The Alchemist

R32 GTR rebuilt engine with all the usual support mods etc etc Airflow improvements: Tomei cams 260/260 9.2mm lift HKS cam gears set at -4 exh/+4 inl Garrett -5's turboes with HKS split dumps HKS Super Drager exhuast system with no cat Flowed and ported head ( work of art actually ) Greedy inlet piping kit, Trust intercooler and piping kit 8.8:1 compression 0.5mm over forgies PFC computor tuned with FC Datalogit by myself > awesome software a must have! RB25 AFM's Run up on a 2WD Dyno Dynamics Dyno: Boost running at 17psi > 311 RWKW Boost running at 19psi > 365 RWKW or 488 RWHP Torque 7200N at 19psi in 4th gear Full boost reached at 4000 rpm, very responsive ! All this with a 8.8:1 measured compression ratio on 95 Octane fuel. Fuel burn breaking down at 20psi and becomes unstable resulting in much less power. Will get some race fuel and try again at 20+psi and see what happens. Will post dyno graphs soon:

Hi, with poncams, dumps and -5 garretts, similar specs to N1's, I reach full boost (17PSI) AT 4000RPM. Before cam adjustment it was 4300rpm. They were already pretty close from the old engine and that was moving the intake only 2 degrees. That 300rpm on the road, though, translates into hugely improved spool up when over 3000rpm. Very worthwhile addition to the driving experience Mike

similar results with the cars we have done with standard cams and turboes etc. Worth doing in my opinion. Even better results with a set on poncams though. Perhaps time to maybe re-educate your tuner Mike

When you change injector sizing, for what ever reason, you will need to have the map touched up to suit as the change in size can affect the fuel delivery slightly at certain loads and RPM. The touch up is a quick affair that would only take an hour at the most. BUT, if you're not fussy, you can get away with no changes whatsoever. Its up to you. In other areas such as startup fuel and accel pump fuel, these settings are in injector ms times and ARE NOT CHANGED WHEN YOU RESCALE THE INJECTORS !!!!. That lovely puff of black smoke, even on light throttle changes is the accel pump fuel and with larger injectors like 700CC can be a cloud of black smoke at the lights. The PFC settings for accel pump fuel are around 4.5 to 5ms standard and with larger injectors I have reduced these times to about 1.2 to 1.5ms with no black smoke and perfect throttle response (actually got better the more I reduced it) . Fuel usage also reduced dramatically. Hope this helps, Mike

I use the FC Datalogitsoftware and find it excellant. Can't comment on the APEXI but I guess it would be just as good mate..... Ham or Eggs?

Just to upset you all further, lol, we had a car make 477rwkw on our dyno dynamics dyno, often accused of reading too low .... yeah right rb25 head rb30 bottom end, head majorly modified for flow with epoxyed ports and big cams etc etc running a 3540 with the 1.06 exh housing and all supporting mods running a haltech ECU. The car is an absolute weapon! Not sure if it was on PULP but can check. Will also get the dyno graph to show you all. Couldn't believe my eyes actually but "hey" I was there and thats what the dyno said Fuel usage logged on the haltech at the 11.5:1 AFR matched up with calculated power figures too. Thats always a good guide to use. The laws of physics don't change after a good arguement eh? Mike

Hi, I would be looking at your dwell time. Run it under load on the dyno and put an amps clamp around the neg trigger from the coil back to the ignitor and check that your coils are fully saturating. Do a google search for "coil saturation" and you will find plenty of scope graphs showing what this means. Splitfires do seem to have a slightly longer charge time so if you haven't adjusted your dwell time accordly your coils may not be being charged fully. This compromises the coils ability to fire a spark under high load or peak torque conditions. If you have a PFC and the datalogit software dwell time is able to be changed to suit. If however, you have the hand controller you are stuffed as dwell time is not an option with the hand controller. I just saw you have a series 2 with no ignitor..... put the amps clamp around the 12v positive wire to the coil, this should still show the amps each coil is drawing and its charge time Hope this helps, Mike

I run them in my engine and they seem to go round and round ok..... Get a good tune with no knock or detonation and this keeps the load stress down on the rods and the pistons. Thats my 2c. Mike

