FATGTS-R

I have a/m ecu and I guess the cold start mode needs some work because as someone else mentioned it will stall if I drive it stone cold. To get out of my estate there is a million roundabouts and it will stall when the revs drop halfway around one, which was very interesting the first time it happened. Basically, in cold start mode it idles at about 750rpm but if I blip the throttle it will go up and then come down to zero and stall. As it warms up it doesnt go down past the idle rpm as much untill its ready and dont go down past it at all. I have read previously about the possible ill effects of prolounged idling so my procedure is to sit in the car for approx. 3-5 minutes ( cold morning only ) with it running but instead of letting it idle at a constant rpm I constantly mix between blipping the throttle and holding it at different rpms before driving off and waiting for oil pressure to drop.

Find out with the EMS dealers if there unit can support high and low impedance injectors without needing to change any software/hardware. I had GTR injectors ( low impedance ) with an aftermarket ecu and recently changed to high impedance injectors and the ecu needed the injector drivers changed to suit.

From the way you are describing it, it would of been blowing this smoke when you test drove the car? If so, why did you buy it? Also, why did you not get the car thouroughly checked out before buying it?

You have a red top version RB20 with a 6 port head? From what I knew no such thing exists, only the silver top RB20s had a 6 port head with both red top versions having a 12 port head?

From memory, R31nismoids GT30 equipped RB25 sees about 16psi at about 4,000rpm with a tuned length exhaust manifold and all support systems. The RB25 is 25% larger in capacity than the RB20 so in theory it would see 16psi 25% later in the rev range at approximately 5,000rpm. So I guess, if funds allowed and you wanted to take that route a GT30 might be a decent match for a no holds barred 9,000rpm RB20.

How much work can you do yourself? If its little, take others advice and get a car with a headstart on the mods i.e exhaust,cooler, fuel system and PFC. At present, my opinion is its a buyers market for skylines and there are some decent cars with above mods going for reasonable money. Because $10K gets gobbled up frightingly fast if you pay retail workshop labour rates.

How would a turbo from a VL perform on an RB20? I ask as I have a GTSR with the standard fitment T03/TO4e which I think would be similar in specs to a standard VL turbo. Yes, the technology is from the dark ages but I gather they are also cheap to pick up for the budget concious (sp). I currently have 235+ rwkw with all support systems at 16psi which is reached at about 3900rpm.

Will be watching this with interest as mine just started doing the exact same thing last night in the exact rev range as well. Sounds terrible, from in the ****pit I thought it was the gearbox from all the vibration reverberating through everything. On the plus side, if the timing cover and associated gear has to come off I will throw some vernier gears in there.

In my opinion I reckon its a little late if you are still using the standard RB20 turbo. Even in dead standard condition Im sure it should be seeing 13 psi before 4,000rpm. I have a T3/TO4e on an RB20 and 16 psi is seen at 4,000rpm.

Nice result indeed. Can I ask if boost pressure remained the same from before and after the new housing?

"the obvios answer tho is if you want to make over 200rwkw its alot safer to upgrade your injectors etc" If thats the obvious answer then the answer to your thread is obvious. As I mentioned I made 187rwkw and I got a call from the tuner ( I said I would be happy with 200rwkw) telling me I could have my 200rwkw if I wanted an a/f ratio in the 13s but he wasnt going to take it there. After a long drawn out slog which I wont get into in this thread I got my car back today with 235rwkw (rb20) using 510cc injectors,standard reg and a GTR pump.

As I mentioned earlier my 1987 skyline came factory without a BOV. I fitted one originally solely for the purpose of drivability. I actually came onto this forum the first time asking why it was stalling after a boost event and then clutching it and rolling to a stop. I was told it was because I had an atmo venting BOV or none fitted at all. I honestly didnt beleive it at first as I didnt think a dead standard factory vehicle would behave in such a way. But I fitted a $40 bosch unit and the problem disappeared. I can understand the argument about emissions and crankcase gasses from the rocker breathers being vented to atmo through the air filter but maybe there was a drivability issue as well? If I had bought the car from new and it was stalling like that I would of immediately taken it back thinking something was wrong. On a side note which is supercharger related, not turbo, but related to BOVs, my best mate has a centrifigul Vortech supercharger which originally failed after less than 1,000kms and a replacement failed again after a few hundred ks. The supplier ( CAPA ) claimed the problem was not with there units but that there was "not enough release cfm from the inlet tract when the throttle closed causing undue stress on the reciprocating components". The third unit was installed along with two big cfm venting BOVs and has ran without dramas for nearly 10,000ks and counting.

Not that it means anything but what does the odometer read? The other thing I would be concerned with is not what they found but what they didnt find. Did they perform a compression or leak down test? How much does the seller want for the car?

Well using the injector flow formula which I learned from this forum: 270cc / 5 = 54bhp x 6 cylinders = 324bhp which equates to around ~195kw at the wheels. In my situation the formula held up as I reached 187rwkw and needed to upgrade them. For 250rwkw the 440cc GTR injectors would do the job and not cost the earth at $250-$300.

