The Alchemist

well I have a set of HKS GT-SS plus dumps sitting here in a box but am waiting and saving to do a full engine rebuild first to complement the new turboes. Its just that I hear SK and many others saying stuff like "250rwkw" on GTR's with similar mods and I'm wondering what I'm doing wrong. Tests were done on a dyno dynamics in Shootout-6 with proper testing protocols and atmo comp set up correctly. The cars makes 5000N by 3600rpm and holds this till 4800rpm where it slowly drops off to around 4300N by 6200rpm. The torque curve looks narrow to me thats all. Mike

Hey SK, I've installed Tomei's in my R32 GTR and found that the torque starts to drop off at 4800rpm leaving me changing gears at 5000 to 5500 rpm cause of noticible seat of the pants dyno torque loss. Its very obvious on the dyno runs too. AFR's are all good and the timing is tweaked to get the best out of it, 191 RWKW at 14psi at 6200rpm. Theres also a bit of boost creep over 6000rpm up to 16 psi due to possible restriction in the turbine side Is it time to try retarding the cams to help bring up the mid range and top end again ? What would you suggest> -2/-2 and see what you get? or increase the lobe centers to try and broaden the torque band with a -2 inlet +2 exhuast? When doing these changes should you take out a couple of degrees timing for safety reasons when experimenting? Other mods affecting flow incl steel wheeled GTR turboes with larger comp wheel only, HKS super drager exhaust, trust intercooler, std AFM's ( reaching 5V at 6200rpm ) std dumps Cheers mike

mine does it as well although my cams are set on "0" on my degree wheels, which means very little other than a starting point for which to gauge changes by. I stop it by simply changing down a gear and moving out of the surge line. Have you have it dynoed since the cam change? my torque starts to drop off after 4800rpm since I've installed the cams so I guess I will need to retard them to move the torque curve to the right a bit to get back the top end rush. I change gear now at 5000rpm cause the torque drops off so much after that. Mike

Well I have just dynoed my R32 GTR on a DD Dyno and got 188kw @ wheels at 14psi 6000rpm. [/u] Mods for power include: Steel turbine and larger comp wheel (mild upgade) on GTR turboes, Tomei cams 260/260 and a trust intercooler. Forget all the support systems for now blah blah blah I was in shootout 6 mode with atmo compensation "on" and correctly setup (thank you dick smith weather station) At this level of mods my air flow meters are reading 5.1V at 6000rpm and I have major boost creep due to the turbine side and/or waste gate being to small. Boost although set at 14psi creeps up to 18psi by 6000rpm so I don't rev it any further than that. I continually find it amazing, as I was the dyno operator on my own car, how people seem to get 200+ kw on near standard turboes and seem to suffer non of the above problems?>? The engine is in good condition with no air leaks and has good support systems in place. Mike

just trying to offer advice not scare people...this was MY experience only and YOU could have quite different results either better or worse for that matter...! Mike

you will almost certainly need to re-shim them depending on the age of the car and the wear on the original cam shafts. because there will be wear, you can't simply measure the clearences of the original cams then make the assumptions that when you fit the new ones that they will be the same. They almost certainly will not be. You have to do a dummy fit with the new cams then check all clearences, calculate any shim adjustments you may need to make> get any new shims you may need as a result of your dummy run, dismantle dummy run and fit new shims then recheck. This is a very time consuming process that took me and a fully trained nissan A grade mechanic 2 weekends to complete. I needed 11 new shims and had them made in a machine shop and heat treated to 50 rockwell hardness. Was well worth the result though with the engine now running very smooth with no valve noise as start up like I used to get cos clearences are all perfect. Boost ramps up by 3500rpm now and pulls hard to 5000rpm were I am now having boost creep problems due to excessive back pressure from the now restrictive turbine. It can't handle the air flow the engines putting through now so I am going to remove the turboes and machines out the little GTR wastegate holes into big holes to help the exhaust escape and minimise backpressure. So you see, cams are great but can cause other problems down the road. It seems the GTR was built to a certain spec and has limitations once you start pushing things along a bit .. Mike

hey Dayna...heard you got third? Is that right......Did u fix that miss problem you where having ?

mine shat themselves after 75000km went to split fires, compared them on a bench test to a known good RB coil and the difference was HUGE. The gap jumped by the spark was maxed out to 35mm, on the bench tester, and RPm wound up to 5000rpm and the thing was still sparking a big thick spark. Std RB coil couldn't hack it past 30mm and the spark was noticably thinner and weaker. Not to mention no more break downs under boost

look in boot at hicas computor, there will be a flashing red LED in one corner of it, count the number of flashes ( no long or short just a "flash") this is the error code. If more than one thing is faulty the next group of flashes will be the next error code then it repeats etc etc . Do this with the ignition in the "on" position....I don't think you need the car running. get back to me with your findings.....I have a copy of the error codes handy. Mike

I found that after doing cams, Tomei, that I got boost creep over 5000rpm and there was nothing I cguld do to stop it either. I have highflowed original turboes though which makes extra airflow again. The waste gates are fully open at 14psi and functioning perfectly, the waste gate holes simply can't pass the extra volume of air. Just my input. Mike

hi, load on cell 11...seems low to me are you using std AFM? What about turboes? what boost are you running? Is it a GTR R33? All these can affect what cell you end up in at certian boost levels? On my R32 GTR, std AFM's, highflowed GTR turboes, running 14psi I reach cell 15 on load by 3600rpm to give you an idea anyway. But remember that the AFM measure total airflow not boost (although thay are associated) and as I have larger comp/turb wheels my turbo may reach cell 15 at 14psi boost but yours may not if they are std GTR turboes. That aside please answer the above questions first and maybe myself or other here will have a better chance of helping.... Mike

settings "2" on the datalogit software, otherwise under "etc" or "settings" I think on the PFC commander, been ages since I've used it ....will check and get back to you. regards, Mike.

ditto ...try www.techedge.com.au I use this one and its very good/reliable/accurate/inexpensive but definitely not cheap

out of interest...what did you measure the 11.5:1 with ?

