Hks 2.8l Stroker Kit (in Rb26)

[SLY33]

holy crap, those things come on like a lightswitch. Anyone know how to convert those km/h's to revs on the graph!?

[R31Nismoid]

I didnt realise that jagr33 had changed to gt2560r. I might have to send him a line to see what he thinks of them compared to the trust units.

pete

His car isnt done yet i dont think... its very close though, i saw him sat and he was getting it from somewhere or whatever

Pete...what sort of RPM were you seeing max torque with the 2560Rs?

Depends what spec though remember, there are i think 4 different ones depending on what you get.

I forget the numbers, although i saw them in a thread a few weeks ago, just cant remember which (of the 400 ive probably seen)

[pnblight]

GT2560R 707-160-5 IS THE TURBOS JAGR33 GOT SAME AS MINE

0.60AR COMPRESSOR

0.64AR EXHAUST

[markr34gtr]

that was rwhp in my r34gtr....

we ran the same engine and gt rs turbos in my r32 race car with motec and made 550hp at all 4 at 27psi.....

the gt rs turbos hit very hard and hold the power for a long time...

the only down side is you need balance pipe exhaust manifolds to help with the low boost compressor surge..

would have been nice to run 32 psi with my 4 inch exhaust and 50 mm thicker intercooler...i would say come close to 600 at all 4 wheels no worries... or 630 to 650 rwhp...

if you dont mind a bit of low boost turbo shuffle there are not many low mounts that will make that power...

cheers...hope this helps and not start a turbo shit fight....

A dyno graph from a post last year.  This was on an R34 GTR with GT-RS terbs at a high 30 psi of boost.  Standard displacement RB26 but with high lift cams (greater than 11mm) and long duration (272 or more) from memory.

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[Gav]

Hi Mark and thanks for the feedback - I hope you don't mind me posting you graph without permission!

I went with the bridged manifold on your advice and am running a 136mm thick Apexi intercooler, so I would be stoked if I could get anywhere near the power that you predict these terbs are capable of.

Agree - I don't want to start an agruement over how good or otherwise these terbs are - they are what I have and I'll give them the best shot I can of delivering the "goods".

[Sydneykid]

An interesting thread.........a few extra things to think about;

A fast car is a combination of all of its components, the engine on its own is not very fast at all. So when choosing the engine componets you MUST keep in mind the drive line. For example, it is pretty stupid to have an 11,500 rpm engine with standard gearbox and diff ratios. You will end up driving around in 3rd gear all the time and you won't get much out of 2nd over the 1/4. On the circuit, the top speed will be aerodynamically unreachable.

So, make sure you consider the impact of the engine's rpm range on what you are going to use the car for and then select gearbox and diff ratios and tyre sizes to match. The whole package is what makes one car perform in line with its dyno power and another car (with the same dyno power) fail dismally and not achieve anywhere near its potential.

You should also keep in mind the effect of the power band on the clutch. Launching an engine that requires 7,000 rpm to spool up the turbos requires a lot different clutch combination than an engine that launches at 4,500 rpm. The level of clutch control required is also quite different and should not be overlooked.

The top end components required for an 11,500 rpm 800 bhp engine are very different to those required for an 8,500 rpm 800 bhp engine. Valves, valve springs, retainers, collets, buckets and even shims are all living in a very different environment.

Don't overlook the necessary changes in the water pump, oil pump, alternator, power steering pump and airconditioning compressor to accommodate the higher rpm.

Add it all up and you will be surprised how much more an 11,500 rpm 800 bhp car costs compared to an 8,500 rpm 800 bhp car.

cheers

[SLY33]

what rpms is the above graph going to?

Gary,

I wouldnt plan on going past 9 maybe 9.5krpm, that shouldnt require the changes to air con compressor, powersteering etc would it? Do you see the GTRS's giving away more overall than their top end gain is worth?

This low boost surge mentioned, this is due to the engine not being able to swallow the air being supplied correct? Would the increase in capacity to 2.8litre eliminate this?

At this stage the GTRS's are still on the list. But to play it safe i might end up sticking with a new pair of 2530's. Anyone know where i can get new ones? greenline cant get them anymore, nengun still waiting a reply.

Edited October 27, 2005 by SLY33

[Sydneykid]

1. what rpms is the above graph going to?

Gary,

2. I wouldnt plan on going past 9 maybe 9.5krpm, that shouldnt require the changes to air con compressor, powersteering etc would it?

3.  Do you see the GTRS's giving away more overall than their top end gain is worth?

4. This low boost surge mentioned, this is due to the engine not being able to swallow the air being supplied correct? Would the increase in capacity to 2.8litre eliminate this?

5. At this stage the GTRS's are still on the list.  But to play it safe i might end up sticking with a new pair of 2530's.  Anyone know where i can get new ones? greenline cant get them anymore, nengun still waiting a reply.

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1. Divide by 29, that's 4.1 diff ratio with 245/45/17 tyres.

2. We have had this discussion previously. Why would you pay for an 11,000 rpm crank and only use 9,000 rpm? The standard crank will do 9,000 rpm, it's a waste of money buying something that you aren't going to use. I don't see 9,000 rpm as being a problem for the standard pulleys, however 9,500 rpm will require changes, particularly the alternator (easy) and the air con compressor (very difficult).

3. They have had some success in the UK with GTRS's on 2.8 litres with around 9 to 1 compression ratio. The trick seems to be to remove the restrictions so you don't have to run high boost to make the power. Then you can use a more responsive compression ratio.

