Jump to content
SAU Community

Recommended Posts

Hay guys, had my gtr tuned a while back and it was lacking on power something fierce.... it running 350 hp at all four on 15psi.... it built and all the rest... ive changed the exhaust twice and seem to not change anything.... the only thing i can think is the exhaust is very quiet for a 3.5 inch hks..... it got a high flow cat. but i cant seem to find the problem.....maybe the turbo???? maybe the manifold?? maybe the exhorst????

any ideas would be great....

thanks

ps would like it to spool bout 1000rpm earlier, any ideas also would be great....

oh yeah the turbo comes on about 5200 rpm full boost... i think thats a little late but not to sure.....

Link to comment
https://www.sau.com.au/forums/topic/317522-lack-of-power/
Share on other sites

  • Replies 49
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Posted Images

Ok first thing you gotta ask yourself, does it make much more power on much more boost. If the answer is no, you know you have a problem.

You said you changed the exhaust twice, as in the catback? That usually aint going to do shit as the exhaust restriction is usually due to a collapsing cat. What "high flow" cat is in there?

What does the power graph look like? What are the turbo specs? What ECU?

Also if it was tuned a while ago and made that power on 15psi, what did the tuner say? Why did he leave it like that and give it back to you.

Need more info man.

Edited by PM-R33
Link to comment
https://www.sau.com.au/forums/topic/317522-lack-of-power/#findComment-5190864
Share on other sites

sorry guys. its got- stock cams. garret t04z .70 and .84. jap manifold. tial copy 44 mm gate. 3 inch dump. 3.5 inch magna flow cat brand new. 3.5 inch Hks exhaust. 044 pump in tank. 780cc injectors . vipec comp. tuned by godzilla motor sport. made 280Hp on 11psi. 350Hp on 15psi. 380Hp on 17 psi. my exhaust is really quiet. my mate has same exhaust and can't even tell my car is on when he is sitting next 2 me at the lights. we tried swaping exhaust and taking cat Out no difference yet. but haven't checked on dyno.

Link to comment
https://www.sau.com.au/forums/topic/317522-lack-of-power/#findComment-5191181
Share on other sites

A feller I know recently was playing with an RB26 in a VL , it had a 6Boost manifold with a 44mm TiAL and a GT3582R with the 1.06 AR turbine housing + questionable 3" exhaust .

He felt he made significant gains by having a 3.5" exhaust all the way through , just about everything I've seen indicates that the exhaust needs to be BIG right behind the turbo and if I was you I'd strongly consider having a 3.5" if not larger dump pipe .

That feller mentioned above also found that the 44mm waste gate wasn't coping and boost crept upwards , had a different fitting welded on for a 50mm Turbosmart gate and that solved the creep problem .

From memory he had a 100 CEL cat fitted , don't remember which brand .

For the record does the turbo and manifold use a T3 or the larger T4 sized mounting flange ?

A .

Link to comment
https://www.sau.com.au/forums/topic/317522-lack-of-power/#findComment-5191275
Share on other sites

A feller I know recently was playing with an RB26 in a VL , it had a 6Boost manifold with a 44mm TiAL and a GT3582R with the 1.06 AR turbine housing + questionable 3" exhaust .

He felt he made significant gains by having a 3.5" exhaust all the way through , just about everything I've seen indicates that the exhaust needs to be BIG right behind the turbo and if I was you I'd strongly consider having a 3.5" if not larger dump pipe .

That feller mentioned above also found that the 44mm waste gate wasn't coping and boost crept upwards , had a different fitting welded on for a 50mm Turbosmart gate and that solved the creep problem .

From memory he had a 100 CEL cat fitted , don't remember which brand .

For the record does the turbo and manifold use a T3 or the larger T4 sized mounting flange ?

A .

+1 a 3" dump pipe behind a T04Z is criminal. 3.5" at an absolute minimum.

The other thing I would try is running it on the dyno without a cat, so just using the dump pipe.

