Correlation between max RPM and exhaust mods?

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Correlation between max RPM and exhaust mods.

Hello, is this documented somewhere?


9000rpm Standard exhaust + standard catalytic converter

9100rpm replace standard cat with sports cat

9200rpm replace standard exhaust with sports exhaust

9300rpm replace sports with semi racing

9400rpm replace semi racing with full titanium racing exhaust.


I only noticed this tonight and it was very unexcepted, can someone share some light on this? Similar results with the standard and sports ECU installed but obviously adjusted.
 
It makes sense. Better airflow -More RPM - Better exhaust - Again better airflow and better temperature management, meaning more hot air flow meaning higher rpm.
 
Why would this increase the RPM limit which is set by the ECU. Please note this wasn't a race car. Seems like a goof to me.
 
maybe it sets it automatically because we cant set the RPM limit ourselves like you would be able to in reality with racing chips. (electronically controlled engines)
 
I was actually just thinking about this today.....one thing I think PD could add to tuning would being able to go into the ECU and set the exact amount of power at diffrent RPMs. Need For Speed Underground had that feature along with being able to tune the turbo and mess with the powerband.
 
hypnotron
I was actually just thinking about this today.....one thing I think PD could add to tuning would being able to go into the ECU and set the exact amount of power at diffrent RPMs. Need For Speed Underground had that feature along with being able to tune the turbo and mess with the powerband.
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That was a great and underestimated feature of the game. I'm 100% sure NFSU2 is comparable, if better, regarding the amount of tunning settings than GT5, sadly the game physics meant you barely felt the changes. I specially remember those powerband adjustments, tinkering with the ECU, adjusting my turbocharger for the desired RPM range, looking my car at the dyno...GOSH NFSU2 was cool!!! :lol:.
 
hmmph, that's interesting. I always had it in my head that the N/A engine tuning was what allowed the motor to rev higher... perhaps because that's the way it works IRL ;)
 
ChrisGT
hmmph, that's interesting. I always had it in my head that the N/A engine tuning was what allowed the motor to rev higher... perhaps because that's the way it works IRL ;)
Click to expand...

It does, ecu,exhaust and N/A engine tuning all increase the rpm limit.
 
CarBastard
That was a great and underestimated feature of the game. I'm 100% sure NFSU2 is comparable, if better, regarding the amount of tunning settings than GT5, sadly the game physics meant you barely felt the changes. I specially remember those powerband adjustments, tinkering with the ECU, adjusting my turbocharger for the desired RPM range, looking my car at the dyno...GOSH NFSU2 was cool!!! :lol:.
Click to expand...


Hell yeah, the tuning aspect of NFSU2 was amazing and deep. I would stay up for days just tuning my car till I squeezed out all the power I could get and just destroy anybody who played me. If PD would add just the Dyno Test alone to GT, it would be a major step closer to being a complete simulator.
 
If this is true that's pretty lame. You increase RPM by modifying the internals of the engine, not bolting on an exhaust or a different flywheel. Those mods might make it spin to the limiter faster but without mods to the internals like better springs, lighter rods and pistons, balanced crank and cams, better bearings, etc, you could never spin more RPM safely. Not to say you couldn't do it, my Honda Integra Type R K20 engine I had in my CRX HF was limited at 9900rpm but then again I knew the engine wasn't going to last anywhere near the average 200k mile lifespan for a Honda engine, in fact it only lasted 20k before it launched a piston through the head. That's the problem with keeping internals stock and spinning more RPM.
 
sketch424
maybe it sets it automatically because we cant set the RPM limit ourselves like you would be able to in reality with racing chips. (electronically controlled engines)
Click to expand...


Its obviously done automatically, But IRL after fitting new higher sec exhaust parts, you would set vehicle on a rolling road and adjust ecu as neccesary or if car was pre ecu/injection you would revert to setting up the car the traditional way IE bigger jets in carbs or fitting different cams etc.
 
The ECU upgrade (+200 rpm), the sports catalytic converter (+200 rpm) and NA tuning stages (+100 rpm each) increase max rpm as well. Engine rpm can be increased at most by 900 rpm.
However in my opinion only NA tuning steps would make sense for this operation (where engine internals and valvetrain are replaced, rebalanced, etc and therefore the rpm limit can be safely increased).

Engine tuning in GT5 isn't very realistic anyway. Torque/power curves don't change shape (except with turbo kits), the rpm increase with modding is minimal and specific torque (torque/engine displacement) reaches unrealistic values (which means that power is attained at too low rpm compared in real life. A NA tuned 270 hp 2 liters engine for example should reach is peak power at around 9000-10000 rpm, not just over 7000 rpm like what happens on the premium Alfa Romeo 147).

PD should really rebuild from scratch the whole tuning system.
 

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