Why Is My Skyline So Slow

[scathing]

Whats your mates knowledge of the subject? Fairly detailed? or just a bloke that sat in the passenger seat for 5 minutes?

If he thinks a lack of backpressure in an exhaust is a problem rather than a good thing, then his knowledge is minimal.

The N/A supra is the king of the fast N/A 6's if your not too worried about the $$$, although if its about doing it cheaply a cammed and chipped Buick or Ecotec commodore will still cream a Magna.

TVR Tuscan / Sagaris will shit all over a NA Supra, and is technically P plate legal since they're not on the list, and don't have FI/8+ cylniders. A V35 350GT should run mid 14s quarters even with an average driver.

If we're not talking P plate legal (since you were quick to point out the OP never mentioned it) and we're "not too worried about the $$$", you can feel free to throw in:

350Z / 370Z

M3

NSX

Porsche 911 (of which the GT3 would be the "king of the NA 6's")

Lotus Evora

All of which will easily clean up a NA Supra, stock for stock or with similar bolt-ons.

[central coast person]

There is no such thing as a 4 door GTR, there is a company in japan that can make it for you but thats it.

Anyway too the GTS-4 .... It seems really slow for a GTS-4, mine will hit 100km/h in about 7-9 sec depending how i do and what the temperature is like etc.

Its pretty much stock except for carbon fiber hood, Kyb shocks that are 9kg front and 7kg rear, 17inch rims on falken 452's, 2.7L RB (whole engine rebuilt) and a pod filter (prooperly enclosed) all finished off with a tune.

i get a very sudden churp of my tyres front 1st-2nd and 2nd-3rd but its very quick and im using Falken 452's which are a very good and expensive tyre.

Go to the drags to see if you are still getting the same times but expect about 14.5-15seconds on the quater mile

[SKiT_R31]

There is no such thing as a 4 door GTR, there is a company in japan that can make it for you but thats it.

I was referring to the Autech GTR

http://www.infinitig35.net/R33/4door/

[mad082]

Back on topic, I have an R33 GTS4, used to be N/A and it would happily do a 0-100 in <8seconds without a hard launch. They weigh around 1440kg, about 100kg lighter than a VT, but the difference is VT's have a lot more power in the lower rev range, due to their higher capacity, whereas an RB25DE only really has good power between 4500-6500rpm. HOWEVER, this is countered by the ridiculously short gearing of the GTS4, 50kmph in first and 85kmph in second, made it quite snappy when N/A.

My car had a 2.5" exhaust, enclosed pod filter, "highflow" cat, and about 25 degree's ignition timing at idle, it had 110kW at all fours, which is nothing special, but its not bad, its about what an Ecotec gets with the same mods (exhaust and intake) - that's the engine in the VT BTW.

So to fix the OP's problem, i would firt say, exhaust, is it stock? If so, change it, its old and knackered, and some more flow will benefit the choking N/A. Secondly, the Cat, its most likely blocked, i would either decat it, gut it or replace it with a high flow. and finally, ignition timing - wind it up, if its an older import, it may have been wound back to run on 91 octane, it could have been put at the wrong spot after a timing belt change, anything. I would say 20degree's minimum, and keep winding it up until it either stops making power or pings, i wouldn't recommend more than 30.

I'm assuming your on your P's, since otherwise you wouldn't want an N/A, so just conceal your mods, make them tidy and quiet!

I bought my GTS4 because i wanted a 4 Door AWD car, and couldn't find a 4 door R33 GTR (they do exist, but pricey and rare) It now has a FMIC, 8psi on an R34 turbo, 15degree's ignition timing, GTR gearbox (for the taller gearing), billet lightweight GTR flywheel and HD clutch, and is incredibly responsive, plenty of power for a daily, the motors cope with boost well, its comparable to another car i have in my driveway (same 1/4 mile, but slower to 100), R33 GTST coupe, FMIC, 3", SAFC & 12psi. but the GTS4+T is a lot more responsive and zippy (and therefore fun), due to having traction for hard launches (and hard power hit), and the much shorter gearing.

also the gearing in commodores is much taller than any skyline. generally about 35% taller. that is a manual commodore compared to a GTS-t. compare it to a gts4 it would nearly be twice as tall. that is the thing with the commodores and falcons. they will go as fast, or faster than a skyline (top speed wise) in most gears and yet they will be reving around 2000rpm less. so in the case of the gts4, taking off in second gear would be the same as taking off in first gear in the commodore. that kind of puts their performance into perspective. shortening up the diff ratio but 10 or 20% can make a massive difference to how fast a commodore is.

