rx-line
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Posts posted by rx-line
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What compression pistons?
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1 hour ago, GTSBoy said:
Trouble with your example is that the 4WD box you have is strong like a GTR box.....effectively the same as the R33 25DET box.
The normal RWD RB20DET box is definitely nowhere near as strong as the R33 turbo box. It's about half the size and weight. I trashed the input shaft bearings on 2 of them with only mildly more power/torque from the RB20. There was no way I was going to run a 25 without the matching.
To the OP....you _might_ get away with running the 20 box because the RX7 is so small and light. It immediately presents that much less load to the box.
A Stagea engine will work. The AWD sump is the biggest hassle. As you were told above, don't use the 20 ECU. Just use the Neo ECU with Nistune. Much better. If you use either engine (2WD or AWD) you have to use Nistune to keep the Neo ECU happy with the lack on inputs from the original car's ABS/TCS anyway.
Yeah, making more sense to pay for the rb25 box.
Have killed 3 RB20 boxes so far. Running launch control,slicks, 6 paddle clutch and 1.5sec 60 foots royally dicks them. Usually Synchros wear off making the shift to second at full load near impossible, shift to third is none to great. I have broken shift forks as well. At the power I'm pushing in the 20 you'd be lucky to get weekend at the strip. Car weighs 2600 or so, ford 9" rear.
I've gone so far as to do the 6-8 hour job of re-building one, didn't last a whole lot longer than other spares I had.
I was going to continue with the 20 but the r25 tranny is a must and at that point it's too cheap not to get the engine. I like to idea of the using R34 ECU and wiring harness, hopefully they will send me a fuse box with the harness.
Just trying to get into the 9's
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Actually I was looking, the Stagea did not have TC correct? The one I am looking at does not have the large cylinder off of the throttle body. So that would make it a Stagea engine?
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RB25DET NEO , AWD vs RWD trans
Looking to swap my RB20det with an RB25det NEO and run the RB20 nistune wiring / ecu as it is in an rx7. Push to Pull Conversion, Intake manifold, shaft yoke etc. differences aside.
However the dilemma arises when shopping the Canadian market for the engines. My biggest issue has always been the weak Rb20 gearboxes. Keep in mind I have the ability to modify the transmission & oil pan and that I will have to increase the driveshaft tunnel size anyway.
All long blocks with trans, turbo, ecu etc.
RB25det RWD S2 - $3200.00 (Don't really want anyway)
RB25det RWD Neo - $2800.00 (Preference)
RB25det AWD Neo - $2200.00
First question, do the AWD versions only come in Stageas? Or was there an R34 GTS-4? As it is advertised as coming from a skyline.
Does the AWD version feature the same transmission from a R34 GTR? I.e same transfer case, gear set, 6 speed, etc. If so is it stronger than the RWD box?
Lastly is there any mechanical / electrical differences from AWD / RWD besides oil sump? I heard something about Traction control on factory ecu being different, but likely won't effect me unless I maintain current harness for some reason.
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2 hours ago, Dose Pipe Sutututu said:
Add more boost.. ring lands won't blow if you limit torque. Also spray more fuel at peak torque to keep the cylinder temperatures down and pump in more timing as torque decays..
I think the excess cylinder temps cause the rings to expand then smash the ring lands not so much the pressure/force.
Because you even hear of people smashing ring lands with cars making 250kW.
To put things into perspective, I've been thrashing the shit out of my car with about 1.8bar through the motor on the track and it's yet to go boom LOL... but like I said, I run very low timing at peak torque and spray heaps of fuel to the point it is about to misfire... but, the car is happy and the only thing that has died is the stock 300 000km head gasket and the turbo's arse end exploding.
Good point, progressive timing and rich fuel definitely helped my RB stay together for as long as it has. Heat is definitely the culprit in ring compression / failure, but the quickest way to heat is often cylinder pressure ( Boost, compression, nitrous, etc.) assuming everything else is fine?
More Air = More Fuel = More Pressure = More Heat, I think i'd be right in saying that.
1.8bar would be relative to the amount of flow, what turbo are you running?
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How tough are the automatics in these? Really don't hear much about them.