Link to comment
https://www.sau.com.au/forums/topic/317522-lack-of-power/#findComment-5191454
Share on other sites

Power and response see about right for your combo, This GTR only made 369hp @ 15 psi and 461hp @ 17 psi the T04z is a cop on a std rb26 until 20-24psi (decnt manifolds do help a bit).

The same setup then made well over 500awhp @ 22psi. Your boost response seems about right too for your setup.

post-34927-1271809409_thumb.jpg

Link to comment
https://www.sau.com.au/forums/topic/317522-lack-of-power/#findComment-5191485
Share on other sites

Just for shits and giggles check out the gt2860-5 @15psi versus To4Z @15 psi, i wont post the -7's or -9's as it is even better again.

The T04z needs minimum 20psi to wake up and a redline of 9000rpm, not ideal for a stocker.

post-34927-1271809998_thumb.jpg

Link to comment
https://www.sau.com.au/forums/topic/317522-lack-of-power/#findComment-5191498
Share on other sites

Just for shits and giggles check out the gt2860-5 @15psi versus To4Z @15 psi, i wont post the -7's or -9's as it is even better again.

The T04z needs minimum 20psi to wake up and a redline of 9000rpm, not ideal for a stocker.

interesting... r32-gts t04z was making 520rwhp on 16psi and mine made over 500 on 17psi

both were also making loads more torque between 4000-5000rpm compared with the graph you posted... something wrong with the setup?

Link to comment
https://www.sau.com.au/forums/topic/317522-lack-of-power/#findComment-5192197
Share on other sites

well im seeming to agree with you guys about the dump, but have seen the same turbo come on harder alot earlier with the same set up. and make more power at 18psi...... there is a gtr at godzilla motorsport that runs the same turbo and has made 540hp on 18psi , the only differance is a set of cams, and a sub zero manifold, and a 4" dump + cat back.....

i am not running cam gears yet.. the are sitting in a box under my bed atm...... as cams would be good also - any sugestions????

the engine is rather fresh and godzilla motor sport didnt want to push it to hard......

as for response id like to drop it buy about 1000 to 1500 rpm...... so im thinking :cams : cam gears: 3.75" dump: sub zero manifold : hpc coating:

any thing else would be great......

ps i ran a set of standard turbos with same engine and it ran 330 kw on 19 psi..... and came on at 2500 rpm... would it be cheaper putting some steel wheels on these and boosting them up????

Link to comment
https://www.sau.com.au/forums/topic/317522-lack-of-power/#findComment-5192604
Share on other sites

Yeah, they said to put cam gears in it, change the exhorst ( remove the middle muffler ) change the intake pipe (pod set up) and maybe a cold air box...

out of that the exhaust has been change to a hks 3.75 inch, pod has been moved into the guard with a cold air box.....

the only thing im waiting for is cam gears to go on , i just dont want to put cam gears on it and them 6 months later put cams in... trying to figure what to get for it.,.....

sorry it was 330 hp.... was looking at the wrong sheet...

