Brezza

so what you're suggesting is that because the cams allow more flow through the head = less pressure/resistence in the plennum for the same volume of air? so that might explain why its making 360kw on 20psi (with cams) instead of 25psi (without cams)? same volume of air passing through the motor, just less resistence in the plennum? and if the intake isnt sucking closed or causing a restriction before the turbo, then the restriction might be after the turbo? maybe intercooler? (but its a 70mm ARC cooler so it should flow pretty well) and there were no signs of intake temps spiking higher on 25psi. there shouldnt be a restriction in the head, because its obviously allowing more flow, because its pushing 360kw @ 20psi whereas before it needed 25psi to get 360kw. -5's should in theory be fine to flow 25psi with everything else allowing them to flow that much? so the flow is either getting choked at the manifolds pre turbo? or its getting choked after turbo (dumps) unless anyone else can shine any light as to why i'm not getting any real gain from an added 5psi? the extra 5psi wouldnt be enough to cause valve float would it? and would valve float cause the symtoms i have?

there is no cat on the car i think the front pipe is 2.75 from each turbo then merges to 4in and its 4in from there all the way back. the manifolds weren't port matched. the manifolds havent been modified in any way.

when he was playing around he added another 2 degrees and it made no difference to the power output. basically the gains when first tuning at 20 psi were good, but it seemed changes to the tune at 25psi had little to no effect. you could see on the AFR where if it were running leaner, the power would still be the same. and timing changes had little effect at 25psi either.

Sorry, i was trying to make a joke. i'm not running a cat. united E85 it wasnt sitting in the tank for too long. only a week. so its not like it was in there for months.

i'll see if i can get the tuner to send me some of the dyno graph runs. the AFR's seemed to be okay, sitting around 14.4:1 on cruise then it dropped down to 12-11:1 on full throttle.

What's a cat?

hey guys, a little bit of back ground about the car, i've been chasing 400kw out of my -5 E85 powered GTR had issues with not making the numbers on higher boosts. so i've been making some small changes to see what the problem was. firstly i changed the exhaust from a 3in cat back to 4in and it made a 10kw difference. so then i change the cams from std to tomei type B's and this is what has happened: i had type B tomei poncams installed. with no cam gears. so cam timing is zero. i dynoe'd the car on std cams on 25psi and it ran 360rwkw put the cams in and had the tuner play around with the tune to get it right on the low boost (20psi) and it made 360rwkw. i thought WIN!! same power, more response and 5psi less boost. then once we were happy with the 20 psi pulling consistently between 360-365rwkw we went to high boost setting of 25psi. and a whopping big 365rwkw. it varied between 365-370rwkw on 25psi so in reality 5 extra psi made no difference. the low boost is great, holds boost well, and pulls right to redline. but 25psi is bad, the boost waves around a little and it seems like it just wont flow? the tuner seems to suspect that its got something to do with the std manifolds not flowwing enough. its a big job to change over the maifolds, i was thinking if i did that i'd change the dumps to 3in too. i've also had the system smoke tested and pressure tested to rule out any boost leaks, just to give a recap of mods here they are: forged pistons std rods R33 GTR crank 260 degree 9.15mm lift cams -5 turbo's mines dump pipes (look to be 60 or 65mm) 2.75 in front pipe into 4in cat back std manifolds silicone intercooler hoses ARC 70mm intercooler K&N air filter in STD airbox 1000cc injectors (siemens) nismo AFM's nistune ECU twin in tank pumps E85 e boost street boost controller we've tried opening up the airbox, we jammed a screwdriver to open it up and that made no difference the ECU and tuning ware responds to changes so it isn't the software, or electronics he said that it doesnt look like the hoses are sucking closed because you can see the power just cut off when it does that and it doesnt do that. the power just follows the same curve doesnt matter whether its on 20psi or 25psi the intake temps weren't rising too greatly, so the intercooler is doing its job. the tuner tends to think that it's more of a mechanical thing like there being back pressure in the manifolds or dumps & turbo's which isnt allowing the air to be pushed out the engine and is just raising the boost because there is resistence in pushing boost into the motor? please help, if anyone has any idea's as to what it could be or experience of similar results?

Okay, i've had some further changes made on the GTR i had type B tomei poncams installed. with no cam gears. so cam timing is zero. i dynoe'd the car before the cams on 25psi and it ran 360rwkw put the cams in and had the tuner play around with the tune to get it right on the low boost (20psi) and it made 360rwkw. i thought WIN!! same power, more response and 5psi less boost. then once we were happy with the 20 psi pulling consistently between 360-365rwkw we went to high boost setting of 25psi. and a whopping big 365rwkw. it varied between 365-370rwkw on 25psi so in reality 5 extra psi made no difference. the low boost is great, holds boost well, and pulls right to redline. but 25psi is bad, the boost waves around a little and it seems like it just wont flow? the tuner seems to suspect that its got something to do with the std manifolds not flowwing enough. its a big job to change over the maifolds, i was thinking if i did that i'd change the dumps to 3in too. i've also had the system smoke tested and pressure tested to rule out any boost leaks, just to give a recap of mods here they are: forged pistons std rods R33 GTR crank 260 degree 9.15mm lift cams -5 turbo's mines dump pipes (look to be 60 or 65mm) 2.75 in front pipe into 4in cat back std manifolds silicone intercooler hoses ARC 70mm intercooler K&N air filter in STD airbox 1000cc injectors (siemens) nismo AFM's nistune ECU twin in tank pumps E85 e boost street boost controller we've tried opening up the airbox, we jammed a screwdriver to open it up and that made no difference the ECU and tuning ware responds to changes so it isn't the software, or electronics he said that it doesnt look like the hoses are sucking closed because you can see the power just cut off when it does that and it doesnt do that. the power just follows the same curve doesnt matter whether its on 20psi or 25psi please help, if anyone has any idea's as to what it could be or experience of similar results?

how come it's got such a good spread of power?? what's been done to this, i havent seen a power curve like that for a turbo motor before?