[mad082]

I was referring to the Autech GTR

http://www.infinitig35.net/R33/4door/

again, that isn't a genuine nissan product. that is an aftermarket built car. sort of a bit like the RUF porsches. they take a new car and change it/tune it. they aren't actually built that way by nissan.

[Messiah]

If he thinks a lack of backpressure in an exhaust is a problem rather than a good thing, then his knowledge is minimal.

He's right, a lack of backpressure on an NA exhaust IS a problem. NA's use exhaust tuning to help with the scavenging of gasses from the engine and rely on a certain ammount of back pressure to perform. Too big an exhaust on an NA car can ruin this affect.

FI cars do not have this problem (other than tt supras where a high flowing exhaust can cause fgasses to bypass the waste gate).

[central coast person]

I was referring to the Autech GTR

http://www.infinitig35.net/R33/4door/

yeah thats the company i was talking about, they will do it if you pay them.

Its cool, if you ever get one make sure i see it

[FrangaR33]

If he thinks a lack of backpressure in an exhaust is a problem rather than a good thing, then his knowledge is minimal.

TVR Tuscan / Sagaris will shit all over a NA Supra, and is technically P plate legal since they're not on the list, and don't have FI/8+ cylniders. A V35 350GT should run mid 14s quarters even with an average driver.

If we're not talking P plate legal (since you were quick to point out the OP never mentioned it) and we're "not too worried about the ${:content:}quot;, you can feel free to throw in:

350Z / 370Z

M3

NSX

Porsche 911 (of which the GT3 would be the "king of the NA 6's")

Lotus Evora

All of which will easily clean up a NA Supra, stock for stock or with similar bolt-ons.

350Z vs NA supra would probably be quite close I reckon. As far as the rest go theres not caring too much about the money and then theres 60k + for a car which most of those are. Not knocking the cars though all brilliant NA's especially the NSX, by the way the current M3 is a 4.0L V8 although if were talking the E46 that has the most brilliant 3.2L inline 6 ever so much power from such a small NA engine that will still today give even a new M3 a run for its money 0-100.

[SKiT_R31]

He's right, a lack of backpressure on an NA exhaust IS a problem. NA's use exhaust tuning to help with the scavenging of gasses from the engine and rely on a certain ammount of back pressure to perform. Too big an exhaust on an NA car can ruin this affect.

FI cars do not have this problem (other than tt supras where a high flowing exhaust can cause fgasses to bypass the waste gate).

While this may be true with older vehicles, it is not the case with almost any new vehicle, including N/A skylines. Regardless, the less resistance against the piston on its exhaust stroke, the better. Putting an exhaust on a car that is too large, is bad for both N/A AND turbo cars, and its not due to "not enough back pressure" its due to MORE back pressure, from having to push a larger volume of exhaust gas out, at a slow rate (giving it time to cool and become denser, therefore creating even more back pressure). Regardless of the car, you need the correct size piping, and the less restriction the better (i.e. higher flowing mufflers, cats). Long gone are the days when you needed back pressure to stop pissing air/fuel out of your exhaust due to cam overlap etc.

again, that isn't a genuine nissan product.

lol, i never said it was, all i said is that i wanted one, its still branded a GTR, therefore, its a GTR 4 door, which is all i wanted. I didnt say "An original nissan branded magic 4 door GTR".

But i don't think I'd get one anymore, my current 33 more than satisfies me, with power/delivery, handling etc, its just a daily so anywhere between 160-200kW ATW is fine IMO. With an SAFC2 & more boost tuned on the dyno, that's my goal range, although, i suspect I'm already at least in the lower half of that, its pretty spot on as it is, I'd would rather it be reliable and street able and sink the $$ and time into my track car.

Edited February 24, 2010 by SKiT_R31

[PM-R33]

350Z vs NA supra would probably be quite close I reckon.

Not a chance. 350Z would easily pull away from the surpa and the 370Z even more so.

[FrangaR33]

Not a chance. 350Z would easily pull away from the surpa and the 370Z even more so.

Would depend on Launches, Auto vs Manual etc.

0-100 350z 6.1 seconds, NA Supra 6.5

Could be reasonably close I reckon. Manufacturer figures arent always spot on as shown by fifth gear. I've seen a NA supra crush a mates R33 GTST and a F6 so I reckon its a possibility.