Most basic autos with some miles don't seem to like a bunch of power added and start to slip. However a skyline auto is likely much tougher than the auto's I've had experience with.
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I wouldn't be going past 25psi, typically stock rings are not meant for such high cylinder pressures. Especially in an engine known to have ring land issues In theory you would no want the rings to touch and compress on one another. I'd be looking at other items rather than boost pressure to hit 500hp.
In my RB20 this year I did about 12 runs in a weekend at our local strip. I was upping boost constantly and ran a 10.67 twice with 25psi @ 131mph and 27psi @ 133mph (Different 60 foots). I then proceeded to run 29psi and 30psi. The engine still works "fine" and is fully standard stock internals, however it has a fair amount of blow by and I suspect piston failure due to cylinder pressures.
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On 12/1/2016 at 11:20 PM, Jonic said:
Now everything it out back together the car runs but the PROBLEM OF THE LIMP MODE IS STILL THERE !! I can't even rev pass 2000rpm, even when parked! Something must be playing up and I'm thinking it's the AIR FLOW METER. Ever since I changed the Pod Filter the problem started, but the thing is I changed it back to normal but it's still limping, I can't even hit 60Kms on the road :0
When my MAF was bad the car wouldn't rev past 3000rpm, it made my car run rich and when I changed the MAF it did not run right as the plugs were fouled. Thoguht I would share that. Pull the MAF sensor plug while the car is running, should make a difference on AFR's, idle speed etc.
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From what we can tell the only thing changed was the filter, I would look at the Maf extensively to check for damage.
My car would not start and sputtered going into boost when the plugs were fouled. Also check for ground wire to coil packs/ignitor.
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6 hours ago, jas/slo32 said:
Hahaha I guess this one takes the cake as there are no classes for RB20 powered cars.
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Threads need to be lubbed in order to keep the steel alloy of the stud from galling the aluminum, this will give an accurate torque, rather than a false torque if galling has occurred. A false torque could cause a leak for sure.
Also you might want to try torquing from the inside working your way from side to side to the outside of the head, we have had good luck with this.
As for a reason things change a fair bit when you clamp a head to a block, it's surprising how things move. If the above fails I would look at the head and block to see how well they have been surfaced.
Here's a thought as well, you might be experiencing above average crank case pressures due to you rings not being seated in with the new build. Make sure not to use synthetic oil when breaking it in, it delays the process by a lot. This may be exaggerating the leak.
Hopefully this may help you.
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Get a wideband, and a fuel pressure gauge, actually these should already be in your car.
They help immensely when troubleshooting as you can drive down the road and help determine things like fuel filter, fuel pump, ignition issues etc. You can also see if your fuel pressure correlates with an issue in AFR, if they don't match than it could be an issue ECU/vaccum side. Rather than just opening the hood and looking for issue that can't be seen.
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A strut/spring setup in the rear with quick/light compression and slow rebound will allow the car to squat and transfer more weight over the rear wheels. I woudl think the front would have a stiffer spring with high rebound in contract.
This is what I can gather however.
I can't tell if you have slicks or not but I went from 1.7's to 1.5's in just learning to use them properly (proper burnout heat). Also doing your burnouts in the water box will coat your wheel wells in water and when you get to the line and stage it drips down on the tires! This is bad.
Also slipping the clutch off the line will cause you to get off the line super quick and without spinning tires if done right. Really a hard thing to master.
Do you have launch control? what RPM are you leaving at? What tires are you running>?
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I'll see if I can upload a video to youtube at some point. Here's some pictures for now. It was fairly close to lifting the front wheels in first and when hitting second as you can see in the photo. Higher launch control, a bit more power and some suspension tweeks might do it. The cars got some blow by issues now but still runs fine. I think I might make the jump to an RB25 neo as I need the bigger transmission anyway (been through 3 RB20det trans, typically synchros get chewed off within a weekend or you break shift forks).
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RX-7, fully legal street car, slicks, Ford 9", fully adjustable coilovers. I ran this time with a crap reaction time, The car can do low 10's I'm sure.
RB20DET - Stock Internals, Stock headgasket even. No cams, no cam gears, no bullshit, never opened.
