Traction, Restriction/hesitation And Inconsistent Power

[R32Abuser]

Ok... so having done a few k's with the new motor I have a few issues/observations which I want to know whether they are consistent with what others have noted.

For details of my build please see:

http://www.skylinesaustralia.com/forums/topic/376666-power-ceiling-gt3076r/page__hl__ceiling

AND

http://www.skylinesaustralia.com/forums/topic/371076-rb2530det/

FYI Motor is still on castor/mineral oil as I am doing 500-1000km before changing to synthetic.

My first issue/observation is the immediate lack of traction achievable in 1st/2nd/3rd gears

Now although this change is blatantly obvious due to the dramatic increase in torque from my previous motor (RB20DET), I'm wondering what you guys are experiencing...

This is all in the dry BTW:

1st gear is pretty much useless @ more than about 1/2 throttle...otherwise she spins up

2nd gear EASILY torches the tyres when full boost comes in (~3200RPM) and if you don't modulate the throttle to minimize wheel spin, it all just ends up in alot of smoke/noise through to cut-out (7000RPM)

3rd gear will just be able to hold the tyres in line with them spinning up "ever so slightly" until about 5k rpm where power/torque has nosed over (see above post links)

Suspension setup is the Sydney Kid GB. 235/45/17 Bridgestone RE001 rears with probably 60-70% left.

My idea to assist traction would be to go to a 255/40/17 and potentially go to a semi-slick such as a KU36. However, I just don't see these changes being able to make such a significant difference considering the torque. What setups are most members running and what are your observations? Do you guys find that having the additional torque from RB30 and a decent sized turbo that it is just not "practically" useful on the street?

Of course this is assuming we are not spinning the tyres every time we want to give it a squirt below 60-70km/h in 2nd or 3rd.....

Secondly, when ever the motor comes on boost at throttle positions between 75-100%, it almost feels as though something is "restricting" the car. What's moreover is the power that the motor delivers feels very inconsistent. I.e. non-significant changes in ambient temperature- one time the thing will feel like a ball tearer, the next time it will feel "flatter". By no means is it a lesser feeling than say an RB20/RB25 DET setup, but it just doesn't feel as consistent in putting out power as the OEM tune did. Have any of you forklift motor owners experienced said "feeling"? Could this potentially be related to a temperature compensation in the Nistune ECU reducing the timing the motor sees as the engine gets hotter from the previous "squirt"?

Thirdly, as soon as you change gears, the motor feels like the rev's drop SIGNIFICANTLY more than what I would normally expect during the time the clutch is depressed- it's as if the engine is wanting to stall! Now I believe this to be partly caused by some reversion coming from the turbo (NOTE: "chopping" sound after gear change occurs) playing funny buggers with the AFM readings. Intake side consists of stock BOV setup, 3" metal intake pipe (pissed off the OEM rubber item). Any of you care to share your thoughts on this issue?

All in all, I'm happy with the setup but have these few drivability issues to sort through to make this a more comfortable streeter.

Any thoughts/comments etc. are much appreciated

[Duncan]

The tyres and size should be OK on face value - how old are they?

What are your rear wheel alignment settings?

Do the wheels tramp (bounce) or spin evenly?

Is it 1 wheel spinning or both?

[The Bogan]

Pedal control is something that you need to learn, mine is the same with wanting to bag the wheels, progressive acceleration in relation to road speed, get these two areas right and you should be fine.

Even quality tyres will want to break away if you just mash the go pedal, with power come great responsibility, if you just look at the finger you will miss all the heavenly glory, LOL.

As Duncan said, whats running in the rear, if its single legging you will need to fix that ASAP.

It's like riding a big sports bike in the wet, ease it on, control the rear and its all good.

[Dobz]

What are your rear alignment settings as duncan said?

A lot of negative rear camber will make wheel spin easy.

[R32Abuser]

Tyres are within a year old so I wouldn't have thought that the compound had "gone hard" from sitting around doing nothing with no heat cycles.

Yeh, atm I am using the right foot to modulate the power feeding to those tyres but was just wondering if a lot of these observations are consistent with what others experience.

Alignment is as follows from when the rear tyres were installed:

FR

Caster = 6 deg

Toe = 3mm total toe out (1.5mm each side)

Camber = -1deg

RE

Toe = 0 mm total

Camber = -0.5 deg

My old 100% worn tyres used to axle tramp, until I got my current set of tyres installed and an alignment done. Very little needed to be corrected in the new alignment though

My diff is a V-LSD. A very loose/sloppy one at that. However it doesnt seem too bad. This definately would be a part of the problem, but I wasn't really wanting to go down the clutch pack route unless I 100% had to. Possibly shimming will help a little bit in a straight line?