Link to comment
https://www.sau.com.au/forums/topic/317522-lack-of-power/#findComment-5192642
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • Nah, if I need to fit people in a car I'll just use the Mrs car, the MX5 is perfect for what I need as a fun little sports car for fun on the street As for getting in and out of the MX5, I have no issues as I am a short arse who does lots of mobility training 🥷 If anything, I have been looking at Daihatsu Hi-Jets for a work hack, I helped one of my mates move some stuff with one recently that he picked up from Just Jap, it was a little ripper and plenty big enough for what we needed, it would also be super handy for me as I do alot of gardening, and plan on having some veggie patches and native gardens in the place I buy next year when I retire I did alot landscape gardening and growing veggies prior to my current job, and loved it, and that is a hobby that can keep me sane in my retirement, and as such, the little 300kg load capacity would be more than enough for what I need it to move around I have been looking at utes for just this purpose for a while now, and a near new 2024 Hi-Jet can be had for under $30k And I would rather look at a quirky little Hi-Jet than pretty much any other little ute, well, apart from a Brumby, I love the little Brumby, and weirdly have never owned one yet I was going to buy a heap of raffle tickets to try and win the Brumby that MCM built for Subaru Australia, but sadly I totally missed the raffle, I even filled in some form to be told when the raffle started so I could buy tickets, but to my dismay I was never contacted and found out I missed it when I was randomly googling Brumbys last year... #conspiracy  Maybe I should just buy a Brumby for a little "work hack".....LOL I use to be indecisive, but now I'm not sure
    • Well.... it's not just "de-oxygenating". If you do that you just have, most likely, ethane. So you still need to do a synthesis step to combine a number of ethanes/ethanols to make circa-8-chain hydrocarbons. And of course you don't want straight chain HCs, because n-octane actually has a negative octane rating (ie, it's worse even than the n-heptane which sets the zero on the octane scale!), so you have to do some tricky catalytic chemistry to synthesise branched HCs. That's all doable - but it doesn't come for free. And.... it starts with ethanol, which is an agricultural product, and there will almost certainly never be enough of that as a base stock to replace the liquid fuels that are in use. You really wouldn't want to be planning to be using any more ethanol for fuels than is currently already used (in E10, E85s, etc). And ideally you'd be looking to reduce such usage, as it is largely wasteful, particularly in the stupid-ole'US-of-A where the corn lobby has organised it so that it's actually primary production corn that is used to make a lot of the ethanol, not by-products and waste, like it is (mostly) elsewhere. So, what I said about needing free-ish energy probably still applies. True synth fuels would be made from H2 and CO2, in a near reversal of the combustion process. In fact, given that the H2 would be split from water first, it actually is a complete reversal of the combustion process. But...energy intensive. The human race burns something like 1 cubic MILE of crude oil, after it has been made into various fuels. Every year. That's a simply stupendous amount of energy. Just assume that the density is 900 kg/m3, and that the calorific value is 45 MJ/kg, then that is 165.9 x10^12 MJ of energy. Or more than 10^19 Joules. You get a maximum of 1 kJ/s per square meter solar radiation falling on the planet's surface, and so if you halve that for daylight, and halve it again for average weather (highly optimistic) and then take ~25% for the very best efficiency of solar panels, then you need about 85.7 billion square metres of solar panels to generate enough electricity to replace that liquid fuel energy consumption. Each panel is about 1m2. That's a rather large number of panels. We also burn about a cubic mile of coal. We also use hydroelectric power. We also use nuclear. We also use a number of other sources, both "renewable" and not. You can kind of ignore the renewable ones (except for hydro, because it will all end up getting subsumed into pumped hydro for storing other renewables, and so it won't be the standalone renewable that it originally was), so we end up needing a multiple of the ground area number that I just arrived at.
    • Corvette thread then? Don't say I didn't predict the future again. "I love the little MX5, I do, but I just want something a little easier to get in/out of, a little more cushy and some power would be nice - I miss the V8 Rumble... I found this clean red C5 for sale recently and..." I'll do you a great deal on the next step, which is one of those but you can fit people in it, too.
    • What about renewable diesel and/or gasoline? I see some projects spinning up like de-oxygenating ethanol to make drop-in compatible bio-gasoline especially in CA. I still think the future is EVs and we should've all gone full throttle on nuclear power after the 1973 oil crisis like France. Despite 15 years of work in CA to reduce the CO2 intensity of generation with renewables our electric grid is still far worse than even "low carbon" nuclear power. ICE is pretty cool when you aren't depending on the stupid thing to be practical and reliable and cheap as possible to get you to work every day. It's kind of like mechanical watches or vacuum tube amps.
    • I just rolled over "my" first 10k km in the MX5 Every time I go anywhere it always ends up in a adventure to look at houses and find some random country roads I've been on leave since early November but unfortunately need to go back to work on 19 January Luckily though I still have a fair chunk of leave left to burn until.... Not that I'm counting 😁
×
×
  • Create New...