- Hy35 Holset
-Tial F38
-GFB Gforce 2 EBC - 25-27PSI
-Nistune (Launch control 5800rpm, could be set higher)
-Custom in-house Intake and Turbo Manifold
-Vibrant intercooler
-GM 75mm Throttle Body
-4"- 3" down pipe, 3" SS exhaust
- 2.5" - 3" intercooler piping
- RC 720CC injectors
- Custom Driveshaft
- RB20DET transmission (On my third, looks like I need a 4th).
List goes on.
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RB20DET 1/4 mile World Record?
Anyone know the record for an RB20det powered vehicle? I recently ran 10.67 1/4 mile in my RB20 powered rx-7. I would have to assume an 8 or 9 sec car.
Is this documented?
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Hard to say, if I had just seen the charge piping only I would have said the clamp was over tightened. However like others taid the clamps where too tight, it got hot and some engine movement occurred pushing the charge piping up against the compressor housing. I would leave a 3/4" gap between the piping and housing next time. Also check your motor and transmission mounts.
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Hard to say, if I had just seen the charge piping only I would have said the clamp was over tightened. However like others taid the clamps where too tight, it got hot and some engine movement occurred pushing the charge piping up against the compressor housing. I would leave a 3/4" gap between the piping and housing next time. Also check your motor and transmission mounts.
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Hard to say, if I had just seen the charge piping only I would have said the clamp was over tightened. However like others taid the clamps where too tight, it got hot and some engine movement occurred pushing the charge piping up against the compressor housing. I would leave a 3/4" gap between the piping and housing next time. Also check your motor and transmission mounts.
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22 hours ago, GTSBoy said:
Dude,
As I said above, latency is measured in microseconds. The difference between one injector and another injector is a few micro seconds (alright, a few hundred microseconds). Adjusting latency is not a tuning tool for setting the start/end timing of the injection event. it is just a tool for making sure that the delay in the injector opening is accounted for when calculating the total injector opening time. A Nistune ECU does not offer you the ability to set either the start or end time of the injection event. it happens on the schedule decided upon by Nissan when they designed the ECU. If you want to play with the actual injection end point (which is what you really want if you're aiming to time it in some specific relation to valve opening or to try to avoid whatever fuel pooling scenarios are running through your nightmares) then you need an aftermarket ECU that gives you that knob to turn.
With respect to trying to tune the injection end point and/or minimise any fuel pooling, keep in mind though that unless you injectors are quite a lot larger than you need, you only have ~16ms to get your injection even done at the top end of the rev range and your injectors are therefore open for a very significant fraction of the total time available, thereby negating most of the perceived benefits of careful event timing. Careful event timing is really good for optimising cruise and mid rev range performance.
Missed your first post. I had questioned this myself, but proceeded to assuming latency had more of an effect on injection timing.
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Running a He341 (HY35) Holset on my RB20, fair bit of lag but full boost by 4500-5000rpm with a slow taper starting at like 2500rpm 1 psi. Peak efficiency something like 27psi, indestructible for the most part. The RB20 really doesn't do much with the boost it makes below 4000rpm, a bit of a pig either way.
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13 hours ago, zebra said:
Pooled fuel is bad mang!!!
Needs to stay in suspension, fuel pooling can show as an engine being stupid rich but still detonating like it is lean.
Ideally you would pulse the injector just as the valve is passing 1mm of lift so their is airflow past the valve.
This was my thought, just as the fuel/air entry was almost at the valve, the valve should be opening. So far injection timing is only related to detonation and not power?
For these RC injectors I was told to get them to the point where they were spraying a little early for best idle.
However in say an ECU with tunability like nistune, would setting my latency to match my injectors (Suggested Latency) be optimal? I.e. Spraying "the injector just as the valve is passing 1mm of lift so their is airflow past the valve." Does Nissan do this from factory? Assuming everything is in check.
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As well I am thinking ignition timing would have a large impact on injection timing as well?
9.5:1 RB26 Dyno Results
in Forced Induction Performance
Posted · Edited by rx-line
I've been using the search function a bit and the higher compression engines seem to be more common on the RB30 builds.
Does anyone have dyno results for a RB26 in the 9.5:1 compression range or can point me in the right direction? 64-70mm turbo, ported head, cams would be helpful.
Thanks,