R33 Just Wont Run Right, Need Constructive Help

[Pete K]

Hi All, Im having some issues with my r33 and after days of reading im just a little stumped.
I bought the s2 R33 nearly a year ago and have been working slowly toward making it reliable as a daily driver and a weekend track car. Im Just not making the power i was expecting, I have a good tuner who has worked on many hi horsepower machines and is willing to do what ever i want but im on a budget and cant just shell out money willy nilly trying to find an issue.
The first time we tuned the car it had a fmic and powerspirit turbo and a powerfc ( these came with the car ) i have no details on the turbo other then it looks cheap but appears to work not to bad under moderate driving conditions, unfortunately our tuning was cut short as the car started to run lean over 6000rpm and about 260hp as it could not supply the fuel required, the car had 225000k’s on it so i assumed it may be the fuel pump and decided as im chasing 320-350wrhp id bite the bullet and do a few upgrades before we tuned again.

So i replaced the front mount as i found 2 small splits in it, and also replaced all intake silicone hoses and hose clamps, then i replaced the fuel pump with a genuine walbro 255 high flow pump, tubosmart manual boost Tap, nismo 555cc injectors, apexi pod filter, z32 AFM, blitz nur spec exhaust, new bellmouth dump and front pipe and a catco hi flow cat from just jap.

I then took it to be retuned again, this time no lean issues at all and turbo seemed to spool nice and quick, but we started having issues as the horsepower climbed during the tune, we managed to get 296rwhp 6400rpm with 16psi. I feel this is a little low but im not to crazy on the numbers as long as its safe. But the biggest concern we had was the power began to oscillate quite violently once we reach full power, this could be seen and felt, we noticed as we turned the boost down the oscillation smoothed out. We ended up leaving with 279hp@14psi.
I left the dyno and the car was magic, but once on the highway everytime the car hit full boost it started to flash the check engine light due to detonation we were reaching about 60-80 knock.- I went back the next day and we tried to retune again this time with a slow ramp rate to try and simulate normal road loading, my mechanic wasn’t happy he said as the car is going to be track driven he really doesn’t want to see anything over 10 or 12 knock. We pulled some timing and played with fueling and I left that day with 254hp @5000rpm and 15ps @11.9afr

The car was defiantly down on power compared to the first time but the power was so smooth the car felt like it was NA, no big spike just very smooth predictable horsepower from 2500rpm( perfect for the track ) just low on power. The car ran fine for a few days no knock at all but one day i put the AC on and had 3 people in the car and the check engine light flashed again, and i have since found that any time the car is loaded it up be it a steep hill or full of people with the ac on when at WOT and have full boost this happens again, the knock light is set to a 30 count and i measure any where from 36-50. I have drained the fuel a few times now and have noticed best results from bp premium

We just cant seem to pin point what the issue is, 254hp @15psi is not to good, but the turbo appears to be performing perfect and its making 15psi with out any hesitation, for this reason i don’t just want to replace it, although i don’t know what its specs are , the fins look great and there is no shaft play.

The motor uses no oil at all during services every 3000ks, it blows no smoke other then the little puff of black smoke momentarily when a WOT, the car doesn’t get hot at all or use water, and their is no evidence of water in the oil to suggest a head gasket is gone. I recently installed a catch can from the 2 rocker breathers and recirculated it to the intake and after 2000ks of reasonably hard driving it has no residue in it at all.

Hope fully i have checked / done all the obvious things and im hoping some of the knowledgeable people on here can shed some light as to what the problem may be,
Ive just bought a compression tester and leakdown tester that ill get late this week, im not to confident it will tell me to much, as there are no other symptoms i can associate with worn valves or rings,

thanks in advance for you help guys
Cheer Pete

[Ben C34]

It's a shit turbo. What do you want to hear?

[WMDC35]

What other boost control other than the boost tee?

[Pete K]

What other boost control other than the boost tee?

7 psi actuator is all there is, factory control was removed before i bought the car

cheers

[Pete K]

It's a shit turbo. What do you want to hear?

very constructive, what makes you think its shit?

[Ben C34]

very constructive, what makes you think its shit?

I

What makes you think it's not?

Making 15psi isn't a way of judging it. Stock turbos will do that.

It's a shonky knockoff. You are wasting your time with it

[WMDC35]

Does it have a bit of boost creep? Could be why it's worse loaded up hill etc, maybe the wastegate needs a bit of porting or a better actuator like a turbosmart iwg75, always best to tune on the gas you're usually going to run

[Pete K]

I

What makes you think it's not?

Making 15psi isn't a way of judging it. Stock turbos will do that.