I dont think the theory is that it will break the compressor wheels or bend them its more to do with them spinning in one direction and the air coming back against it placing stress ( how much who knows? ) on the complete rotating assembly, bearings etc. I also have an import R31 which came with no BOV at all but I fitted a Bosch unit because in theory I beleive having none at all cant be good. I need to upgrade it now as I have increased boost pressure, hence airflow to the point where it cant vent it all and I get a small amount of flutter as some of it goes past the bov and through the turbo.

Hi Shaun, I have an Autronic SMC (RB20) and just thought I would throw in my 2 cents. To be blunt its been a nightmare. The car has been back to the shop ( its there now ) so many times I cant count. But this could be tuner related and also I have changed a few things along with the fact the car is from 1987 so take it with a grain of salt and not an attack on the product as research will show it has a great track record. In saying that one unit was found to be faulty after a month or so which cost the workshop considerable money and labour chasing a gremlin that was a dud unit which cost him three weeks of labour and wages, 300 litres of fuel and over 40 sets of plugs. I guess I'm biased now because of my troubles but if I could have the decision again I would have chosen a PFC. I got a great price on the unit and install but got caught up in the hype of having an Autronic ecu thinking nothing can go wrong but didnt ever think about all the little things that end up as being big things i.e cold start, hot start, electrical load compensation etc which as SK mentioned can take days which end up as weeks and months if if you want a great result. As an example my cold start alone was a fortnight before the tuner was happy to give the car back to me but I must say its like factory now. I guess what Im trying to say is that the Autronic although being a high end ecu requires patience to get right and make the most out of it whereas the PFC although not having all the functions has a great head start being model specific and having a lot of things pre loaded into it like the cold start etc. You never realise how great a cold start mode is untill you have to crank for 10 seconds to fire up and then sit there for ten minutes blipping the throttle before you can drive off without stalling. Just need to remember that the factory ecu programming would of had an army of technicians with a mega budget and years to get right. Dont think XYZ workshop can come even close to emulating this in a few hours on a dyno. Sorry to rant but good luck on whatever decision you make. Jayson.

What turbos were fitted to the engine before the crash?

Interesting stuff. I also have an Autronic SMC ( RB20) and was running standard single pintle GTR injectors. These have now been swapped out for high imp bosch multi pintle injectors at same capacity and tuner noted he had a lot more precise control with them.

It might be $22 to fill the tank but it wont last as long as the tank of petrol. In relation to the gas injection, Gas research have a throttle body which has been around a long while that has injectors plumbed into it. My friend went with it but tuning was a nightmare so it got the toss. Electronically controlled gas injectors with one per cylinder are a recently new thing but they are still having trouble with them freezing from what I have been told. A guy on the R31 forums got quoted from memory $4-5k to fit the electronic gas squirters to his RB20det and they were goiing to plumb them into the inlet manifold runners but the said they could only guarantee the quoted fuel flow 80% of the time I assume because of the freezing issue.

You have mentioned catch can and oil in the pipes so I assume its set up legally and the can is running as an oil/air seperator? Clean up all the inlet pipes and run the breathers to the can but dont plumb them back into the inlet, vent it to atmosphere. Then take the car out for a spirited drive or two and then check the afm pipe. If it is filthy with oil again then obviously the turbo is sick. If its clean and the can is full then get a leak down test performed.

ratios are also different i beleive.

Mine regulary gets called a " c@nt of a thing" or a "piece of sh@t".

I have had this problem many times and had many reasons for it. As mentioned it could be a faulty plug or a faulty ignition coil or module. It can also be caused by a leak in the inlet tract. As you heard a hissing sound around the throttle area I would be starting there first and looking closely at the rubber joiner for a split. And while you have the crossover pipe off may as well throw in some new plugs.

"FATGTS-R : Thats still quite good ! what turbo are you running?" It is the R31 GTSR factory turbo which is basically a T3 ex housing and a T04 compressor cover and wheels. It also has the factory tubular long runner ex manifold which helps a bit too I guess.

OK I was a bit ambitious to post what I said earlier without seeing the graphs as I assumed boost level was same as before. Actual boost level this time is a more beleivable 16psi (4,000rpm) but still a result I am happy with considering its the factory turbo. But.....I didnt even make it home. As alluded to earlier I have had many a drama with the ecu having a mind of its own. Its already been swapped for an exchange unit, been nearly completely rewired and given the poor sod whos task its been to get it right nightmares. The workshop kept it a few days after they thought it was right to see if anything reared its head and were positive it was working as it should. Before I left, I drove it around the workshops area for 30 minutes and was very happy and gave him the thumbs up. 15kms down the road and its sounding like a WRX again and down on power. Turned round to limp it back and not even a km later it loses another 40% power and stalls and then wont fire up at all. So back to the shop again. I swear modifying cars is for the insane.