I run 15:1 at light throttle on my GTR no problem at all. 40 to 42 degrees timing No problem. Once over 3600rpm though I increase it to 14:1, still 40 degrees timing too. Boost> as per above posts I think your car has a problem .... Mike

Hi there, your problem could well be the O2 feedback...not that its not working properly but because your car may not like a AFR of 14.7:1 when at idle during warm up .....My GTR does the same thing and got even worse when I put cams in .....I leave it turned off all the time now as I have done a lot of work on Light throttle cruise settings and have a constant 15:1 now on light throttles. The o2 feedback, if switched on, comes into play once the engine temp reaches 70C on the GTR and this is when it starts the hunting. The temp for a GTI-R may be slightly different at which this occurs. During the 70c to 90c period the engine cylinder head is still coming up to operating temp during which time the engine would still be sensitive to a lean AFR of 14.7:1 and cause the symptoms you accurately described. Once over 90C the fuel is atomising properly, instead of partially condensing on the back of the valve head and the idle will smooth out. One way around this is to increase the cold start temp compensation on the PFC at the 70C bracket and increase it gradually until the idle smooths out during this transition period. Or , as you;ve found, leave the O2 F/B turned off but if you do you had better make sure your tuner did a good job of the light throttles or expect fuel economy to go out the window Hope this helps MIke

well I've spent hours tuning my own car and it had taken a long time and thats with using a wide band O2 and datalogging with datalogit software. Me, I'm just learning though and being very careful at the same time I must say, though, that I've made many improvements to the way me engine runs and got a real "feel" for what my set up likes and doesn't like. As every car is different this is where the experience that good tuners have can make the job a bit shorter especially if their familar with both the engine type and the computor controlling it. I can say, from my own experience , R32 GTR, that the PFC base maps are miles out! The lean cruise runs around 13.5: 1 instead of 15:1 between 1600rpm and 3200rpm load zone 3 to 6, it is also way lean when coming onto boost like 14:1 instead of 13.5 to 13:1 , and as soon as it hits boost load zone 13 and up it so rich that it blows black smoke out the back and by 4500rpm its heading towards 10.5:1 ! And thats just fuel Ignition timing is also miles out (retarded) esp at the bottom end between 1200rpm and 2000rpm @ light throttles. This could explain your flat spot. Up the top it way to advanced causing detonation at around 4800/5200rpm on 96 octane. I had to pull out 8 degrees at this point Load 14 /15/16 to stop it.... This is just what I've learnt from basic experimentation... I have had it on a dyno too just to check I was heading in the right direction and I was So far I have 200rwkw at 7200rpm at 14 psi and a very economical car at the same time lean cruise 15:1 at 100km in 5th . Mike

:bp: I'm working on a R32 GTR map with Datalogit at the moment ......its a lot of work but am making progress. I can post what I've done so far if you like as an excel 3d map? :jawa: Mike

try www.fc-datalogit.co.nz They do a comms interface and full windows software. Well worth the $$ for the results you can achieve. I've been using it for 2 years now and its worth every cent Mike

its all to do with the turbo outlet temps and the turboes efficiency at different boost levels nothing really to do with the intercooler unless of course you push the turbo boost to high and out of its efficiency range.

I'd say he means camshaft degrees, SK. good result though, dyno tuning is well worth it eh? I have the same cams in my R32 GTR but with high flowed original Turboes. I've been playing around on the dyno and got 185rwkw at 6200rpm, stopped there as it was way too rich , like 11:1 and we run out of time. We did however, get the boost controller sorted out which gave me a 20% increase in rwkw at 3800rpm which was well worth on the road! Well done. Mike in NZ

hi there, I brought, built and use the techedge meter. Its very good, very accurate (compared to the high speed AFR on a dyno dynamics dyno (in fact it uses exactly the same bosch sensor)) and I run it into my PFC datalogit program. Its awesome and allows on road tuning and full datalogging of all your runs When used with the datalogit program of course. I would highly recommend it MIke

I agree with all of the above! 370rwkw on 2510's with pump gas is a joke. etc etc etc etc also 25psi with these turboes is also a joke esp with a std internal engine ......apart from that, don't get obcessed with a hp number like so many people do. with that package you will have a very quick street GTR! just let it go...........

taped up coils..... lol I wonder how long that will last for Good on ya KIWI ingenuity! last time I had a punchure I tried chewing gum on the hole, lasted for a wee while...hubba bubba i think was the brand

www.fc-datalogit.co.nz I brought a copy...its very good and well worth it! together with a wand band you can tune to your hearts content all by yourself. Save heaps in Dyno charges and the like ....