It's a shonky knockoff. You are wasting your time with it

I know its a cheap copy and there is a real good chance its the issue,but if it spools fast to 15psi and sits there to red line, shouldnt a healthy motor produce more power then what i am making? I have checked the intake plumbling and it appears to remain cool, so i dont think intake charge is overy hot, Im prepared to spend $1500 to replace the turbo but i can afford to replace the turbo only to find it has nothing to do with my issues,

cheers

[Ben C34]

A stock turbo can make 15psi. It will make a shit load less than a decent turbo at 15psi

[Pete K]

Does it have a bit of boost creep? Could be why it's worse loaded up hill etc, maybe the wastegate needs a bit of porting or a better actuator like a turbosmart iwg75, always best to tune on the gas you're usually going to run

it used to have issues with the actuator, it was poorly aligned and used to fully open and then could not close, but we have spent a fair bit of time getting it to function properly. i dont think it creeps , the boost tap appear to work as it should, it over shoots by 2psi then drops back and holds steady all the way to red line. if it was boost creeping would it slowly just keep increasing psi?

[Pete K]

A stock turbo can make 15psi. It will make a shit load less than a decent turbo at 15psi

Ohh really? I would of thought that given the same air pressure and density would mean the same volume of air each time it fires and so reguardless what type of turbos pushing the air it would make the same hp, But i admit im very green in the turbo world, and im usually wrong

[Ben C34]

Yep. In this case you are wrong.

Seems odd at first. Maybe look ar the rb25 dyno results thread and see.

[Pete K]

Yep. In this case you are wrong.

Seems odd at first. Maybe look ar the rb25 dyno results thread and see.

Will do cheers

[WMDC35]

Can creep/spike quickly so leans out & dets causing the knock & will do it worse with load in higher gears & uphill etc, hard to judge whether the power is low for the boost etc as don't really know the turbo specs

With different turbos just think a better or bigger turbo will push a lot more volume of air at the same pressure

[Pete K]

Can creep/spike quickly so leans out & dets causing the knock & will do it worse with load in higher gears & uphill etc, hard to judge whether the power is low for the boost etc as don't really know the turbo specs

With different turbos just think a better or bigger turbo will push a lot more volume of air at the same pressure

looks like i have a lot to learn about the way a turbo functions, i keep thinkings of turbos like a conventional compressor ie as long as supply of air is = > then the air required to drive the tool, the tool usually will perform as intended. what should i do? should i send the turbo away to be tested, buy a stock turbo for a small amount of money so i can ensure its not the motor or just bite the bullet and buy a new turbo?

[Kinks]

Turbos have a happy efficiency range. If you try and push a stock (or shit) turbo above its limits, the shaft speed will get really high and it will generate a lot more heat trying to build boost. a bigger, more efficient turbo will do the same boost level with less heat and lower shaft speed. heat creates detonation, and a small turbo creates backpressure which also makes the engine breathe poorly.

engines are essentially air pumps. the easier you can get air in and out, the more power you make. easier means less restriction. bigger pipes, bigger turbos, etc. boost is actually just a measure of restriction, it means to make the power you are having to try "X" hard to cram in the air. a bigger turbo will make same power at less boost. it just has more lag at the bottom end. you need to pick a turbo that's not too laggy but flows well at the power level you want.

you could have a stock turbo last fine at 20psi if your exhaust was a pea shooter like you'd find on a 1.3L hatchback. but would it make any power? no. because you have no flow

[Badgaz]

If you load the motor up you will hit areas of the map that might not have been tuned on the dyno for...... Which would be weird seeing as that is the usually why you would use a dyno, unless the dyno used didn't have a brake. Detonation is either too much cylinder pressure or too much heat remaining in the cylinders(small turbine cant evac heat fast enough)

[Ben C34]

Look at hypergear turbos. Excellent performance and value for money.

And Australian support.

Sorry if I came across harsh but as soon as you ditch that turbo you will kick yourself you didn't do it sooner.

[Pete K]

Turbos have a happy efficiency range. If you try and push a stock (or shit) turbo above its limits, the shaft speed will get really high and it will generate a lot more heat trying to build boost. a bigger, more efficient turbo will do the same boost level with less heat and lower shaft speed. heat creates detonation, and a small turbo creates backpressure which also makes the engine breathe poorly.

Thanks for that,

as the car will be used for track work... would it be possible to achieve 320-350hp below 6500rpm? im just a little concerned about extended high revving as my mechanic has a few rbs in the workshop that have lost the oil pump from prolonged high rpm, I would love to short shift a little if i can get away with it. Cheers

[Pete K]

Look at hypergear turbos. Excellent performance and value for money.

And Australian support.

Sorry if I came across harsh but as soon as you ditch that turbo you will kick yourself you didn't do it sooner.

No thats fine mate thanks for your honesty, i just didnt want to be guessing, as you can tell im very green