Edited November 4, 2011 by R32Abuser

[Bl4cK32]

how old are the rubbers in the subframe. First thing cubes and i noticed was the thing wanting to twist out of the car.

edit/ welcome to the world of "lets now replace everything that was partially gone to cope with the new power"

Edited November 4, 2011 by Bl4cK32

[R32Abuser]

Subframe bushes in the rear I am due to replace once my HICAS lock bar comes in (couple of weeks). Then Ill be dropping the diff and pissing off HICAS, replacing all diff bushes and replacing the subframe bushes. Hopefully this will fix a few noises and make the rear end a little less "squirmy" when pushing it. In saying that, the diff has ALOT of backlash. To the extent that the clutch shuddering ( I was told for the first 1000km of my JB Full Monty Clutch's life that it would do this) causes some seriously bad knocks in the rear end. Also I can turn the tail shaft like 10 degrees and get little to no movement of the half/stub shafts out of the diff (time for a new diff or at the very least an overhaul of the V-LSD!!!)

All engine/transmission mounts were changed to Nismo items when the motor was removed FYI.

[r31 25t]

I've experienced inconsistent performance when tuning a nistune ecu, (no fault of nistune) turns out I hadn't ticked the "knock copy" box. So basically the ecu had two completely different timing maps available. - Maybe have a look at your main timing and fuel maps and do a quick comparison with the knock maps.

[TiTAN]

i have this all before.

its all in the boost ramp rate and limiting power a little in lower gears (assuming tyres are decent and you arent running something silly ie -5 degrees camber on the rear).

GT35R + 235 semis and i have traction in 1st and 2nd unless its particularly cool/cold

if you can have a 2D map for boost control and run GEAR vs Revs, eg mine runs 1st 15psi, 2nd 17psi, 3rd 17 until ~100km/h and then full boost from there on.

[R32Abuser]

I run a standalone controller for boost controller (Blitz DSBC) which (to my knowledge) doesn't allow such freedom May have to play with the ramp rate overall. Suffer with a little bit more spool time to get a little bit more power to the ground.

Once my Bridgies have run their race Ill definately be moving onto a semi at the rear or all round. Federal RS-R's or Kuhmo KU-36's most likely. I would go to a 255/40/17 but the price difference is rediculous and its makes the wheel setup "technically" illegal as the wheel protrudes from the arch.

[StevenCJR31]

Ok... so having done a few k's with the new motor I have a few issues/observations which I want to know whether they are consistent with what others have noted.

For details of my build please see:

http://www.skylinesa...ge__hl__ceiling

AND

http://www.skylinesa...1076-rb2530det/

FYI Motor is still on castor/mineral oil as I am doing 500-1000km before changing to synthetic.

My first issue/observation is the immediate lack of traction achievable in 1st/2nd/3rd gears

Now although this change is blatantly obvious due to the dramatic increase in torque from my previous motor (RB20DET), I'm wondering what you guys are experiencing...

This is all in the dry BTW:

1st gear is pretty much useless @ more than about 1/2 throttle...otherwise she spins up

2nd gear EASILY torches the tyres when full boost comes in (~3200RPM) and if you don't modulate the throttle to minimize wheel spin, it all just ends up in alot of smoke/noise through to cut-out (7000RPM)

3rd gear will just be able to hold the tyres in line with them spinning up "ever so slightly" until about 5k rpm where power/torque has nosed over (see above post links)

Suspension setup is the Sydney Kid GB. 235/45/17 Bridgestone RE001 rears with probably 60-70% left.

My idea to assist traction would be to go to a 255/40/17 and potentially go to a semi-slick such as a KU36. However, I just don't see these changes being able to make such a significant difference considering the torque. What setups are most members running and what are your observations? Do you guys find that having the additional torque from RB30 and a decent sized turbo that it is just not "practically" useful on the street?

Of course this is assuming we are not spinning the tyres every time we want to give it a squirt below 60-70km/h in 2nd or 3rd.....

Secondly, when ever the motor comes on boost at throttle positions between 75-100%, it almost feels as though something is "restricting" the car. What's moreover is the power that the motor delivers feels very inconsistent. I.e. non-significant changes in ambient temperature- one time the thing will feel like a ball tearer, the next time it will feel "flatter". By no means is it a lesser feeling than say an RB20/RB25 DET setup, but it just doesn't feel as consistent in putting out power as the OEM tune did. Have any of you forklift motor owners experienced said "feeling"? Could this potentially be related to a temperature compensation in the Nistune ECU reducing the timing the motor sees as the engine gets hotter from the previous "squirt"?