[mad082]

Would depend on Launches, Auto vs Manual etc.

0-100 350z 6.1 seconds, NA Supra 6.5

Could be reasonably close I reckon. Manufacturer figures arent always spot on as shown by fifth gear. I've seen a NA supra crush a mates R33 GTST and a F6 so I reckon its a possibility.

yeah but what mods were done to the supra and what mods to the f6 and the gts-t? sure a supra that has had 10k of headwork done will beat a stock supra, but in stock form against a mildly modded 33 the supra should lose, unless the 33 driver is a stooge or has super stiff coil overs and crappy tyres and loses simply from lack of traction.

[Super Drager]

Would depend on Launches, Auto vs Manual etc.

0-100 350z 6.1 seconds, NA Supra 6.5

Could be reasonably close I reckon. Manufacturer figures arent always spot on as shown by fifth gear. I've seen a NA supra crush a mates R33 GTST and a F6 so I reckon its a possibility.

Simple answers to that, The R33 GTSt and F6 drivers couldn't drive for shit . My 300ZX has beaten several NA supra's by quite a bit and in all honesty there is no chance of either of them beating an FPV, he was most likely humouring the supra and the r33 gtst couldnt drive for shit.

[DivHunter]

This thread in this section of the forums tickles my schadenfreude in ways you can never imagine.

Carry on.

[adis]

n/a 33 with 123 rwkw can do 14.5.. duno whats up with your car.

also i think i need some evidence to help give the n/a skylines some self respect back:

could be:

1. P platers that dont know how to drive.

2. P platers that root there car and dont service / take care of it.

And yes im a p plater not dissing them at all.

I dont know but maybe i live in a different world.

Took the car down to Heathcote, 32c.

cAR R33 TURBO, hiflow, mines ecu, 15 psi/ 225kw at wheels. 14.0s flat.

And here people claim they make 120kw and do 13-14s?? errr, okay

[Tony de Wonderful]

Took the car down to Heathcote, 32c.

cAR R33 TURBO, hiflow, mines ecu, 15 psi/ 225kw at wheels. 14.0s flat.

Hot day? Sound a bit slow for that power.

[UNR33L]

Not trying to start a shit storm here.. but maybe its the driving?

Looking at drag times around the forums (vic section etc) mildly modded gtsts get 13.6 ish easy

[Super Drager]

Not trying to start a shit storm here.. but maybe its the driving?

Looking at drag times around the forums (vic section etc) mildly modded gtsts get 13.6 ish easy

Thats the thing, it IS the driving. Shit driving = shit times no question about it, people need to see that they need to improve their driving skills and not bitch and moan about a car with 100kw less almost matching their times.

[MBS206]

I dont know but maybe i live in a different world.

Took the car down to Heathcote, 32c.

cAR R33 TURBO, hiflow, mines ecu, 15 psi/ 225kw at wheels. 14.0s flat.

And here people claim they make 120kw and do 13-14s?? errr, okay

For your claimed power, you should be running mid/high 12s...

190 - 200RWKW is seeing consistent 12.9s from people.

[Crackfox]

While this may be true with older vehicles, it is not the case with almost any new vehicle, including N/A skylines. Regardless, the less resistance against the piston on its exhaust stroke, the better. Putting an exhaust on a car that is too large, is bad for both N/A AND turbo cars, and its not due to "not enough back pressure" its due to MORE back pressure, from having to push a larger volume of exhaust gas out, at a slow rate (giving it time to cool and become denser, therefore creating even more back pressure). Regardless of the car, you need the correct size piping, and the less restriction the better (i.e. higher flowing mufflers, cats). Long gone are the days when you needed back pressure to stop pissing air/fuel out of your exhaust due to cam overlap etc.

I know hardly anything more complex than changing my oil but I got a 52% in year 10 physics and I dont understand this. The volume of exhaust gas would be inversely proportional to pressure so you are saying that a larger exhaust volume=lower pressure in exhaust system=???=more backpressure. And lets say in the 30 minutes it takes for the exhaust gases to pass through the giant exhaust they cool down. Lower temperature means the molecules in the exhaust fumes are moving at a lower speed thus providing a lower pressure for the same concentration of particles and this somehow increases backpressure as well?

OP: Car is slow because its a 1.5tonne 4wd being powered by a 15 year old naturally aspirated 2.5L engine

Edited February 24, 2010 by Crackfox