rob82
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Posts posted by rob82
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I reckon there would be enough room to get the LS2 or AEM coils under the coil covers. You coud allmost just use cut down OEM LS2 coil leads too.
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Rebuilt engines with power FC?
Mostly STD engines....
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I found on my gtr apexi djetro on a low load ping read about 20. I occasionally still get over 100 on crank I presume from starter motor mesh? The base ignition map has a lot of low load advance. After some fiddling now I never get more than 12. Reset max timing to no more than 32 (was 48) and varified number with timing light. Bp98 always used.
I've heard plenty of RB engine's ping at low rpm high load and the knock sensor hasn't reacted, thats tuning with either PFC or factory ECU. I wouldn't recommend tuning based off feedback from the OEM knock sensor, use it only as a guide along with a proper chassis ear and good understanding of what an engine does when it is detonating.
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You answered your own question... OEM's are tight quench, high compression engines for a whole bunch of reasons not directly related to big horsepower. Efficiency across the whole rev range, emissions, etc
In terms of making big horsepower in a boosted application it is far from different. No quench and lower compression (lower is very subjective) and obviously high boost pressure is favoured.
I can see the appeal that the OEM's go for and also what others do on here with their builds; but for 500kW throw that approach in the bin.
What would car manufactures know about building engines.....
Every new model needs to make more hp, less emissions and better fuel economy. Changing to a higher compression ratio is not an easy change considering the extra thermal loading on turbo chargers and catalytic converts coupled with the potential for higher NOx levels and less resistance to knock. They usually run high quench zones to promote central flame propegation and the fact that detonation usually propagates at the outer edges of the chamber. Look at the 335ci engine or L3T mazda engine or VW golf they are all running high compression ratios couple with Direct injection.
Now when you have a higher octane fuel - in order to achieve the full affects of a highly knock resistant fuel is to increase the compression ratio. I dont see the point of running "big boost" when all your doing is running the turbocharger outside of its effciency range.
And average cylinder pressures dont increase expotentially with power... You would probly find that a well setup 400kw car would have similar cylinder pressures to a 500kw car, its just the 500kw car has higher cylinder pressure at a higher rpm.
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Forget high compression if you want big boost... waste of time. The small amount of hp you will make lower off boost will not offset the amount you could make by winding the boost up further and not having any issues.
Lower compression and no quench for big power and high boost.
Well that's definately a different way to look at things.... When was the last time a high performance car manufacturer reduced compression ratio or quench in a newer model?
Higher compression will make the engine more efficient everywhere. Now couple that with a highly knock resistant fuel and you will have a good engine. You need to look at your compressor map and see where the turbo needs to run and then choose the compression ratio based on the fuel and boost you need to run.
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I would be more worried with block integrity than cam choice.
I think you could achieve that power with a smaller turbo and a well setup engine on e85. (gtx35r, 10:1comp and around 256deg cams at 10mm lift)
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I can't see the intake manifold being the best place for that sensor (WTF were Nissan thinking?).
Anywhere between the cold side of the cooler (where you have circled) and before it hits the engine bay. That way it doesn't get warm from heatsoak.
Makes sense to me. Closer to the chamber the better.
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Cmon dude, flowing the intake? It's a motor that now has low comp due to an internal failure. It's pointless, and even if it was the manifold, how would you link it to a failure like low comp? Doesn't make sense.
You should be able to see signs of det with a bore scope. Even if the crown has nothing, it has low comp which means rings, which means the bore will have drag marks all over it where the rings lands have failed.
When I said clearances I said probably, which means it may or may not be that. Just about every second failure I have seen has been either:
1. Incorrect ring clearances
2. Incorrect bearing clearances
I would put money on it being either of the above, pending it's a well known tuner, who of course ran it up himself.
If the manifold favors cylinders 1 and 2 then it is likely that these are the lean cylinders - which most likely means you've overheated(melted) a couple of pistons. Hence the comp will be low.
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Flow testing the intake is just the builder/tuner postponing the inevitable, which they both know is finding the real cause of the failure and deciding who's going to pick up the tab. It's not going to tell you anything, and it won't be the plennum at fault.
I would be asking to view the det damage personally through the scope, it's pretty easy to see as the crown of the piston will show signs straight away. If there's no det damage then the ring clearances were probably wrong, and you need to do a leak down on all cylinders. If it's a fairly well known tuner, then I doubt there to blame.
You need to get personally involved in finding the cause, otherwise your just going to get fed BS like flowing this intake.
That's a pretty bold statement. Have you seen the intake manifold to make that conclusion. Generally unless you've overheated the crown you won't notice detonation via a borescope. If you dont know what your looking for then get an independent failure report.
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I've run N1 pumps for 8 years, 3 now over 3 builds - don't smash the limiter and you won't break them.
That said, i did smash limiter constantly and never broke one either (on the recent build from 2 years ago, no problems).
But that's another debate entirely really - use the search and form your own opinion on the matter is my best suggestion - there are only a few people with broken ones and a lot without.
Yes but I bet your engine builder torqued the crank bolt up to factory spec.....
