mod list hey guys shoulda posted this this morning with my post but had to fly off to work, i realise you need good supporting mods and i beleive i have them supporting mods include aftermarket trust sidemount intercoolers nismo 555cc injectors hitec ecu ces 5 bolt dump pipes fidanza light weight flywheel underdrive pulley ported and smoothed exhaust manifolds ported and recoed cyclinder heads match ported lower and upper plenum nissport ported throttle bodies hks evc3 boost controller hks pod filter 2.5 inch aftermarket exhaust exedy heavy duty clutch thats why im thinking i either have a problem somewhere or the gt28r's just arent cutting it. if regards to uas's 400rwkw pull on gt28r they were not factory garrett gt28r's they were jap sepc s15 t28 ball bearing turbos which i believe to be almost identical to garrett gt28r but they werent straight outta a catalogue. i havent lost faith in the turbos yet and would really like to beleive that there is a problem which we are yet to identify why we are getting this power. below is a list of things that i think might be attributing please add others as well as commenting on how some of these problems might be contributing. * couple of boost leaks that i am aware of, dont know how serious but am trying to get them fixed 3 that i know off including one in the passenger side intercooler (leak from actual fin not where piping connects) *turbo actuators the ones used are from our stock t25 turbos i havd them removed and modified to fit which included having the shaft modified with a thread on one end so that we could wind up the tension on the wastegate spring they are currently both calribrated to open at 14psi. *hitec has not been tuned for new turbos, had a new eprom burnt which added more fuel at idle cos it was ideling badlyand added another 1 degree of ignition timing, road tested it and all a/f where were they were suppose to be. the car seems to pull really hard down low but when it gets up in the rev range seems to fall away as you can see from my dyno max power is reached at just after 6000rpm (6200 or there abouts) any other ideas would be greatly appreciated. jezza
its no good saying cams are the way to go, maximum air flow is determined by the entire inlet and exhaust sytem, upgrading one aspect is pointless, the way to do would be to get the heads tested on a flow bench and find out if the stock cams are holding it back, in my experience, cam's are one of the last places most tuners will go in search of a power increase, when dealing with modern 4 valve heads, its not like the old days
IMO Get rid of the Hitec and dont worry about burning chips. Get a stand alone power fc or similar that can be tuned properly for the whole map. Without knowing who did all your work and how well it was all done? its hard to say for sure but get a good brain behind those mods and I reckon you will be amazed at the difference. These turbos should and will flow more than you are getting providing everything else is in check. Even stock turbos can nudge 280RWKW on high boost with forged internals. My car pumps out over 300RWKW on nitrous with stock turbos and internals running 14psi (fresh virgin engine though) I defiantley think once you get a good computer controlling everything and a few good hours on the dyno tuning it and sort the boost leaks you will get there.
I agree with Jason, your weak link is your ECU. you need some sort of fully programmable ECU, then I believe you will find your power.
Hello Hello are you listening ??????????????????? Regardless of what you do anywhere else in the entire air flow system through the engine. It is limited by the choke point. I can tell you now, It is the cams and the maximum lift available with the stock cams and valves. case and point 1. Look at 90TTZ installation everything to be done has been done with the exception of the cams. 270 or so RWKW case and point 2. Jezza, everything has been done except CAMS. 270 or so RWKW Case and point 3. UAS slot car version 1 , stock engine, but high lift cams. and bigger valves. Most things more or less the same as the first two. 400RWKW !!! Further this is supported by recent builds with GT28R's in the USA which are making significant power as per the slot car. Please do some research before saying the answer is everything else. Because people seem to be unable to search for the TT net links I pointed too I will find them for you and link them in another post. This is all fact, not bullshit and has been tested to death in the US. Just a shame people don't research or listen before shooting from the hip. Lastly, The stock ECU correctly tuned (via hitec on a dyno or via the zemulator and a dyno) is as good as an aftermarket ECU (probably better) and has been proved to be enough for 700 RWHP. Here's the TT net link. Read it and learn. http://www.twinturbo.net/net/viewmsg.aspx?forum=general&msg_id=1658653
hello hello........ dont durn this into a pissing contest, your reasoning is ridiculous and you "can tell me" this stuff with no supporting evidence. this is silly
Excuse me !!! read the link and come back when you understand what it is saying. So far you have offered NO evidence at all about why. No theories apart from saying "its not the cams" This is done and done ! read it and learn. Until the limiting factor in the system is the turbo not being able to pump any more air. The system isnt optimized. In a properly optimized system you will not be able to develop more power as you will get to the point the turbo is maxed in airflow. When that happens pushing more boost just develops heat
lol. read carefully my posts and tell me where i said " its not the cams" i said i have not seen any flow bench testing which suggests that the cam lift is a drastic choke in the system like you say. you will also notice that none of my opinions are as definitive as yours. as i said earlier, before i would buy cams i would adjust the valve timing on the standard cams anyway,
Another link related to this for your reading pleasure. http://www.twinturbo.net/net/viewmsg.aspx?forum=general&msg_id=1658653 FYI, I get short tempered about this stuff because (and maybe you dont know this or havent seen it before as you are pretty new here. In which case I am sorry I came down on you so hard) This has been done over and over again and again. A thousand questions posed and answered going right back to the first GB I ran for the GT28R's over 18 months ago when they first came out. If you care to PM, JP at UAS he has all the figures for head and valve flow for stock and modified, and has posted them here quite a few times. The stock CAMS ARE a major restriction. This is why I state it as a fact. Rather than agree they should be tested. This is known, not speculation. If you do a search you will probably find the results burried under layers of UAS info on the slot car development over the years. The answer for Jezza's problem isn't unknown at this point. It just needs to be embraced. There is a limit to any turbos you retrofit to this engine and its because of the modest lift of the cams.
