.jpg Quote Link to comment Share on other sites More sharing options...
hadyn Posted April 16, 2006 Share Posted April 16, 2006 So a 1/4 mile figure from a g-tech meter would be a good telltale? Yes, but it'll never be a substitute for running down a properly prepped drag surface with accurate timing gear. Terminals at the end of the 1/4 indicate roughly how much power you're running. Have a look at this thread and you may well be able to work out bhp from using the formula: http://s14.invisionfree.com/hadyn/index.php?showtopic=211 Quote Link to comment Share on other sites More sharing options...
Alex Posted April 16, 2006 Share Posted April 16, 2006 Is this plumbed in the right place?? This is where the boost gauge tapping was plumbed in so I just replaced the greddy tapping with the defi one. http://showoffyourcar.com/cars/TOYOTA/15565.jpg I wouldn't plumb a gauge into there...the best place is by the MAP sensor on the intake manifold. Quote Link to comment Share on other sites More sharing options...
Branners Posted April 16, 2006 Share Posted April 16, 2006 Alex, can you track down a picture of where to stick it and then I can stick this in Technical for future reference? JB Quote Link to comment Share on other sites More sharing options...
Alex Posted April 16, 2006 Share Posted April 16, 2006 The blue hose on this picture is where I mean...I realise in this pic though it's not hooked up fully but this should give you enough info to proceed. Quote Link to comment Share on other sites More sharing options...
milocoon Posted April 16, 2006 Share Posted April 16, 2006 Nice picture, always found it confusing and wondered if you had a key to go with the photo or tell me the URL. Thanks Quote Link to comment Share on other sites More sharing options...
SimonB Posted April 16, 2006 Share Posted April 16, 2006 I wouldn't plumb a gauge into there...the best place is by the MAP sensor on the intake manifold. It should be fine where it is, although that's not he normal place, that's the manifold pressure reference for the BOV - should be the same. First of all, what was measured at the wheels on the dyno. What fudge factor was used to convert that to crank figures? Did they not hook up a boost reference and give you a graph showing that too? You'd expect that from a dyno run. Also, which gear was used for the run? It was converted to 6sp form wasn't it, so is 5th still 1:1 with the diff etc on there? If not how did they work it out, did they do a coast down? Always been very dubious of those. Quote Link to comment Share on other sites More sharing options...
SimonB Posted April 16, 2006 Share Posted April 16, 2006 Nice picture, always found it confusing and wondered if you had a key to go with the photo or tell me the URL. Thanks It's from the FAQ section of this very site! Quote Link to comment Share on other sites More sharing options...
Alex Posted April 16, 2006 Share Posted April 16, 2006 It should be fine where it is, although that's not he normal place, that's the manifold pressure reference for the BOV - should be the same. Yeah I know...but I just wonder if the BOV will cause dicrepancies...maybe it's leaking? Quote Link to comment Share on other sites More sharing options...
dangerous brain Posted April 16, 2006 Author Share Posted April 16, 2006 It should be fine where it is, although that's not he normal place, that's the manifold pressure reference for the BOV - should be the same. First of all, what was measured at the wheels on the dyno. What fudge factor was used to convert that to crank figures? Did they not hook up a boost reference and give you a graph showing that too? You'd expect that from a dyno run. Also, which gear was used for the run? It was converted to 6sp form wasn't it, so is 5th still 1:1 with the diff etc on there? If not how did they work it out, did they do a coast down? Always been very dubious of those. Yeah they did a coast down job. To be fair it was a cheapy power run on a group buy. They wanted the cars on and off quickly. It was only a social trip really with a power figure. http://www.westover.org.uk/si/power/brian1.pdf I think he did it in fourth ya know but with the aftermarket diff in it who knows where 1:1 is. So theres no chance I take it that the boost gauge take off is only reading one turbo pressure then? As thats the sort of boost difference I was expecting to see for that power figure. You are never gonna get 365 bhp at less than 1.0 bar in all reality. To be honest I was expecting double the boost figure. Quote Link to comment Share on other sites More sharing options...
dangerous brain Posted April 16, 2006 Author Share Posted April 16, 2006 OK top speed delimiter taken off. The car is now reacting the same at top speed as it does in this weird fault I am having. So its almost definitely a secondary limiter. Now how do i find the secondary speed input feed and adjust that like the primary? Quote Link to comment Share on other sites More sharing options...
tDR Posted April 16, 2006 Share Posted April 16, 2006 You can also use the line from inlet mani to FPR... most boost controllers suggest this line be used although some people worry about it interfereing with fuel pressure. Cheers, Brian. Quote Link to comment Share on other sites More sharing options...
Jake Posted April 16, 2006 Share Posted April 16, 2006 Bry, Isn't the question you should be asking; "How come my decatted j-spec 2jz-gte apparently only makes 0.7bar"? Quote Link to comment Share on other sites More sharing options...
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