Pair of HKS GT-SS Turboes for sale. Suit any RB26 DETT. 3000km since brand new. Selling due to upgrade, surprise surprise $2500.00 NZD plus freight from NZ to Aussie. Does not include dump pipes or gaskets etc etc, just the turboes. All enquires please reply to this post. Cheers, Mike

I have a HKS super drager on my GTR and its great, highly recommended. quiet as at cruise at 100km with ZERO drone. Yet wind it up over 5000rpm and it howls like a banshee

I increased my compression ratio to 8.8:1 on my GTR rebuild. I run it on our piss water 95 Octane here in NZ with no problems on 18psi, with tuning to suit of course. It makes 285 RWkw on a dyno dynamics 2WD dyno. Lag is not in my vocabulary. Comes up on to boost like a bloody rocket ship and I contribute the higher comp ratio for this when compared to other GTR's I have driven. Mike

I agree with REV210. Having worked on several GTRs with GT-SS some with std cams and some with TOMEI Poncams and tuned them as well the GTR with the TOMEI cams will win hands down in almost all respects. Well worth the money. Results like REV210 stated above agree with my experiences The most noticible thing is the torque holds dead flat almost to the redline whereas with the std cammed GTR the torque drops off over 6500rpm. These are the cams the GTR should have had from factory

Hi, I've removed the plenum on my own car 3 times looking for air leaks found it between the manifold and the cylinder head gasket in the end. Anyway, its a do-able job with a few slight catchs you need to know about. The main one being a nasty little 10mm bolt holding a bracket to the underside of the plenum right at the back between 5 & 6. If you don't know its there you'll wonder why the hell the plenum won't come off. Also I bought a curved 12mm stalwille spanner which makes getting the lower plenum nuts a piece of cake vs using a 12mm on an long extension....... good luck Mike

personally I like a good backfire on a gearchange or decel but " hey" thats just me If you find it a problem there are a couple of things you can change on your PFC settings to remove or lessen the effect. Firstly your accel pump settings are set quite high from factory with the PFC. So any slight blip on the throttle pumps in a fuel but little air. This hits the hot exhaust with the usual pop pop crack sound. You can even "make" it do it on a trailing throttle by tapping the throttle lightly on decel. Dropping these accel back from the 4 or 5 ms factory down to 2 or 3ms improves things. Secondly the bottom fuel row settings have a big effect on trailing throttle overrun and can by reduced (carefully) to reduce exhaust popping. The PFC does have fuel cut on overrun I know but these bottom row settings do have an effect. Cheers, Mike

Well I have 700CC injectors and dialled my Accel pump setting to 1.5ms at 1000rpm down to 1ms at 3&4000rpm, much better and no black puff or cloud when I drive away. The setting is best felt by the driver on the road of course but with only gentle acceleration. The bit you're feeling for is the very initial push as you just open the throttle. Slaaming the throttle open especially at rpm under 3000 allows you to feel no change regardless of setting. Zero them out and gradually increase them and you will see what I mean. Mike

need a diagram really to properly explain, if you do a search for Cams + "lobe center" on google you will find many sites showing a couple of cams set up with a circle 360 degrees around it and a centerline drawen down the middle of each cam lobe 2 the center of the circle. The angle between the lobe centers becomes an obvious thing. The smaller (tighter) the angle is the more the cylinder head will tend to flow better at higher RPM. Its to do with the decrease in time allowed for air to pass through the head as RPM increases you see. This increases the overlap (the time the inlet and exh valve are open for at the same time) which allows more air at higher RPM to pass thru the head. Complicated eh Anyway, small changes of a degree or 2 can have a substantial effect on the way the engine produces it torque and where it produces its torque. Using factory cam settings as per the timing marks with adj wheels on zero zero, the lobe centers tend to be too wide at say 114 degrees which is why you read about everyone adv the inlet and ret the exh which tightens the lobe centers and improves turbo response and overall torque. A good thing. The problem is that the other important cam setting is the overall relationship between the cams and the crank. Once you get the best lobe center angle you can move on to the adjusting the inl & exh cam together either advancing or retarding them. This moves the torque curve up the rpm or down the rpm range. All fine tuning but all worth it in the long run. Don't get to keen on the light and mid load tuning either cos this all changes when you change the cam timing and often has to be done again Mike

Has had problem since the owner brought it several months ago. Many tanks of gas later Thanks for the reply....