4. Catch 22, the 2.8 litres swallows more air, but it produces more exhaust. The gain is in removing restrictons not increased capacity.

5. I may have misread it, but I am sure I saw a 2530 new version (Kai) at an aftermarket show in the US. Why don't you just use your current 2530's and see how they go?

Some extra info;

Last time I checked Harrop Engineering made HKS's RB crankhafts and the HKS conrods were made by Carrillo. Apexi turbos are made by IHI, they used to use someone else, but that was many years ago.

cheers

[StageZilla]

so what mods are needed to the power steering, air con and alternator? bigger pulleys i suppose to slow em down? any issues when doing low rpm then? any info appreciated

what about the stock harmonic balancer ? suitable? crank pulley?

this is for a 11000rpm redline

cheers

Brad

[Sydneykid]

so what mods are needed to the power steering, air con and alternator? bigger pulleys i suppose to slow em down? any issues when doing low rpm then? any info appreciated

what about the stock harmonic balancer ? suitable? crank pulley?

this is for a 11000rpm redline

cheers

Brad

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Hi Brad, you can buy off the shelf pulley kits for RB26's to slow down the alternator, power steering and water pump. If you use the larger pulley on an N1 water pump they have difficulty at high ambient temps in traffic, they simply don't move enough water. Keep your eye out for that problem, if it occurs use a standard water pump or a standard pulley.

You will need an 11,000 rpm capable harmonic balancer, I wouldn't be using a standard RB26 one, that's for sure. I thought that HKS made one for their 2.7/2.8 litre kits.

The air conditioning compressor is a difficult one, no off the shelf (larger) pulley that I have seen for them. I found a larger diameter pulley/clutch for a guy a few years back, he had done the SOHC to DOHC swap and killed 3 compressors with the higher rpm. I popped around to a guy I knew that rebuilt compressors and we went though his stock until we found one that was larger in diameter and fitted up to the compressor shaft. We had no idea what car it was off, it fitted, that's all we were worried about. You may have to do the same.

You could always turn off the aircon whenever you are going to give it a rev, but one day you will forget and exploding compressors make a great deal noise, smoke and oily mess. I do know another guy who has an rpm sensitive switch that turns off his air conditioning over 7,000 rpm to avoid that problem. Jaycar have a kit that will do that for you.

Hope that helps

cheers

Edited October 27, 2005 by Sydneykid

[Gav]

You could always turn off the aircon whenever you are going to give it a rev, but one day you will forget and exploding compressors make a great deal noise, smoke and oily mess.  I do know another guy who has an rpm sensitive switch that turns off his air conditioning over 7,000 rpm to avoid that problem.  Jaycar have a kit that will do that for you.

Hope that helps

cheers

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Great idea on the RPM switch!

Another option might be to use the TPS also as many small factory cars do just this. They assume that when you have your foot flat that you want maximum power (funny that - eh?).

[SLY33]

gav, hows the build coming along!?!

[djhatton]

is there a difference in the actual cranks themselves in hks sI II or III? or is it more a case of step 1 - crank only, step 2 - crank and pistons, step 3 - crank rods and pistons

cheers!

david

Edited November 3, 2005 by djhatton

[SLY33]

depending on where you buy the kit from rods may/may not be included in certain kits.

i think from what ive read step 1 and 2 uses forged cranks, step 3 is a billet crank. step 2 and 3 use nickel/molybdenum coating on the pistons. I think rods are same in all kits.

thats as far as i know.

[pnblight]

hks do two types of rods 21mm pins and 22mm pins

[Gav]

gav, hows the build coming along!?!

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Slowly and from afar

Actually, should be in a position to start the run in later this month and then spin some rollers in anger in December.

I have no intention of short circuiting the run-in procedure, however.

[Sydneykid]

Slowly and from afar

Actually, should be in a position to start the run in later this month and then spin some rollers in anger in December. 

I have no intention of short circuiting the run-in procedure, however.

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Hi Gav, I run the race car engines in and then tune them in one day. I leave home early (around 5.00 am) and drive to Bathurst. Lots of variable conditions, long hills, some freeway running, short steep climbs, descents on overrun, etc etc. Have breakfast (around 7.30am) and then drive it back to the workshop (around 11.00 am) with the same mixed conditions, plus a bit of traffic. You can feel how much better it is coming up Mt Victoria and how well it cruises on the freeway on the way home, compared to how tight it was on the way there.

Let it cool down till after lunch and then do a leak down test. If it's OK, drop the Castrol GTX (mineral) and the oil filter and check them out for contaminents. If OK, fill it up with Castrol Formula R (Synthetic) and a new oil filter. Then stick it on the dyno (around 2.00pm) and tune it for power. Home by 4.30 pm.

This driving the car around for months and thousands of k's running it in is rubbish. If it isn't run in after that sort of a drive, it was not built to the corrrect tolerances and most likely never will run in properly.

My tip is to get on with it, don't doddle around for months expecting a better result, you don't actually achieve anythng, other than frustration.

cheers

PS; yes, I always do at least one lap while I am at The Mountain.

[Fitzpatrick Speed Works]

I am with SK you run a car in within the first 200k's, and if you do that right ie varied conditions, high load low revs bit of strapping then you have done it right!!! Some people like my old man dont even believe in a run in, the work out medium load on the dyno then straight into power runs, i guess it works cause hasnt blown an engine, but I feel SK's kind of method is the best!!

[Gav]

Thanks guys - again appreciate the input and advice.

Cheers

Gav

[pnblight]

Thanks guys - again appreciate the input and advice.

Cheers

Gav

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when you back gav