Confusing Dyno Result..r34 Gtt

[gts4-skyline]

Well, after fitting a 3"dump and front pipe, and turning the boost up to 12 psi I have lost 12 rwkw.

It has an electronic boost controller and SAFC II, which was tuned a couple of weeks ago without the Dump pipe and achieved 208 rwkw on about 10psi. After fitting the dump pipe the graphs look alot smoother, but where would the power dissapear to and should I spend another $300 to get the SAFC tuned again?

Edited October 9, 2005 by gts4-skyline

[The Mafia]

can anyone say "BOOST CUT"

lol

Engine does the richen and retard strategy at 12psi or above.

wind your boost back to 10 or 11, or get a full replacement ECU, and you'll be laughing.

Edited October 9, 2005 by The Mafia

[BHDave]

You may be pushing further into the rich/retard section of the map by improving the exhaust flow and increasing the boost.

Your initial run of 208 seems to me to be inflated (particularly as you still had only 10psi and stock front pipe). Your second run with the front pipe on seems to be on the money as far as power for your mods.

As there is no air fuel ratio shown i cant say whether your safc needs retuning. $300 bucks for a tune only is a rort. Some one is having a lend of you as it should take all of half an hour to do a complete retune on an safc.

[gts4-skyline]

There was no boost cut as far as I could hear, also one of the runs on the second chart was at 11psi. After reading one of the threads on here I thought it could have been a boost issue, but it only ran slightly less.

The inflated figure on the first chart could be due to it being a hub dyno, which usually gives a higher reading due to no loss through the tyres and wheelspin on the rollers.

[R31Nismoid]

retune - SAFC = cheap

a full PowerFC tune is like 500-600! and thats drop the car off and get it in 2-3 days time.

300 is madness for retune

[pommey barstard]

mate your tuners sound like rip off merchants . I got a power fc fitted and mapped and a front trust downpipe fitted in an afternoon but i am the otherside of the world. i've just done a conversion and it would of cost $3050.00

[Sydneykid]

There is no such thing as "BOOST CUT", the standard ECU has Rich & Retard (R&R) mapping for excessive airflow as measured by the AFM. Boost is IRRELEVANT, I have seen heavy R&R mapping at 9 psi and the R34 generation of ECU (as used in R34GTT and Stagea) has very aggessive R&R strategy.

You have removed some restrictions with the dump and exhaust upgrade. Removing restrictions means that the airflow is higher even at the same boost level. Always keep in mind that boost is simply a measure of the resistance to airflow, NOT a measure of the airflow itself.

Moving onto your specific problem, actually I suspect that you have 2 problems. The first (the major one) is the additional airflow has moved the ECU deeper into R&R mapping, this means more correction is needed via the SAFC. Secondly, at 12 psi you may be getting to the limit of temperature control as the efficiency of the standard turbo drops off at airflow over 30 lbs of per minute. If you have decent intercooler and good ambient airflow this may not be a problem, but it will be close.

The cost of retuning the SAFC should be around $100 as it will take less than 1 hour, most of which will be spent plugging the car into the Dynapack.

Hope that was of some help

cheers:)

[gts4-skyline]

Thanks for that, do you think a retune would fix the problem, and atleast get me back to the 208kw mark, maybe even higher. Another option would be to hopefully jump onto the Power FC group buy and get one of those. Which means later down the track if I feel the need for more power the ecu is already there. What is involved in fitting on of these, I assume you can use what the SAFC was pluged into plus some more wires?

Thanks for you input Sydneykid, much appreciated

[gts4-skyline]

anybody else have any ideas?

[Sweetleaf]

Did they have to add much fuel with the SAFC because if you add fuel you are telling the ECU its under higher load adding more fuel but also retarding the ignition leaning out does the opposite, This is why only minor changes should be done with an SAFC ,anything major its time for a full management system.

