Jump to content
SAU Community

Recommended Posts

  • Replies 73
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Posted Images

Is that in reponse to my #1?

If that is the case, then I am not sure that we are talking about the same thing.

With the longer rod, the piston is around TDC longer for the same number of crankshaft rotation degrees. Hence “around longer” means while the combustion is actually occurring, That’s why I say “Thereby giving an increase in combustion pressure, this means more torque per firing”.

The angle of the rod at ½ stroke is something altogether different. Where the longer rod is also an advantage as the right angle to the crank occurs earlier in the combustion process. Therefore imparting more torque at that time.

Or have I missed something?

:( cheers ;)

With a lower rod ratio, the rod will be normal to the crank earlier in the combustion cycle, not later (ie. closer to TDC, meaning more force transfered to the crank pin and more torque.

But I agree with you, if you want an engine to last, especially at higher rpm, longer rods are better.

This page explains it well: http://e30m3performance.com/tech_articles/...namics/dyn2.htm

Hey guys, once again thanks for the interest, when i started this thread i thought the interest would centre aronud the gt-rs turbos, as these are always the centre of debate...

Again though please dont think im trying to say what i've done is ultimately better than using a brand new jap brand stroker crank, most of those cranks are a real nice bit of gear. However, value for money i may be able to compete on. For me it was just time as i have all the equipment at my disposal, but im in the midst of trying to figure if i can do this conversion at a cost that is both economical to me and to customers. To do this ill have to be well under the price of those kits. Im thinking that this conversion is good for people who've just trashed a crank through oil surge, and are looking at building a new bottom end, and need another crank anyway. One other thing to think on is while my crank is not fully counterweighted, this may be a good thing for a drag application, as fully counterweighted cranks are quite heavy. Lightweight cranks are always limited life but for drag work often this is not a worry

We have GT-RS turbo's and will change back to 2530's if i can't overcome the lagginess (is that a word) of them. Larger capacity seems the only answer.....or a shot of gas off the line to spool them up quicker. mark99 our car is drag only so may be a candidate for your crank upgrade.

Disclaimer: The above post could be and possibly is total bullsh1t

While on this GT2530/GT-RS(2871R-52T) has anyone thought of using HKS's GT2535 turbo's ? From their specs they use the same turbine as 2530's and GT-RS's but the compressor is an unusual 69mm diametre so may prove a little less laggy than the GT-RS's 71mm compressor depending on wheel trim and housing AR . I have to assume its compressor is a special by Garrett for HKS which they do at times . I'm not sure if its available with housings to suit an RB26 but its food for thought .

Cheers A .

We have GT-RS turbo's and will change back to 2530's if i can't overcome the lagginess (is that a word) of them. Larger capacity seems the only answer.....or a shot of gas off the line to spool them up quicker. mark99 our car is drag only so may be a candidate for your crank upgrade.

Paul...when you say 'lag', do you mean throttle response (as in how long boost take to build when you open the throttle at enough revs for boost) or boost threshold (as in how many RPM are needed to build boost)

I always found the GTRS to be excellent as far as 'lag' goes.

What does your boost curve look like now? With the same cams as you have and a stock engine, I had 1.3 bar at about 4800-4900 RPM. That's not too bad, it's only a couple of hundred RPM worse than 2530s or 2860Rs. That was without any funky cam timing too...was running 110/113 (or whatever PONCAMS run...forget now) lobe centres.

Grab a laptop and head out to the track and play with the spoolup. You should even be able to do it on the freeway as you don't need to be doing ridiculous speeds to tune the spoolup area.

Paul...when you say 'lag', do you mean throttle response (as in how long boost take to build when you open the throttle at enough revs for boost) or boost threshold (as in how many RPM are needed to build boost)

I always found the GTRS to be excellent as far as 'lag' goes.

What does your boost curve look like now? With the same cams as you have and a stock engine, I had 1.3 bar at about 4800-4900 RPM. That's not too bad, it's only a couple of hundred RPM worse than 2530s or 2860Rs. That was without any funky cam timing too...was running 110/113 (or whatever PONCAMS run...forget now) lobe centres.

Grab a laptop and head out to the track and play with the spoolup. You should even be able to do it on the freeway as you don't need to be doing ridiculous speeds to tune the spoolup area.

boost threshold...there is now a 1000rpm hole in my torque curve...ie. similar power and torque as before but 1000rpm later...but in saying that, we made more power but later on in the rev range and still climbing at 9500rpm. I don't want to rev the guts out of it to make the similar numbers as before and the off the line torque of the 2530's is now gone. Dropping it at 8500rpm-9000rpm off the line is bogging the car on launch...instead of 1.4 60' times with instant throttle response and the tyres on the limit of grip.

hey dirt garage any chance of seeing that dyno sheet? also i remember hearing somewere that a rb26/30 at 7000rpm or was it 7500rpm will make the same power as a rb26 will at 9500rpm?

so yer power still climbing at 9500rpm.. maybe more cubes is gunna have to be the option?

  • 1 month later...
  • 3 weeks later...

Sorry in the delay with updates, been absolutely flat out....

