Project 'gozila'...

[Marko R1]

Someone was asking about flow figures for Markos head. My laptop on the flowbench shat itself a couple of weeks ago, I have all the figures on a memory stick somewhere here, just need to dig it out. I've attached some figures for a head I just finished this week, similar to Markos but with .5mm o/s valves. Std and modified flow curves are plotted. This head has standard shaped chambers, standard sized port openings, radiused/5 angle seats, a fair amount of bowl and short turn work and the exhaust bump removed. The tests were done with a radiused intake bellmouth the same size as the standard manifold. All readings are at a depression of 28" water.

Markos head was a touch less on the intake, very similar exhaust. It is possible to get much higher cfm readings but it kills air speed. For peak power it would work ok with a much bigger port but what you lose in the low to mid lifts isn't worth it. Increasing the exhaust port opening does pick up about 25cfm but the manifold kills it anyway so I prefer to keep it small and stop reversion. intake/exhaust percentage is up a fair way most of the range until it hits the higher lifts where the exhaust valve size kills it. I just finished an evo9 head before this one and they make an RB26 look fairly average, I'll post up a graph for it if anyone is interested.

greg - what do the different colour lines represent?

[proengines]

Good question, it doesn't make a lot of sense without a legend:

Teal> std exhaust

Red> modified exhaust

Green> std intake

Grey> modified intake

CFM runs up the left y-axis

Red line across the top is test pressure on the right y-axis

x-axis is valve lift. I test at .050" (approx 1.25mm) increments. Std ports are tested up to .400" (10mm), modified ones to .450" (11.25mm) lift.

[N1GTR]

Greg the "modified exhaust", are you meaning cleaned up stock manifolds, opened up exhaust ports or something completely different?

I notice you said the stock manifolds are basically a problem, but for example what sort of difference do you think would be gained by getting some new manifolds - tomei, 6boost etc?

[Marko R1]

Greg the "modified exhaust", are you meaning cleaned up stock manifolds, opened up exhaust ports or something completely different?

I notice you said the stock manifolds are basically a problem, but for example what sort of difference do you think would be gained by getting some new manifolds - tomei, 6boost etc?

greg is referring to stock manifolds which are port matched (not extrude honed) like my setup

[N1GTR]

Reason i ask is that there's a few guys here (including myself) using cleaned up stock manifolds and getting good results, but for me at least its always been in the back of my mind "did i make a mistake with the manifolds?!"

My motor is out quite soon and its a good chance to organise some different manifolds for it

Thanks

[Swiper the Fox]

greg is referring to stock manifolds which are port matched (not extrude honed) like my setup

i dont think you could beat the stock extrude honed manifolds...especially if they are black coated.

[N1GTR]

Well its interesting you say that, as from what im finding out the cost to extrude hone is comparable(ish) to buying a set of 6boosts.

So id like to see results back to back 6boost vs modded stockers

EDIT: UAS is the cheapest so far, which is a suprise

[Marko R1]

i spoke to john @ uas as i was going to buy a pair of extrude honed manifolds, his supplier no longer offers this service due to low profit margin.

i then spoke to another guy (cant remember the details) who is basically the last man standing that offers extrude honing & he wanted $1200 + matching porting!

[Beer Baron]

I would assume modified exhaust he means the exhaust side of the head? not manifolds etc. ie, the flow after the head was 'ported' it would not be done with manifolds attached guys.

[9krpm]

i replotted my 3rd and 4th gear over each other last night and it looks nothing like that...one line is just under the other...ill scan it for you if you like.

Zoom in until your vertical axis is only around 330rwkw and you will see something else

That's one of the reason why one should not compare dyno printout, especially when speed is on the x-axis.

It's a common misunderstanding because of the optical effect on the eyes. The eyes get tricked with the slope of the curve.

It is a lot easier to compare response on a power/torque vs rpm graph.

IMHO, power is just the combination of effective compression and ignition timing for a certain air/fuel mixture.

Effective compression is influenced by static compression, blow by, air density and air pressure.

Therefore for a car to produce high power/boost ratio, one should have

-huge intercooler to increase the air density (i.e. more air per unit of pressure)

-good flowing head, big cams lift

-tight engine with very little blow by

-lots of ignition advance

As you can see a lot of these things are more practical for drag cars rather than cars built to endure high temperature on the circuit.