Well hopefully a smoke test can show if there are any leaks anywhere and when the cams go in the clearances will be checked so that should hopefully rule out anything to do with the head? it very may well be a leak somewhere. the car made less power when i changed my intercooler piping. i made 350kw on 21psi on PULP then changed my piping because the stock one blew off and split. replaced it with a silicone one and it made 315-320kw on 21psi. so it very well may be a leak somewhere in the I/C piping? maybe just enough to be bleeding out a slight amount of air?

I've still got std cams, which might be holding it back a little? will be putting some type B poncams in soon, and will get smoke test done. hopefully be nudging 400kw if everything is right.

where are the common places for leaks when a smoke test is done?

i probably should get a smoke test done on my GTR. that's the only thing that i havent tested it for. i had issues with the idle searching, then i had the tuner block off the hoses going to the idle control valve under the plenum and i picked up another 1.5 of boost on the same settings. i think all my hoses probably havent been replaced yet, and its an 89 GTR so pretty old hoses.

Seems about right? i'm making 372rwkw on 24-25psi on E85 with -5's the only restriction would be the turbo's E85 won't make turbo's automatically make 50rwkw more top end that it would on PULP. E85 gains are in the midrange, so you might've only made 317kw but the midrange would be a lot stronger than most others in PULP

all you can really do is put an alarm and imobiliser on the thing. don't park somewhere dodgy and hope and pray it never gets stolen. and obviously insure it if it does unfortunately get stolen.

i think it will go bang! no offence, but i doubt that you'll be able to push the -9's past 350rwkw (you'll probably have boost control issues especially above 24psi) especially on a stock motor, i think you'll find that it'll probably spin a bearing

Lubemate did it, he mainly gets the bulk of his work from industry but he does do analysis in bikes and cars. from memory he just told me to take a sample after the car has been running, it didnt nessecerily need to be at temp. just run it enough to ensure that the oil wasnt all settled, (a good indicator is the oil is warm to the touch, not scalding) i gave him 2 samples 1 from the oil coming out of the sump (not scooped from the pan) and another container of the clean oil i was putting in. (obviously has to be the same type of oil as you put in previously)

get an oil analysis done. i got mine done, cost me $40. i changed the oil out at just under 3,000kms because i thought it was getting a little too thin. but turned out that the test came back really good, no bearing particles found or ring particles found and the oil viscosity was within range of the fresh stuff i sent to be compared with. and i was using Motul 8100 Excess 10w40

+1 the stock water temp gauge is rubbish! i have after market gauges and they went off at 105 degrees for water temp and when i pulled into the pits the coolant was boiling in the overflow. the stock gauge still was in the middle! so it really goes to show its useless! the stock guage will be in the middle at 40 degrees right up to over 100degrees. if your stock guage moves above halfway its already too late, you've probably cooked the engine.

I would say that 110 is probably where you should maybe have a cool down lap? it depends on the day too, if its hot the car is going to run much hotter. i find that when my oil starts getting above 80 degrees the water temp starts rising quickly too, my gauges have warnings and they were going off last trackday when i was boiling the coolant. i had to put it in the pits and pour water over the radiator. this was a pretty warm day in November, but other days i have been out there for a full session and had no temp problems. i try and just use a rule of thumb that if i'm going near 100 degrees i should back off and cool it down, because if your oil is near 100degrees the water is going to be pretty similar. they both flow through the block, its just water transfers heat better than oil and warms up quicker.

the tune was changed, the tuner had to add a little more fuel higher in the rpm. also there was a problem with the boost fluctuating which needed to be fixed. the boost controller was too sensitive and even with the settings changed the wastegates swing arm needed to be modified to not move as much when the actuator opens the gate because the turbine would slow down too quickly when the gate cracked.

there is an issue of missfire at high rpm, i have to take it back to get my poncams installed when they arrive and a retune will be done with them on there. i dont know if the timing was touched, i remember him saying that the top end needed a little more fuel because it was running a little lean because of the extra flow but appart from that it was fine. next time i head around there with the cams ready to go i'll get him to print comparative graphs of the 3in exhaust, 4in exhaust and 4in exhaust and poncams. and that should show all the differences of all three. this probably wont be done for a while since i have my wedding in 2 weeks and honeymoon shortly after that. also its probably not worth pushing the car mega hard on the dyno with all this hot weather we're having.

nah, not yet. i've only just been told over the phone. will be picking the car up either tomorrow or friday.

Results are in! I've been told that the car made 372rwkw @ 25-24psi the boost peaked at 25psi and trailed off to 24psi last time it was dyno'd at the same place it made 364rwkw @24psi but on a mainline dyno it made 353rwkw @24psi so read into it what you'd like. obviously factors such as air temps will effect the power produced. but this is making no changes other than going from a 3in cat back to a 4in cat back. ( and a tickle to the tune to ensure that mixtures are correct) all that was needed to the tune was a little more fuel in the top end. i suppose its not bad considering its still a STD cam'd engine. will have to see what happens when the Type-B poncams go in.

okay, time for an update the tuner ran the car up on the dyno yesterday morning. it made the same power on the same boost, but he ran into a small problem with the boost controller. the boost doesnt seem to want to hold, waves and varies by 3psi. he said before the boost starts to wave the curve looks like it should be heading towards 370kw they're going to modify the swing arm on the actuators to try and get the boost to hold a little better. i do recall the car feeling like the power does feel like it cuts in and out. only when high in the rpm range though and its worse higher in the gears.