Speedworks tuned R34 talk

[hks-s14]

XRW - what happened to the 34? Blow an engine?

[Denver]

Originally posted by hks-s14

XRW - what happened to the 34?  Blow an engine?

It has spat the motor as most know, the failure atm seems likely to have been caused by the lack luster machining that was done on the block, and a few others at the time until the lack of quality in the machine work was discovered, anoyingly it blew just before the motor was going to be pulled out, checked, and the problem with the poor machining work, if it was there, resolved, (owner wanted to go for a last few runs at the drags before he went home for a holiday).

It should be back in action shortly, the other problem with it is the stock gearbox, and the 99% chance it will fail shortly due to the power output of the motor, a dog box is the owners next purchase, and that will take somewhere between 8-12 weeks to get one made within oz, and a few weeks to source a unit from japan, and given the hasles the stock box gave when it ran 11.1, itd be better to have a box that will work cleanly so as to make a full power pass worth while of getting kicked out, itd be anoying to see it go just under 10.99 and not do a run near its full capabilities, which is somewhere down to a very low ten and possibly on a perfect run, a high 9..

[ix9]

Originally posted by XRW

(owner wanted to go for a last few runs at the drags before he went home for a holiday).

Explain to me then why you "get to drive it" ?

[N I B]

Should have been properly inspected when assembled.

[hks-s14]

Bad machining hey... bugger. So what was machined badly that made the engine pop?

Must be an expensive exercise...do speedworks get insurance for that kind of stuff or can claim it against who did the machining?

[Denver]

Originally posted by Strich9ine

Explain to me then why you "get to drive it" ?

The owner isn't that confident with going flat out, and doesn't feel he has the ability to make the car do what it can do just yet..

That and hes a bit of a voyer and likes to watch it in action going in a straight line i guess..

[Denver]

Originally posted by Steve-SST

Should have been properly inspected when assembled.

When it went together there wasn't the time to spend a few hours checking all the measurements, not with the 2ic of JUN waiting there to tune it, and as the machinist gave his word that the machining would be spot on, it was trusted he did his job properly..

The same comment could be made about adjusting timing with a ratchet, and not bothering to check with a timing light to see the original timing and the new adjustment, but i won't point that out will I..

[Denver]

Originally posted by hks-s14

Bad machining hey... bugger.  So what was machined badly that made the engine pop?

Must be an expensive exercise...do speedworks get insurance for that kind of stuff or can claim it against who did the machining?

Excessive ovalation of the bore, outside of the allowable tolerances, causing blow by and excessive piston slap..

and the car is being repaired at no cost to the owner and the matter being taken up witht he machinist, along with the other work that he did which has failed..

[N I B]

Denver please re read what you wrote, best say nothing

than that excuse. CAS bashing has served me well with no

problems even helped poor imported tuning.

[rev210]

I have moved the CAS without a timing light plenty of times. After a while you get an idea of where the thing should be based on the engine response. I can't use the timing marks anyway, I've gone right past them.

Steve-sst, you obviously tune the right way. Use response/power and engine knock to determine optimum timing. The timing light doesn't tell you jack! It tells you what the timing 'is' not if it's too much or not enough.

[Denver]

Originally posted by rev210

I have moved the CAS without a timing light plenty of times. After a while you get an idea of where the thing should be based on the engine response. I can't use the timing marks anyway, I've gone right past them.  

Steve-sst, you obviously tune the right way. Use response/power and engine knock to determine optimum timing. The timing light doesn't tell you jack! It tells you what the timing 'is' not if it's too much or not enough.

Rev, and your original reference point is?..

its good practice to check before and after where you have started, its all well and good to move it, but what if you wind on some 10+ degree's of advance without knowing it and suddenly get detonation, its a bit hard to go back to where you began if you didn't check it..

power and response may be better, but at what cost if it starts pinging because theres to much advance..

[GTS-t VSPEC]

It's nice to have a point to go back to, incase you stuff it up even worse, I just mark my starting point, so I know I can always return to my original settings.

See'ya:burnout:

[ix9]

I thought you didn't even use the CAS for timing paul, doesn't aftermarket management handle that ?