Thirdly, as soon as you change gears, the motor feels like the rev's drop SIGNIFICANTLY more than what I would normally expect during the time the clutch is depressed- it's as if the engine is wanting to stall! Now I believe this to be partly caused by some reversion coming from the turbo (NOTE: "chopping" sound after gear change occurs) playing funny buggers with the AFM readings. Intake side consists of stock BOV setup, 3" metal intake pipe (pissed off the OEM rubber item). Any of you care to share your thoughts on this issue?

All in all, I'm happy with the setup but have these few drivability issues to sort through to make this a more comfortable streeter.

Any thoughts/comments etc. are much appreciated

changing to a hub dyno will solve your tyre spinning problem

[StevenCJR31]

Ok... so having done a few k's with the new motor I have a few issues/observations which I want to know whether they are consistent with what others have noted.

For details of my build please see:

http://www.skylinesa...ge__hl__ceiling

AND

http://www.skylinesa...1076-rb2530det/

FYI Motor is still on castor/mineral oil as I am doing 500-1000km before changing to synthetic.

My first issue/observation is the immediate lack of traction achievable in 1st/2nd/3rd gears

Now although this change is blatantly obvious due to the dramatic increase in torque from my previous motor (RB20DET), I'm wondering what you guys are experiencing...

This is all in the dry BTW:

1st gear is pretty much useless @ more than about 1/2 throttle...otherwise she spins up

2nd gear EASILY torches the tyres when full boost comes in (~3200RPM) and if you don't modulate the throttle to minimize wheel spin, it all just ends up in alot of smoke/noise through to cut-out (7000RPM)

3rd gear will just be able to hold the tyres in line with them spinning up "ever so slightly" until about 5k rpm where power/torque has nosed over (see above post links)

Suspension setup is the Sydney Kid GB. 235/45/17 Bridgestone RE001 rears with probably 60-70% left.

My idea to assist traction would be to go to a 255/40/17 and potentially go to a semi-slick such as a KU36. However, I just don't see these changes being able to make such a significant difference considering the torque. What setups are most members running and what are your observations? Do you guys find that having the additional torque from RB30 and a decent sized turbo that it is just not "practically" useful on the street?

Of course this is assuming we are not spinning the tyres every time we want to give it a squirt below 60-70km/h in 2nd or 3rd.....

Secondly, when ever the motor comes on boost at throttle positions between 75-100%, it almost feels as though something is "restricting" the car. What's moreover is the power that the motor delivers feels very inconsistent. I.e. non-significant changes in ambient temperature- one time the thing will feel like a ball tearer, the next time it will feel "flatter". By no means is it a lesser feeling than say an RB20/RB25 DET setup, but it just doesn't feel as consistent in putting out power as the OEM tune did. Have any of you forklift motor owners experienced said "feeling"? Could this potentially be related to a temperature compensation in the Nistune ECU reducing the timing the motor sees as the engine gets hotter from the previous "squirt"?

Thirdly, as soon as you change gears, the motor feels like the rev's drop SIGNIFICANTLY more than what I would normally expect during the time the clutch is depressed- it's as if the engine is wanting to stall! Now I believe this to be partly caused by some reversion coming from the turbo (NOTE: "chopping" sound after gear change occurs) playing funny buggers with the AFM readings. Intake side consists of stock BOV setup, 3" metal intake pipe (pissed off the OEM rubber item). Any of you care to share your thoughts on this issue?

All in all, I'm happy with the setup but have these few drivability issues to sort through to make this a more comfortable streeter.

Any thoughts/comments etc. are much appreciated

changing to a hub dyno will solve your tyre spinning problem

[TiTAN]

he isnt talking about on the dyno.

[R32Abuser]

FYI

Found an issue with my knock sensor fault occuring.

Hence, this has been pulling timing when the fault occurs. Apparently the fault stays on the computer until you turn the car off for about 10 seconds. But either way, it does explain the "inconsistent feeling" of power I described.

[XKLABA]

what diff ratio are you using ?

[R32Abuser]

OEM R32 gtst gearing...4.343 IIRC?

[JonnoHR31]

4.375 usually

[XKLABA]

OEM R32 gtst gearing...4.343 IIRC?

I would suggest getting 4.11 or even the 3.9 when you do the lsd so you can take better advantage of the mountain of torque you would be making now

[DVS JEZ]

What ecu are u using?

[R32Abuser]

NIStune...