So many don't - that's where I believe the issue lies, as it will induce a load at 45degrees to the axis of the crank when loose. Problem only really exist on short drive cranks.
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Plug 740 engine hp (which is approximately 505rwkw) into any ET calculator with 3500lb car and your pretty close to 136mph. So I would say the dyno figure is pretty close to 136mph....
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i got before & after dyno graphs on the GT35R & GTX35R...
all i can say is the GT35R @ 112Klms makes 145rwkw
GTX35R @112klms makes 225rwkw
Torque is a much flatter / longer
What fuel? That's good power.
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Isn't it easier to ignite the air/fuel on an engine that has a much larger bore like that one?
Yep - generally the higher the torque the greater the cylinder pressures so the higher harder it is on the ignition system...
I haven't try these coils on an xr6t, because they wouldn't fit very well but the are probably one car that really pushes a coils ability and I know just the car to test on. If I get to test them on that car I will let you guys know how they hold up?
Also the only other downside is that they aren't cop...
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They look like awesome coils. No CDI or igniter unit required. Less to go wrong?
How have they performed for you rob?
Why do you not like CDI systems? Because of the electrical interferance and low dwell time?
I'm about to turn up the wick on a certain engine that will be in the vacinity of 2000hp with these coils - currently at 1260hp and no issues with 1.1mm at 18psi. Have seen them not misfire with 1.1mm gap at this boost with mixtures as rich as lambda 0.67.
CDI is good if you want high peak secondary current and minimal dwell time - issues I have with CDI is eletrcial interference and low spark duration coupled with extra cost. Only thing with these coils and LS2 series coils is the dwell time can be as large as 5ms at 14V for full spark energy which can be a bit much on non sequential setups with rapid accelleration rates and flat shifting. Doubt most people would run into this issue though.
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If the volume of the plenum (volume between tb and runner division) is large enough it won't be an issue.
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I haven't seen inside a VQ but I imagine being a later design its burn characteristics are a bit different to most RB25/26 engines . Except for Neo 25s I don't seem to remember the 25/26 chamber design changing much if at all . I don't think they were intended to be ultra low emissions engines and probably don't cope super well with lean overall mixtures . Obviously Nissan put some extra development into 25 Neos to get them to run reliably as a ULEV engine .
Big plug gaps tend to like very high voltage ignition systems and thats probably what it takes to fire lean mixtures reliably , always assuming the engine doesn't detonate with the higher associated combustion temps .
I have limited experience with these high ethanol content fuels but from what I can hear and feel ethanol fires quite easily . Perhaps the greatest difference between E70-85 and 98+ octane petrol is that its a higher octane fuel but unlike high octane petrol its not hard to light up . The detonation resistant properties of high octane petrol actually work against it when it comes to lighting the fire .
Anyway back to my goals , economy at all cost is not what I seek best torque at all engine speeds and loads is . My aim is to not use any fuel beyond getting the most torque I can everywhere .
A .
Your correct, generally big gaps require larger peak secondary voltages due to the increase resistance and yes as the equivalence ratio decreases the ch3 ion reduces meaning it's even harder to fire. Don't assume that the chamber temps will go up with lowering equivalence ratios as it normally not the case but can be so on slow burning chambers.
Unfortunately though ethanol based fuels do have a lower Reid vapor pressure and high flash point than normal 98oct fuel meaning that it is harder to ignition or less volatile - hence the reason cold starts are difficult under 12 degrees c.
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http://www.aemelectronics.com/high-output-igbt-inductive-smart-coil-1240
This is what I would use - best inductive ignition system I've seen.
I tend to prefer running inductive ignition system compared to cdi on almost all applications - especially on street cars.
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No what I was looking for some sort of Lambda reference to petrol AFRs which had some meaning for me . I'm not interested in being any richer than does any good in the light load areas because that costs money for zip .
I can tell you that leanish mixtures under load feel weird with this fuel and not really like a leanish petrol situation . No cough spit or rattle just a torque fluctuation from probably low combustion temps and pressures .
Being able to read EGTs would be great but how many normal people have access to the gear or even know what the ideal temps are ?
Yesterday I put more fuel back into the low medium load areas which helped made more torque and put the Lambda numbers up to what I now think they need to be . Later today I will do the same a bit higher up the engines rev range because I'm getting to know what leanish mixtures feel like to drive with but the wide band will show for sure .
I think this is going to be one of those times where adding more fuel in the right places gives better consumption because lean isn't always economical .
Also going to have to resort to a serial cable because this laptop is doing blue screens with Datalogit when the engine is running , seems ok with the ignition on and the engine not running with their supplied USB converter cable .
A .
Being on the lean side in a SI engine will generally always improve fuel efficiency as your reducing your pumping losses. I would be looking running around 1.1-1.2 lambda and see what you get. Yes the engine will feel less responsive but you will increase your fuel economy. I would also run the largest spark plug gap you can to help complete the burn.
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I think its more a case of knowing what they mean as in elec load vs no elec lod load fuel resumption revs and elec load vs no elec load idle speed .
I had the Tech Edge wide band back in mine today and as I thought it was running a little lean in the light load low to medium engine speed areas .