So it's unfair to compare your drag engine to an engine that is built for the circuit.

However, the RB26/30 engine will always have more response than a well built race RB26.

There is simply no replacement for the extra 400cc displacement

[proengines]

Beer Baron, you're right. That's the ports before and after porting. The intake port is the same size and shape opening at the manifold face as standard. I use a perspex radius plate on the intake to flow them, nothing on the exhaust though I should make up a stub pipe. The exhaust port is close to original size at the opening with the bump removed, most of the work is in the bowl area, short turns and some work on the port dividers. It's going on an RB30 as well, 280 Camtech cams in it.

[Marko R1]

greg, what is your customers power goal and do u know the turbo setup?

[Swiper the Fox]

Zoom in until your vertical axis is only around 330rwkw and you will see something else

That's one of the reason why one should not compare dyno printout, especially when speed is on the x-axis.

It's a common misunderstanding because of the optical effect on the eyes. The eyes get tricked with the slope of the curve.

It is a lot easier to compare response on a power/torque vs rpm graph.

IMHO, power is just the combination of effective compression and ignition timing for a certain air/fuel mixture.

Effective compression is influenced by static compression, blow by, air density and air pressure.

Therefore for a car to produce high power/boost ratio, one should have

-huge intercooler to increase the air density (i.e. more air per unit of pressure)

-good flowing head, big cams lift

-tight engine with very little blow by

-lots of ignition advance

As you can see a lot of these things are more practical for drag cars rather than cars built to endure high temperature on the circuit.

So it's unfair to compare your drag engine to an engine that is built for the circuit.

However, the RB26/30 engine will always have more response than a well built race RB26.

There is simply no replacement for the extra 400cc displacement

Drag engine....your kidding right? Guys who have tuned this car have noted and even said "this is the coolest RB engine ive ever seen" you could tune the car from go to wo and not even worry about the temp...it simply doesn't get hot and that was without the 21 row earls oil cooler with thermoblock which was removed from the car. That engine combo would outpunch most circuit RB's you would care to name. The cooling channel mods to the head and all the header tanks and big radiator etc ensured the engine was an all-rounder...Contrary to popular belief a big flowing head with big cams actually brings the torque on earlier and hold it on for longer...ill dig up a graph to show you how rediculous the torque curve was with the RS's before we did the head. We didn't run mega ignition advance as Jim understood the budget and ensured the engine was tuned so i could flog the thing all day without a worry...it had 5 degree's less advance than your street tune actually (the Martin Donnon pump fuel tune one). That engine was not a drag engine...it was much better than that thanks mate. No block filling etc was used also.

The car was built as a tough GTR...we just happen to drag race it...its very annoying when ill directed comments like your post above are made when you have no idea what went into building the thing.

The car is only now starting to become a drag car but will still use a long engine thats not really built for the job. Once i get the RB30 built then it will become less of an all rounder as ill be filling the block with Hardblock.

your post was way off the mark...sorry.

Edited July 23, 2009 by DiRTgarage

[9krpm]

I think your information is a bit misleading there Paul.

I respect the forum's rules and I won't mention any name(s). I hate to get drag into these workshop bittering debate but I do feel that your remark needs some clarifications for the person's name you mentioned.

Effective timing advance with the RB is what is in the ECU and where the CAS is at.

I've heard comments similar to your about the timing BS before from a tuner who regularly claims that his tune has less timing than others and make more power.

After paying for 10+ hours of his tuning, the car felt not as responsive in the midrange and couldnt even make any more power up top with the same amount of boost and e85 compare to the street tune for E10 fuel that you mentioned.

Yes the tune had, from memory, roughly 5 degrees less timing or something around there in the ECU. Yes you read correct, less timing with E85 fuel. However when I had my timing gun on the car at idle I found the engine and ecu was out of sync. The engine has 2-3 degrees extra timing on top of the ecu.

Myth busted ???

The street tune you mentioned is my only tune for the car. The car has been to Mallalla, Queensland Raceway and Lakeside tracks many times in the past 2 to 3 years since I bought the OS engine from Willall Racing. Engine was built with slightly larger clearance for circuit. Engine has never miss a beat with that tune.

My previous RB26 engine also had a tune from the person you mentioned. It did not miss a beat for the 2 years that I had it on the tracks also. It is still sitting on an engine stand as my spare atm. The ecu was power fc d-jetro.

