Gt30 Low Mount Tune Results

[GunMetalR33]

Hi,

As the title suggests I am having a little trouble with my tune on a rb25det with a gt30 bolted on. Mods are as follows:

all supporting fuel mods, pfc Pro, zaust cam gear 3' neg, 3 inch zaust etc etc etc... Oh yea, running 19.5 psi...

The A/F ratios are just below 12:1 but so close you could say 12:1...

after we got the fuel right we started to add timing, but once we hit about 245 kw she started to ping badly, Big Carl had the same setup and made 260 kw... I cant think why I am experiencing this pinging, possible reasons are:

bad fuel?

oil in the intake piping?

F*ck, I dont know

any ideas why I am experiencing this pinging? We did not get a chance to wind much timming into it due to the pinging...

Would it be better to add a little more fuel to allow for more timming?

Edited November 14, 2005 by GunMetalR33

[GunMetalR33]

UPDATE:

Just spoke with my tuner, I was wrong about the A/F Ratio's. They are actually about 11.6:1 which is ritcher than I figured. Also on a power run it seems that the knock is happening at 6,000 rpm at full boost. Had a look at the map trace and I think we are only talking about 3 or so cells of timming that are causing the knock.

If I amend those ignition cells and the knock goes away is it safe to lean it off to say 12:1 and would this make much difference to the power produced? (I am not worried about the final figure on the dyno, I was just expecting more mid range than the tune currently produces).

[Robo's]

Experiment with pulling 1 degree timing out when she starts to ping. Trace with the Map trace or you can do it easy with the settings -1 timing but that will pull one degree out everywhere and you dont want that.

Going from 11.6 to 12.0 is not going to make much difference at the wheels

Good luck

[GunMetalR33]

cheers,

Yea I have taken -1 out of the entire map just to see if 1 deg would make a difference and it did so now I just have to isolate to cells at around 6000 rpm causing the knock and take a degree out or two.

I would expect, leaning it out a little would make some difference...

[rob82]

You sometimes find that a car will not ping on the dyno but will on the road, its just due to the acceleration rates. Dyno dynamics shootout mode acceleration rates are far to fast IMO.

[PHaT MR30]

i thought retarding the exhaust cam gear was more beneficial?

[TTT]

of topic but can I ask what the specs are on the gt30 you used?

0.83 housing?

what hp is it rated at?

bolted to stock rb20 manifold?

cost?

from where?

thanks

[GunMetalR33]

its a standard GT30 comp housing bolted up with a high flowed rb25 zaust housing. Dont know the HP rating as its a bit of a hybrid. bolted to stock rb25 manifold and cost me about $2000 from hp in a box.

[GunMetalR33]

i thought retarding the exhaust cam gear was more beneficial?

<{POST_SNAPBACK}>

It might be retarded, now you have confussed me???? I know that it made a benifical difference when I put it on so I must have it right

Actually now that I think about it, it was neg 3 deg

Edited November 14, 2005 by GunMetalR33

[GunMetalR33]

I am not sure if my tuner set the lag time for my Nismo 555cc injectors, does anyone know what the lag time should be for theses injectors with a rb25det ???

Could this be part of the problem?

Edited November 14, 2005 by GunMetalR33

[paulr33]

are you referring to the lack of midrange problem re: injector lag time wrong? or something else. try a dyno run with the dump pipe / exhaust dropped off. see how the midrange compares. may find the exhaust is too restrictive

[BHDave]

The lag time won't be an issue as you have tuned the car at the current setting.

With a similar setup i found about a 3rwkw loss dropping mixtures from 12.4 to 11.9 with no other changes.

Out of interest, what sort of response does it have? Any dyno sheet?

[BHDave]

Just noticed you are running an rb25 exhaust housing. They are pretty small and may be restricting the flow, but on the up side improved response.

I thought the internal gate gt30 hybrids were using vg exhausts?

[GunMetalR33]

The lag time won't be an issue as you have tuned the car at the current setting.

With a similar setup i found about a 3rwkw loss dropping mixtures from 12.4 to 11.9 with no other changes.

Out of interest, what sort of response does it have? Any dyno sheet?

<{POST_SNAPBACK}>

Arr, so I am not going to get to much power from leaning off then... The response is not bad. I get full boost (19 psi) at about 4000 rpm.

I will post the dyno sheet tomorrow...

Thanks for all the replies, Oh yea: I just changed the ignition cells that were causing the issues and it seems to have solved the knock issue...

Now I just need a little more power.

[PHaT MR30]

hmm what about the wastegate size? may be a bit small and overboost, which wasn't apparent on the dyno?

[GunMetalR33]

hmm what about the wastegate size? may be a bit small and overboost, which wasn't apparent on the dyno?

<{POST_SNAPBACK}>

No over boost is happing cause the PFC tells me the max value for manifold pressure and it never gets higher than about 1.3 bar... Maybe 1.32 but the tune allows for a little over boost...

Edited November 14, 2005 by GunMetalR33

[The Mafia]

I'm running a GT30r with a VG30 exhaust housing, (.63 internally gated) and I will let you know how i go with the tune next week.

I'll have Nismo 550cc injectors.

Also, its bolted up on the stock manifold etc, pretty much the same setup.

I have a powerfc also.

man, 19psi? I that a stock bottom end? If so.. thats gonna kill it!

[Miller the hoon]

Champ i was told yesterday that japan fuel is 102 - 104 ron

try 98ron + octane booster

$20 for a bottle

worth a try

james

[paulr33]

thats a silly fix for the problem. drop the exhaust and i bet you gain some fairly hefty power

[R31Nismoid]

dont use octane booster unless you wanna change your plugs after using it.

If you cant get it working on PULP then there is a problem somewhere.

I'd start with the exhaust side of things.

Drop it and see what happens. You also need to find out the spec/rating of that turbo