[gts4-skyline]

I think they took fuel out, I'm not totaly sure. When I first installed it and we did a road tune we took fuel out, but not sure what happeded on the dyno tune because I wasn't there, and I didn't ask

[Sydneykid]

Thanks for that, do you think a retune would fix the problem, and atleast get me back to the 208kw mark, maybe even higher. Another option would be to hopefully jump onto the Power FC group buy and get one of those. Which means later down the track if I feel the need for more power the ecu is already there. What is involved in fitting on of these, I assume you can use what the SAFC was pluged into plus some more wires?

Thanks for you input Sydneykid, much appreciated

<{POST_SNAPBACK}>

A quick tune with the SAFC will fix the R&R problem, shouldn't take more than 1/2 hour and cost less than $100. Since you have higher airflow you should have more power. You need to take a little more interest in what your tuner is doing, that way you can help him achieve a better result.

Tuning with an AFM voltage bender, like an SAFC, has compromises. To lean out the A/F ratio (and get away from the R&R mapping) your tuner will reduce the AFM voltage seen by the ECU by using the SAFC. But (there is always a but) this also advances the igntiion timing, that is the compromise. So your tuner will have to balance out the leanness needed to get good A/F ratios and the preignition caused by the advanced igntiion timing.

The SAFC is a piggy back, the standard ECU is still there. The Power FC ( FC = Full Computer) replaces the standard ECU, just unplug the standard ECU and plug in the PFC. Takes about 5 minutes, most of which is spent removing the trim that covers the ECU. The PFC comes with the basic mapping necessary to starrt the car and it to the dyno for a fine tune. You haven't a lot of mods, so the PFC will have no problems, just don't rev the beegeesus out it until you get it fine tuned.

The Power FC (being a replacement ECU) doesn't have any compromises, for example your tuner can change the A?F ratios without afffecting the ignition timing.

Hope that was of some more help

cheers

[gts4-skyline]

Thanks Sydneykid. I have spoken to another tuner about this and reckons about $200, the dyno owner charges a setup fee(approx$60) plus about $80 per hour for the dyno, plus the tuners time.

I'm in 2 minds as to get a power fc or not, apparently to tune one can be fairly costly because it takes a while using the hand controller and I'm not sure I want to go any further with modifications. What sort of power can the r34 engines handle? because I have heard that because of the compression they run anything over about 230-240rwkw is a bit dicey. There's alot of conflicking advice out there.

Sorry about all the questions, but you seem to be up with the play. As apposed to alot of the opinionated guys on SDU :-)

[Sydneykid]

Thanks Sydneykid. I have spoken to another tuner about this and reckons about $200, the dyno owner charges a setup fee(approx$60) plus about $80 per hour for the dyno, plus the tuners time.

I'm in 2 minds as to get a power fc or not, apparently to tune one can be fairly costly because it takes a while using the hand controller and I'm not sure I want to go any further with modifications. What sort of power can the r34 engines handle? because I have heard that because of the compression they run anything over about 230-240rwkw is a bit dicey. There's alot of conflicking advice out there.

Sorry about all the questions, but you seem to be up with the play. As apposed to alot of the opinionated guys on SDU :-)

<{POST_SNAPBACK}>

We have an R34GTT than makes 265 rwkw, has done for over 2 years with more power EVERYWHERE than standard using a GCG ball bearing high flow of the standard R34GTT turbo. No internal work, I did pull the head off for some porting, just to prove how effective that was. We have done a couple of other R34GTT's with similar results. Ian has an R33GTST (RB25DET non Neo) with 275 rwkw using the same turbine. That's about the limit, in my opinion, for standard RB25DET internals.

cheers

PS, tuning the PFC is so simple, most of the hard work is done by Apexi, the base maps are all loaded. All that is needed is some fine tuning. Even with the hand controller you are not looking at a lot of time. Most good PFC tuners these days have Datalogit anyway.

[benl1981]

I know this may have been covered b4 but what is a quick list of things you need to do to get 250rwkw out of R33/34

PFC

front mount

3" zorst

GCG high flow

injectors

Z32 AFM

exhaust cam gear

Is that it?

[gts4-skyline]

Unfortunatly we dont have a great deal of tuners, only 2 that do this sort of stuff, and they don't have the datalogit, infact I think the car owners usually buy it to save money on tuning time. Would the datalogit be different from the R34 GTT and R34 GTR?