I put bigger injectors in and the car ended up making 406rwkw @ 18 pounds on pump fuel. Any more boost and it only picked up small amounts of kw and started to heat the air, not sure if the turbos are maxed out or if something in the induction setup is causing a restriction... not sure if my cooler is big enough. I've got another dyno sheet but its done in shoot 8 insted of shoot 6 so the torque figure is different due to the different ramp rate?? ( i dont know much about dynos). The power curve looks identical, just goes a few kw higher... To drive, the car is nice and broad and controllable in power delivery,pulls well from 3000 rpm and hard from 4500 through to 8500rpm...

Ive two more cranks almost ready to go, and more started for those that are interested. Please PM if you are intersested, so we can discuss options. It can be set up with std rods, or after market, 21mm or 22mm pins. My car will be on display at Adelaide auto salon, as will a 2.9l short engine. As usual any questions, comments or ideas just shoot

Mark

Ahh nice work mark,

what price would someone be looking at for an engine built. would you be able to break down the costs also.

Looking good otherwise! i'd see this as a nice setup for the new large singles that have been comming out recently.

and for those of us that cant fit a 3litre underneath due to not wanting to get rid of the stock bonnet :dry:

Im from Rhemac Motors, we are a performance engine machining shop. Prices for a built engine really would vary, depending on brands of parts used, std rods or aftermarket, how big a cams etc etc. PM me a phone number and i can call you. But ball park, crank and custom CP pistons, pins and rings $4000. By the time you did a whole engine and assembled it, start around $9000 - $10000 depending on what options, and then go from there with yet more options. Ill try take some pics on the weekend and post em up

Guest Mashrock

Thats ok mark, i'm not actually looking at getting this done as i am happy with my setup and i dont have money for engines at the moment. possibly more a future thing.

i understand that there is alot of variation in engine building and final cost would vary alot.

still glad to see this, and hope all goes well.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • Hi, is the HKS  Tower Bar still available ? negotiable ? 🤔
    • From there, it is really just test and assemble. Plug the adapter cables from the unit into the back of the screen, then the other side to the car harness. Don't forget all the other plugs too! Run the cables behind the unit and screw it back into place (4 screws) and you should now have 3 cables to run from the top screen to the android unit. I ran them along the DS of the other AV units in the gap between their backets and the console, and used some corrugated tubing on the sharp edges of the bracket so the wires were safe. Plug the centre console and lower screen in temporarily and turn the car to ACC, the AV should fire up as normal. Hold the back button for 3 sec and Android should appear on the top screen. You need to set the input to Aux for audio (more on that later). I put the unit under the AC duct in the centre console, with the wifi antenna on top of the AC duct near the shifter, the bluetooth antenna on the AC duct under the centre console The GPS unit on top of the DS to AC duct; they all seem to work OK there are are out of the way. Neat cable routing is a pain. For the drive recorder I mounted it near the rear view mirror and run the cable in the headlining, across the a pillar and then down the inside of the a pillar seal to the DS lower dash. From there it goes across and to one USB input for the unit. The second USB input is attached to the ECUtec OBD dongle and the 3rd goes to the USB bulkhead connected I added in the centre console. This is how the centre console looks "tidied" up Note I didn't install the provided speaker, didn't use the 2.5mm IPod in line or the piggyback loom for the Ipod or change any DIP switches; they seem to only be required if you need to use the Ipod input rather than the AUX input. That's it, install done, I'll follow up with a separate post on how the unit works, but in summary it retains all factory functions and inputs (so I still use my phone to the car for calls), reverse still works like factory etc.
    • Place the new daughterboard in the case and mount it using the 3 small black rivets provided, and reconnect the 3 factory ribbon cables to the new board Then, use the 3 piggyback cables from the daughterboard into the factory board on top (there are stand offs in the case to keep them apart. and remember to reconnect the antenna and rear cover fan wires. 1 screw to hold the motherboard in place. Before closing the case, make a hole in the sticker covering a hole in the case and run the cable for the android unit into the plug there. The video forgot this step, so did I, so will you probably. Then redo the 4 screws on back, 2 each top and bottom, 3 each side and put the 2 brackets back on.....all ready to go and not that tricky really.      
    • Onto the android unit. You need to remove the top screen because there is a daughterboard to put inside the case. Each side vent pops out from clips; start at the bottom and carefully remove upwards (use a trim remover tool to avoid breaking anything). Then the lower screen and controls come out, 4 screws, a couple of clips (including 3 flimsy ones at the top) and 3 plugs on the rear. Then the upper screen, 4 screws and a bunch of plugs and she is out. From there, remove the mounting brackets (2 screws each), 4 screws on the rear, 2 screws top and bottom and 3 screws holding in the small plates on each side. When you remove the back cover (tight fit), watch out for the power cable for the fan, I removed it so I could put the back aside. The mainboard is held in by 1 screw in the middle, 1 aerial at the top and 3 ribbon cables. If you've ever done any laptop stuff the ribbon cables are OK to work with, just pop up the retainer and they slide out. If you are not familiar just grab a 12 year old from an iphone factory, they will know how it works The case should now look like this:
    • Switching the console was tricky. First there were 6 screws to remove, and also the little adapter loom and its screws had to come out. Also don't forget to remove the 2 screws holding the central locking receiver. Then there are 4 clips on either side....these were very tight in this case and needed careful persuading with a long flat screw driver....some force required but not enough to break them...this was probably the fiddliest part of the whole job. In my case I needed both the wiring loom and the central locking receiver module to swap across to the new one. That was it for the console, so "assembly is the reverse of disassembly"
×
×
  • Create New...