[rev210]

XRW,

I've had a timing gun on my car before, made a mark on the CAS.I know the position so well I don't even need to look at the mark.

I don't need the timing light as a refference.

If I over advance I will pick that up long before I get a ping, thanks to the knock sensor. The CAS is where I make the mark for refference/starting point. The timing light can be used to make experimental adjustments in increments in the same way as rotating the CAS.

There is an ideal spot for timing that doesn't ping and gives extra response, I don't need to use a timing light on my car right now to do that.

How do you think you improve timing performance with just a timing gun, you would certainly agree with me that it can't tell you anything important as far as thats concerned. What you need is the engine knock and some sort of power reading to determine if you are advanced too far or not far enough.

Perhaps we just misunderstood each other. I appologise if I am stating the obvious to you to get the point across.

[GTS-t VSPEC]

Strichnine,

The computer still uses the CAS as a reference point, so although the computer chooses the timing, the signal from the CAS is still used.

See'ya:burnout:

[N I B]

On Pauls GTS we chased peak HP and torque at each load

point while tuning then when finished I do a power run and

then advance the timing with the Wolf then retard it and see

where we gain and lose and then set the perfect ign map.

Nissan CAS only fit one way and are very consistant and as

I see many every week you can judge the advance at a glance.

Who cares where the timing was when you have the Dyno

to test the result any way.

[hks-s14]

and the car is being repaired at no cost to the owner and the matter being taken up witht he machinist, along with the other work that he did which has failed..

Ohhh so not a once off incident. Hopefully you won't be using that machining shop anymore. Unbelieveable that they can stuff up that much when it comes to something as simple as machining.

[Denver]

Originally posted by rev210

XRW,

If I over advance I will pick that up long before I get a ping, thanks to the knock sensor. The CAS is where I make the mark for refference/starting point. The timing light can be used to make experimental adjustments in increments in the same way as rotating the CAS.

There is an ideal spot for timing that doesn't ping and gives extra response, I don't need to use a timing light on my car right now to do that.  

I understand you exactly where you comming from, my main point being that every car is different, and a twist on the CAS can result in anything from 1-2 degree's to 10-15 degree's of advance in one foul swoop, given the nissan ecu in stock form will detect the knock long before it becomes a large ping, but this will only result in a loss of power not a gain..

im just a fan of checking simple things like that, and as you said it, every car will have a nice point where it gets good power and response, but won't put the engine in the danger zone of detonating and knocking causing the ecu to knock everything back down..

main point being that unless as you have, done it a thousand time on the same car, checking first then gradually moving things around until it seems spot on, then checking again to see where eveything is set, is smarter than unbolting, twisting, and having no idea if you just wound in 5 deg of advance, or 15..

[Denver]

Originally posted by hks-s14

Ohhh so not a once off incident.  Hopefully you won't be using that machining shop anymore.  Unbelieveable that they can stuff up that much when it comes to something as simple as machining.

Well yeah, the other motors that failed where sr20's owned by the guys at speedworks and not as in the case of the 34, a customer car, and basically the same problem, bores to out of round and incorectly tapered, but in this case, these sr20's had liners installed to handle the extra power demands, and due to the nature of the liner being interferance fit, and the bore holding the liner not providing the right amount of interferance, the liner moves around, breaks the seal with the head gasket, and water get into the bore..

they've since changed machinist and are religiously checking every bore that comes in now for ovality and taper, anoyingly in the case of the 34, every other measurement got checked, eg bearing cap crush ring gap etc etc, the only thing not check was the ovality and taper of the bore, something im sure 90% of motor builders wouldn't check as the assumption is that the machinist has done his job right..

whats the saying, assumtion is the mother of all stuffups..

[C-Red]

Dude,

I've heard 50 micron being bandied about as the figure that the bores were out - that isnt going to kill a motor if its 50 micron bigger than it needs to be - only if its 50 mic smaller...Besides which 50 micron is that small that it would almost go through a fuel filter and be burnt in fuel.

The problem to me sounds like the car was tuned too keen too quickly, but hey what do I know about tuning a car - I'm not Japanese.

Dont knock CAS knocking - it works alright for us and SST, and I cant remember a car that we've tuned going bang at the drags.

Jash