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#466
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Re: Individual Throttle Bodies and Improved Airflow
Yes Matt that is the missing link.
The whole collection of bits has to all be pointed at trapping the most air in the cylinder when the inlet valve closes, and expanding that air to the highest pressure. The cam duration says, when the inlet valve is closing, and the inlet tract resonance says, when the highest negative pressure is generated in the cylinder. They must both be at the same rpm, to achieve the objective. With the standard engine the 240* duration and the resonate length of the inlet tract, and exhaust, all hit the spot at 4800 rpm. We have to achieve the same duration/resonate match at higher rpms, to produce more power. Harvey.
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One Arm Bloke. Tell it like it is! 95 Lsi. Bordeaux Pearl, Aust. RHD.149,000Kls Subaru BBS wheels. 97 Liberty GX Auto sedan. 320,000Kls. 04 Liberty 30R Auto Premium. 92.000kls. |
#467
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Re: Individual Throttle Bodies and Improved Airflow
Good morning,
How do you think the IRIS valve affects a force fed engine? The physics are the same, but there's always a positive pressure in the inlet (uder boost)..... I think the shape of the original torque curve can be seen in the last g-value plot in my MPT capacity thread..... the front wheels are on the edge of loosing traction at BOTH torque peaks My turbo is a rather old T3/T4 hybrid, with a 0.82 A/R turbine case, a T04B compressor case and a trim 54 compressor wheel.... it holds boost nicely all the way to the forced shift points, but the torque runs flat on its face after 5500 rpm..... so, the turbine side shouldn't induce too high exhaust pressure on a 3.3 engine and the compressor map suggest it can support the air flow.... Any insight on selecting cams on turbo engines? I will do a dyno run tonight and post the results tomorrow. Let's see how they correlate with the race tech g-value measurement Regards, Tapani |
#468
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Re: Individual Throttle Bodies and Improved Airflow
Tapani[/QUOTE]
[QUOTE=Tapani;690603]Good morning, Quote:
My turbo is a rather old T3/T4 hybrid, with a 0.82 A/R turbine case, a T04B compressor case and a trim 54 compressor wheel.... it holds boost nicely all the way to the forced shift points, but the torque runs flat on its face after 5500 rpm..... so, the turbine side shouldn't induce too high exhaust pressure on a 3.3 engine and the compressor map suggest it can support the air flow.... Quote:
It will still exhibit the same power curve as the standard engine as the engines tune is the same. Maximum torque and power will still occur at the same rpm as standard. A higher lift inlet cam, same timing, will help the top end, but will reduce the inlet velocity, that may hurt combustion at the lower end rpms. I will do a dyno run tonight and post the results tomorrow. Let's see how they correlate with the race tech g-value measurement Regards,
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One Arm Bloke. Tell it like it is! 95 Lsi. Bordeaux Pearl, Aust. RHD.149,000Kls Subaru BBS wheels. 97 Liberty GX Auto sedan. 320,000Kls. 04 Liberty 30R Auto Premium. 92.000kls. |
#469
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Re: Individual Throttle Bodies and Improved Airflow
Ok, a night at the dyno...
Really hard time to get enough traction..... warmed the tires for ages - then they applied some kind of spray that did the trick in third...... no chances in second. The dyno is old, but calibrated - no engine speed data, though. The hp peak is at 136 km/h in third - this equals to approximately 5500-5700 rpm with 4.444 gearing. The loss for the dyno (and tires) is measured during coast down in neutral. Without compensating for this I got 184whp. Adding up the dyno + tire loss resulted in 233whp. All tires sit fairly deep between two drums.... very different from road losses.... All this @ 5PSI boost level, holds nicely all the way. AFR was actually closer 13 than 12..... not really lean, but could be a bit lower..... I think. The temperature inside the wheel well (intake) was 31 C and pressure 1013 mbar. The 150-160-170whp levels presented for stock engines - are these including the dyno losses or without them? How should we estimate the losses for the slushbox + rest of the drive train? Tapani |
#470
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Re: Individual Throttle Bodies and Improved Airflow
Quote:
Jack's car made 210hp/212 torque with an all-standard engine except for: *Autronic ECU *Autronic CDI ignition *1.75" headers (32" long) into 2.25" secondary tubes into one 3" main exhaust tube. *cold air box @ Impreza hood scoop (fwiw, this was worth 38 hp on the final spec engine!) The transmission used was a 5-speed 2.5 RS gearbox, the final drive was 4.11. Tires back then were 225/50-16 Falken RT-615's. This was on a Dynapack chassis dyno, as was the 'middle-spec' hp number of 292 hp. The final spec (3.5 litre high compression) was dynoed on a Mustang chassis dyno. Even though that has been highly touted as 318 whp, it actually made 352 whp in it's final specification. The reason for not disclosing the true number is due to the NASA rules...the power-to-weight ratio had been surpassed, putting the car into the next race group. Last edited by RallyBob; 11-09-2011 at 07:32 PM. |
#471
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Re: Individual Throttle Bodies and Improved Airflow
Hi Matt did you retune the ECU with a new fuel map?
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1995 - SVX 700,000 K Mine, DMS Struts to lift car 2in. Tyres Wrangler Silent Armor 235/70R16, PBR Radiator. 6 speed with DCCD and R180 rer diff, Heavy duty top strut mounts front and rear. Speedo correction box fitted. New stero (gave up on the old one). Back seat removed and 2 spare tyres fitted for desert driving. ECUTune SC sitting in the box for the next SVX. 1992 - SVX 255 K Wife (Want to stay Married so not allowed to fit SC) 1992 - SVX Pearl with black roof race car roll cauge etc ready to race. Ex Tasman Targa car. 1995 - SVX Green low k mint condiation. 1995 - SVX Rally car, ex Matts car. Now to be used on track. 1992 - SVX red & Black being converted to Mid Engine. 1995 - SVX Red 143,000 bit rough. Owned 5 others Subaru back to a 1974 1400 GSR. |
#472
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Re: Individual Throttle Bodies and Improved Airflow
Hi Tony, yes I was on the dyno to do some tuning of the load maps I couldn't (safely) hit on the road.
Thanks Bob, yes that was my recollection. However, I am now wondering whether there's some northern hemisphere inflation going on? |
#473
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Re: Individual Throttle Bodies and Improved Airflow
Quote:
Harvey.
__________________
One Arm Bloke. Tell it like it is! 95 Lsi. Bordeaux Pearl, Aust. RHD.149,000Kls Subaru BBS wheels. 97 Liberty GX Auto sedan. 320,000Kls. 04 Liberty 30R Auto Premium. 92.000kls. |
#474
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Re: Individual Throttle Bodies and Improved Airflow
Quote:
On the Mustang dyno, the same 300 'crank' hp STI reads about 230-235 whp. But they have large rollers and the wheels and tires stay on the car. It was on the Mustang dyno that Jack's EG33 hit the highest numbers. |
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