I richened up the very low engine speed areas when loaded ie 400 and 800 rev colums at higher airflow rates . Thhis makes the idle torquier and less likely to stall with very small throttle openings when moving off . With the fuel resuming at 12-1300 revs nothing I did fixed the bucking kangarooing problems I had .
ATM I'm idling at 1.01 - 1.02 Lambda but it can go lean towards 1.08 at hot restarts which doesn't give any drivability issues . Light load cruise is around 0.98 to 1.00 L . As the load ramps up its falls to 0.95 and around boost it gets into the 0.92 to 0.85 range . If I go WOT as it comes on boost it gets to 0.80 L and I had to look up petrol L/AFR to see what it equates to .
To save you looking the tables I found show this
Lambda .....Petrol AFR .... E85 AFR
0.75 ...........11.03 ............. 7.32
0.80 ...........11.76 ............. 7.81
0.85 ...........12.50 ............. 8.30
0.90 ...........13.23 ............. 8.79
0.95 ...........13.97 ............. 9.28
1.00 .......... 14.70 ............. 9.77
1.05 .......... 15.00
I'm getting a better handle on what the E85 Lambda numbers mean but I had to go back and search for some petrol Lambda numbers to see what the corresponded with in petrol AFR . I did go to start a new thread on Lambda vs AFR but I didn't think too many would be interested a didn't post it .
Something I would be interested to knoe is Lambda numbers with E70 because most of the tables and calculators only show E85 and Lambda = 1 or 9.77:1 AFR . Logically E70s chemically correct mixture would be a slightly higher AFR number because of its higher petrol content .
The difference wouldn't be huge but if we could gain a slight consumption edge thats not a bad thing .
Just on cost I love paying $1.15.9 for Eflex when its cheap compared to Ultimate 98 at $1.70.9 when its not . I think in rough terms I'm paying 2/3 the price of Ultimate was a while back and getting 3/4 of the consumption I used to get though my petrol tune wasn't real good . Eventually I will go back to Ultimate just to clean my petrol tune up but overall I prefer the Eflex E70 .
Ongoing , cheers A .
I'm not sure your getting what lambda means... I think what your really searching for is the leanest mixture you can run without causing drivability issues or engine component failure?
I think what you really need to do is to compare egt's vs lambda and find the sweet spot it will vary more so with load.
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I get it you "know" the 40rwkw gain means something was wrong with my car before
not sure what else I could have done car ran fine before apart from the idle down issue
magic powers are always hard to beat but here goes
what you don't get is that it doesn't matter either way I wasn't trying to prove the air flow meter swap will make more power
no ones going to post result with responses like this you have to retune to car to suit so any gains or losses the tune can be pointed at
I can delete the dyno pics if you like seems it would solve the problem?
I think what ash is trying to say is that if you have a perfectly tuned car running a z32 and convert to an r35 sensor in 80mm pipe and retune you will not pick up any power(in a single turbo/afm combination).
Believe me I've tested so many aftermarket parts that don't work. My view from being a tuner is that if you can change a part and gain nothing in just changing the part over it is unlikely that tuning will make any difference....
Note I've run a single 85mm delco maf sensor up to 14000hz making close to 400rwkw (harrop sc ls1)and done nothing but remove the intake pipe, so "unrestricted" 90mm intake and mafless tuned and I gained no hp what so ever....
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If it is anything like the VQ afm's... They have a microprocessor inside them and fail regularly.
I would be well surprised if they have microprocessor in the afm... May have some kind of signal processing. I know the output is just a typical 0-5v output.
As for tuning i wouldn't be setting it up on a 380kw car - I would get a fairly un modified car and try to map out the bottom end of the curve.
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A lot of the newer style afm run a sample tube rather than just hanging the element in the airflow. This helps to stop the issues seen with airflow reversion.
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ID1000's huh
It would need to be C16. He doesn't have enough injector size to make that HP on anything else
Yeah that power on e85 with 1000cc inj on an rb26 sounds a little high plus that turbo is only rated to about 680hp worth of airflow too. Must have the world most efficient engine....
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If the circuit is protected by the standard size 15A fuse then its unlikely you will burn anything apart from the fuse itself...
Be interesting to see what voltage the pump is seeing on your setup with stock wiring, i'd say you would be very close to the limit. Might be an idea to carry some spare fuses!
Wow that's a pump, over 5l/min at 80psi - that's awesome!! Anyone tried one or got a cost?
Sorry just read the thread - have you tested the return flow to see if it matches the specs?
Hks V-Cam & Link G4? Yes We Can! Thanks Again To Chequered Tuning
in Forced Induction Performance
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Seems weird that they wouldn't mechanically limit the maximum camshaft phase angle on STD engines. I hate the though of software controlling the maximum phase angle. I've had to do the same thing on some of the 3v ford v8's when they upgrade the camshafts - never had any issues but still make you nervous.
I'm assuming 50% drive is your neutral position? If so make sure you limit your max and min pwm drive to around +/- 10% from your neutral drive. Not sure if you can setup cam error tolerances with the link but you would probably want that too so that if you error is too great for too long it will go back to neutral drive. Be careful with running too much proportional gain and make sure you inhibit control below say 1500rpm.