Dynos ain't Dynos My car 'supposidly' made 275 rwkw according to a dynapack chassis dyno at 1bar, on the same token it was 'actually' making around 235 rwkw on a dyno dynamics roller dyno.
I am sure you could adjust the cam overlaps to get a bit more top end power. But it will be at the expense of midrange torque. I think i would go with the extra midrange torque.
Here is another related link that should be read if people want a better understanding of the dynamic's of applying those turbos to your engine. http://www.twinturbo.net/net/viewmsg.aspx?forum=general&msg_id=1656975 Greg Dupree is a guy that should be listened to. He is very cluey.
i understand what you are saying graham and it makes sense, however what i am interested in is that icer's car on the exact same dyno with the same conditions can crank out 25odd rwkw more with td04s than gt28r's and i dont beleive he has gone to the trouble of porting exhaust manifolds and heads in fact i think it is safe to almost say that my mods list is a little more extensive yet at the end of the day the td04's seems to be a better match and make more power than the gt28r's now i havent got the compressor maps for the td04s and i am not very good at understanding it all but the td04s are rated at 400hp to 500hp and the gt28r's are similar at 400hp to 560hp (range 200hp to 280hp per unit given in garrret catalogue). so with both cars been similarly modded (same ecu, both larger injectors and coolers) the dyno tells me the gt28r's dont make as much power and suit the vg30 as much as the trust td04s do. however i am not taking into account my boost leaks but icer also had a boost leak when he made his pulls.
Your issue is over 6500 revs Jeremy. On a car that has the system optimized, your power would not fall off over 6500 revs like it does. If you project that curve out to 7500 you have made over 300kw !! Your car reached the choke point of the amount of air flow it can pass. This can only have higher power with more boost (which generates more heat) or freeing the system of air resistance. Why isnt Icers DYNO on the list? I think you will find his just didnt drop off quite so much after 6500revs to get the figure he did. I havent seen the compressor graph of the TD04 for a while. But I vaguley remember it is a slightly bigger turbo and has a lot more lag. More like a GT28RS! The TD04 is horrendously more expensive than a GT28R as well. The GT28R was always a turbo that was an upgrade replacement for the stock one with similar lag. Maintains drivability and gives you a better top end than stock. The TD04 has MUCH more lag. It was never meant to be a dyno killer. But having said that, It can still be effective. But you have to refine the air flow through the system to let it attain its best. Which is to max out its air flow capabilities, making the turbo the choke point in the system. The graph would be A LOT different with the top end continuing to extend up to 7500 revs if this is done. Peak power should ALWAYS be at peak revs in turbo cars if everything is correct. Are you even sure those old wastegates are not creeping? No one mentioned your boost level and Icers. Its a bit hard to compare without it. BTW match porting makes a very small difference. but i would say your manifolds ported are a good upgrade.
The stock cams are a big restriction because of their shitty lift. The extra ~1mm that most aftermarket cams give you makes a HUGE difference. The duration really only has a small effect on the power, it's ALL in the lift. Same can be said with one test the guys in the states ran on ported stock manifolds, from memory, modded heads were flowing more at .1mm lift than stock heads at .4mm lift with quality exhaust manifolds. ZisLuv knows what I am talking about. Valve size can actually act as a restriction, I personally believe bigger valves only work on old single (twin) valve heads, not heads which already have 2 valves. I do agree that you need high lift cams in order to make good power quickly without having to use stupid amounts of boost. I had a book which covered tests on many different engines and really, the type of engine meant little in regards to test results. Lift and valve grind was what made all the heads flow well, valve size actually only increased flow on some heads slightly and restricted/didn't change flow on others. It went into such technical detail that I doubt anyone here would really understand what was going on in regards to cam duration etc, but the results were there.
Ok............... ......the guys that tune my Zed (Milanco Pro Dyno), use a Dyno dynamics You can see the chart on OZ300ZX.com The forum name there is The Red Baron.
You have to amke sure the dyno is calibrated for the proper atmospheric for the day also you can dyno your car 1 day and the next same dyno and settings and get different readings. Also there is two types of dyno isnt there. 1 is a braked type inertia dyno and the other a plain roller dyno that offers not much resistance only incline. I would imagine the later would show more power as there would be less resistance to the power output. Do you think thats correct any thoughts all.
The other kind is the 'hub dyno' I made 260-270kw at 1 bar of boost on stock turbos, stock engine (lots of supporting mods but engine itself untouched) and stock fuel injectors. 301kw on the hub dyno. I accept the 260-270 I was getting on the UAS dyno though. With GT28RS have reached 401kw at 20psi on UAS's dyno. btw the cams are reground and would have had far less power if they were left alone. Definatly recommend doing this. Not even expensive to do if you dont want the 'wild' replacement cams. If you have other mods and only make 250ish at 20psi with bigger turbos then something isn't right. If you cant find anything wrong, try another dyno?
Not that it's important for the outcome of this thread but my power figure was before I have the UDP and the FMIC installed.