At idle and free reving, unfortunately we don't have a 4WD dyno to run it up on..... Does anyone know more about the fuel strategy and limp modes on the R34 GTR'S and what activates them...

Situation: workshop with good experience with Skylines and all their associated problems. Has Nissan Conzult software and 4 channel scope. Vehicle: Untouched R34 GTR with 55,000km on the clock. standard everything!!!! Problem: running rich like you wouldn't believe at idle and light throttle cruize. Work done or checked: New Air filter, cleaned AFM's, replaced one dead O2 sensor ( thought we had it but no )dropped exhaust to check for blockage, return line off the fuel reg into bucket to check for return fuel line blockage > ok, New plugs, new coils, checked and flow tested injectors > Mint, checked fuel pressure > mint, checked TPS sensor > mint, checked factory blow off valves for leaks etc etc > mint. Used a can of brake cleaner looking for air leaks > got high but no leaks found. No fault codes, reseting ECU makes no difference. Checked fuel pump voltage regulator function > mint. Checked factory ECU for any mods > none. Losing many hair follicles by this stage. I believe all we have left is the ECU but this would be a rare fault. Has anyone had experience with a R34 GTR with this problem, I realise the ECU is a much more clever unit than the earlier R32,33's and I think its almost like the engines going rich like a fault condition exists between sensor inputs making the fuel settings pig rich for safetys sake but I'm buggered if I know what. Only odd thing is that the car goes fine when cold in the morning for the 1st 10mins then it all goes belly up once its warmed up. Any ideas? Mike

Accel pump settings are set high on a PFC. The setting is in Milliseconds, so if you change to a larger injector they will be way to big making the problem worse. And "no" the accel pump settings are not scaled when you change the injector size settings in the PFC. This setting can give you the big puff of smoke when you first accelerate and cover the back of your car with black crap. This puff should clear quickly to no smoke on gentle acceleration providing the rest of the tune is good. Mike

hey there mate, your boost control has too much sensitivity setting I'd say. Sort that out first as Nismoid suggested. The upper power drop off you see there seems to be fairly typical with the SR20, at least the ones I've seen/tuned on the dyno. Cam lobe center angle seems to be the key with any cam gear tuning. The tighter the lobe center the better higher RPM flow & therfore torque will be. Unless you time the cam gears to the crank so you know the lobe center angle to start with, any changes will be a try it and see whats happens affair. Also can you post your dyno graph showing the torque please as this can be more helpful to see what is going on in the engine and its peak efficency point. Hope this helps, Mike

When fitting a new pump, especially, or when servicing your engine every 20,000 km change your fuel filter!!!!! very important, often forgotten and YES they do block up and don't last forever. We've seen a few lately thru work on "problem cars" no one else can fix etc etc and the damn fuel filter was stuffed. A trap for young players, too, is that the fuel pressure can "look " ok with the usual inline tests but the flow is whats missing. Perhaps fitting a new grunty pump only masks what is a simple problem?? ..... mmmmmmm Hope this helps, Mike

One of many reasons for this Often its the O2 sensor that has failed causing the Air fuel Base which is sort of a "learn" function in the factory ECU to alter to a positive or a negative change in the amount of fuel delivered at any given time. As an O2 sensor can fail giving a high or a low or an "in the middle" voltage flatline the AFR Base can trim the fuel in varying ways with often more variable results in the real world. This is why an ECU reset can "fix" the problem until the ecu RELEARNS again and stuffs everything up once more. This causes havoc at idle and lean cruise and causes many of the idle hunt and fuel economy problems that plaque skylines. hope this helps, Mike

unplug your idle control solenoid and screw all the way in the course adjustment screw on your ICS and see if the idle drops any, if at all. If it doesn't chances are the gaskets between the throttle bodies is broken when they removed the plenum or they have left one of the many vacuum control tubes and feeds off altogether or split one of the hoses while removing them etc ect etc. Such a leak bleeds into the common vaccum rail and thus feeds all cylinders and upping the idle as has happened to you. try that mate.. Mike

had a GT3540 0.82 on a standard RB25 with fuel support mods only and Link ECU. 12psi boost by 4900 rpm. Very laggy on the road. Horrible to drive with on/off power extremes. yuch Mike