Sale ends todayGet 30% off any course (excluding packages)
Ends in --- --- ---
Discuss all things tuning in this section. News, products, problems and results.
What do you recommed to do to a stock EVO IV in terms of engine without modifying internals.
Bigger turbo and bigger injectors and a good tune and dual map one on pump gas and other map on e85 .fuel pump also need a upgrade.
I'd be very cautious with the EVO 4. The EVO 4 block suffers badly from crank walk issues that are well known with the early DSMs. The thrust bearing issue was dealt with in the EVO 5 and later blocks where they went to a separate thrust bearing as opposed to the thrust bearing being integral with the centre main.
This isn't specifically a power related issue and I've seen stock standard EVO4 engines suffer thrust bearing failure. My advice if you're going to keep the stock block would be to always make sure you have free play at the top of the clutch pedal, stay away from clutch kits with very heavy pressure plates, and never start or stop the engine with your foot on the clutch.
Not a specific answer to your question but hopefully you can benefit from my years of experience with the 4G63 :)
What is the boost limit for a stock block and internals for an EVO IX
Boost isn't that relevant in terms of defining a limit as it's really the airflow into the engine that defines how much torque we can make and this in turn is what will typically break an engine. What I mean by this is that 30 psi boost on a stock EVO IX turbo is going to produce a very different amount of torque than 30 psi on a Garrett GT42 for example.
I typically limited engine power to around 300 kW atw on a dynapack dyno for the EVO 7-9 and never had trouble with engines failing at this level. We also built an EVO IX running a stock block that we pushed to approximately 500 kW atw without failure. This is above my recommendation though and was only done as the owner specifically wanted to chase a certain record using a stock block.
How much torque had the 500kw stock block Evo and what fuel have you used? How long did it last? I usually worring most about stock rods. Most piston are fine as long as there is no knock. I made good experience with limiting the torque, means tappering the boost up with RPM.
What I'm not sure until today is, what applies more load to the rods. Let's say you reach 500Nm in 3 different way, what are the saves way?
- Boost as low, timing as high as possible
- More boost, less timing
- A lot of timing with E85, little boost
If you want to reach 450 hp on and EVO IX MR what mods would you consider doing?
I can't remember exactly how much torque the EVo IX we built made now as it was about 5 years ago. We did taper the boost up as rpm increased and purposely reduced the timing around peak torque to help control the load on the rods. That engine was tuned on E85.
It really doesn't matter what combination of boost, timing and fuel you're running (provided obviously no knock is occurring), if you're seeing 500 Nm of torque then you have the same amount of pressure acting on the top of the piston and hence the stress being applied to the engine internals is the same.
My personal approach to tuning a high boost turbo engine is always to use a little more boost and a little less timing. The net effect of stress on the engine is the same however this provides a little extra buffer to the point of knock incase something goes outside of the operating envelope you experienced while tuning.
@fgallego are you meaning 450 whp or at the crank? What fuel? There are literally dozens of turbo options on the market that will achieve these aims. One of the turbo combos I used a lot at my old shop was a Garrett GT3582 which coupled with a mild set of cams, a suitable exhaust and a fuel system upgrade was capable of 400-450 whp on pump gas. Times have moved on since the GT35 though and these days I'd be inclined to look at a Borg Warner EFR instead.
Andre, Adrian, let me say that no the stress is different between the two combination high boost/low timing and low boost/high timing.
For a same torque, maximum cylinder pressure peak is higher with low boost/high timing this can create oil film/cylinder head gasket/movings parts rupture by mechanical fatigue.
With High boost/low timing the cylinder pressure spread f(°CA) is higher, it is less stressful generally but there are risks for piston skirts if the spread is very high. For me this is the safe way ;)
I'll disagree Leo in so much as any cylinder pressure variation is unlikely to be significant enough to effect engine strength in my opinion. It takes x amount of cylinder pressure acting on the top of the piston to create a certain amount of torque so within reason if you've got that amount of torque then you're going to have x amount of cylinder pressure. Of course there may be some minor differences in the shape of the pressure vs crank angle graph but this is unlikely to have a significant difference in the engine's reliability when comparing the two approaches to get to the same result. Hopefully in the not too distant future we will be able to bring a practical demonstration of this through the use of in cylinder pressure transducers to show exactly what's going on.
The point I'm getting to however is that regardless of your technique, the net cylinder pressure will be close enough to being the same not to matter. If the engine suffers knock however all bets are off and this can easily damage an engine that is mechanically near the limit of strength. This is why I prefer to use more boost and less timing to provide a wider threshold or safety margin to knock.