The reason I wanted to test the vipec ecu is because I wanted to try out a new E85 fuel. The fuel is still new so I just want an ecu with the knock control function, just in case of bad fuel supply.

your post was way off the mark...sorry.

I am not sure where I am off,

IMHO;

-large intercooler helps lower intake air pressure (boost),

-good head porting work + big cams lift helps flow, reduce intake side restriction and lower intake air pressure (abit the stock head flows well with Force induction anyway)

-high static compression, tight ring clearance with little blowby, all helps to achieve a higher effective compression

If you think I am way off the mark, take your car with the drag size intercooler to the circuit and do a few laps and see how well it copes with the heat.

BTW my oil temp on my current setup never read higher than 105 C on the circuit and none of the tuners I've been to say "this is the coolest RB engine Ive ever seen" . Is this some sort of drag racer's "RB record" ?

Edited July 23, 2009 by 9krpm

[r33_racer]

We struggle to get the oil in our car to higher then 70 degrees on the circuit.... Cant get water temp higher then 80 degrees. The only time it gets upto a good operating temp is when we come into the pits and the heatsoak starts bringing everything upto where i want it....Those temps are about 10-15 degrees higher in summer....everytoher time of the year its like the mentioned figures or worse...especially in winter. Last sat practice session, i couldnt get oil or water temp to get off the bottom of the gauge.

What do you guys classify as not getting hot? or what do most tuners classify as not getting hot?

[Marko R1]

...Contrary to popular belief a big flowing head with big cams actually brings the torque on earlier and hold it on for longer...ill dig up a graph to show you how rediculous the torque curve was with the RS's before we did the head.

ive heard this about big cams from 2 other well respected workshops. i have a graph of my RS's on stock head with rb26, best way to describe is its like an oversized 2 stroke

Once i get the RB30 built then it will become less of an all rounder

your rb30 will carry heavier pallets than mine lol

[Marko R1]

on another note, Dirtgarages engine is far superior to my engine which paul himself highlighted prior to posting his graph as a heads up

as crd mentioned to me, paul has a 10k head, aftermarket intake plenum, single throttle, bigger cams and exhaust, modded turbos (not sure about this 1 though) etc...i hope ive put the fire out guys

if my info is not accurate im sure paul will set the record

[9krpm]

That engine combo would outpunch most circuit RB's you would care to name.

on another note, Dirtgarages engine is far superior to my engine which paul himself highlighted prior to posting his graph as a heads up

as crd mentioned to me, paul has a 10k head, aftermarket intake plenum, single throttle, bigger cams and exhaust, modded turbos (not sure about this 1 though) etc...i hope ive put the fire out guys

if my info is not accurate im sure paul will set the record

Yes I am out as well.

My engine is just some Jap parts assembled together.

It only did a few 8's passes for the quarter in Willall Racing drag car before I bought, freshened and installed it into my circuit car.

It's nothing like Dirtgarage's engine that had <insert big names> workshops' tender and loving care.

I have not taken it to the quarter because I have nothing to prove, don't intend to beat it's 8 sec record with my low mount turbo and I enjoy the corners more. I may take it to the sticky strip one day when I have time because I do enjoy that too.

Would I care to name some circuit RB?

I would but this is not the place to do it......Oh wait there was a thread on here about it aldready

Please excuse the repost

http://www.skylinesaustralia.com/forums/Wo...tml&hl=drag

and I know it's not any lighter than twoggle so I don't want to hear that excuse again.

If it makes the shirtman happy he wins

I am sorry to go off topic like this but I cant understand the attitude of my RB26 is better than RB30, then I am building a RB30 to replace the great rb26 and pull my tuner's name out to have a go at as well.

Not cool.

Sorry to mess up your nice thread Marko.

[Marko R1]

did u buy the donk from keir wilsons gtr (os30)?

that aust delivered silver gtr is my wet dream - ive read so much about the progress of his car over the years which was part of the reason why i bought my 1st gtr 6yrs ago

the last time i read it was making over 600awkw? is it still running the hks 3037 high mount kit with the funky hks cam cover colour scheme?

[9krpm]

Marko, I bougth the donk from the drag car.

The street car you mention is still well alive. I agree that it is one of the best Aus delivered R32 I had the pleasure of test driving. Thanks to the great man