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...plus the additional heat they will generate in the cruise areas between 3-4krpm as they will constantly want to get on boost.
This is actually a very interesting point to me that I had not considered or thought about. Is there a substantial heat increase due to this? I understand pushing a turbo and such generates a lot of heat, but this seems like it would be only leisurely spooling at that point. Hard to get my head around why it would cause any substantial heat increases - but seems viable.
Heat management issues are one of the main reasons for this refresh which is how the damage to my original turbo was discovered followed by multiple expletives unleashed into the atmosphere. I may have dodged an additional heat soak item the new cooling system would need to further overcome. Texas heat sucks.
I didnt notice any change in egt or ait at freeway cruise going from laggier 57mm turbo to EFR 57mm turbo.
I noticed a huge increase in thermal load racing laggier 57mm turbo at 14psi versus 57mm EFR at 26psi- which is to be expected.
I did take a decent hit in freeway cruise MPG with the EFR because I had tuned for throttle response not MPG- so popping into boost so easily was ~4mpg worse on curvy/hilly freeway on my tune (17mpg vs 21mpg)
There are ways around that as modern cars with selectable driving modes prove.
As far as freeway cruise it takes X amount of power to push your car at X speed and spool time is not a factor with constant vehicle speed.
There are means of mechanical plumbing/simple solenoid operation to help with that, you can use the pressure drop across the throttle to help keep the gate cracked at cruise if so desired with aftermarket gates.
This is actually a very interesting point to me that I had not considered or thought about. Is there a substantial heat increase due to this? I understand pushing a turbo and such generates a lot of heat, but this seems like it would be only leisurely spooling at that point. Hard to get my head around why it would cause any substantial heat increases - but seems viable.
Heat management issues are one of the main reasons for this refresh which is how the damage to my original turbo was discovered followed by multiple expletives unleashed into the atmosphere. I may have dodged an additional heat soak item the new cooling system would need to further overcome. Texas heat sucks.
It is important to note that a more responsive turbo does not always mean a higher EGT (in modern vehicles like the M3/M4/Turbo S) but on a rotary platform, I'm afraid this is not the case.
A more responsive turbocharger typically has a smaller turbine and compressor, which allows for a much quicker response to changes in engine load or throttle input. It can deliver a higher volume of compressed air to the engine. This increased responsiveness of the turbocharger results in higher EGTs during low load cruise conditions, So either the tuner can compensate by running the map rich to control EGT's meaning less efficiency/MPGs but better response. It is trade off, a compromise. The smaller turbine and compressor size will also generate higher exhaust gas flow rates and temperatures, which again raise the EGTs.
In general, a more responsive turbo can generate higher EGT during cruise conditions. This is because a more responsive turbo can provide more boost to the engine at lower rpm more easily (than a bigger turbo designed for lower EGTs), which leads to higher combustion temperatures. Additionally, a more responsive turbo will likely be hovering near atmospheric pressure or just below into vacuum under low load (cruise conditions when stabilized in steady state) and if you apply 10-15% throttle hovering at 3-4krpm cruise conditions this can immediately put you above atmospheric pressure, meaning positive boost pressure leading to higher EGTs.
A larger turbo cant generate instant boost like that unless you go 30-50% throttle opening or WOT to wake it up, its much easier to do so with a smaller responsive turbo with less throttle input, at least in my experience (and I'm talking about a very old TO4E/S, which would do this). You can imagine the latest and greatest smaller turbos will be even more sensitive to throttle input under cruise conditions.
Garrett G-series and the EFR's are designed with advanced aerodynamics and improved efficiency and if you believe all their marketing hype they aim to balance performance and response while minimizing excessive EGTs. So these turbos may help improve EGT efficiency compared to older turbos.
Ultimately, the effect of a more responsive turbo on EGT will depend on a number of factors, including the engine, the turbo, the fuel, the efficiency of the cooling system and the tuning. However, in general, a more responsive/smaller turbo will contribute to overall higher EGTs and not the other way around i'm afraid.When the turbocharger is operating at lower RPMs, it may not produce as much boost pressure, but it still creates some level of pressure in the intake system. This pressure can cause a slight increase in temperature as the air is compressed. Additionally, the turbocharger itself generates heat due to the high-speed rotation of the turbine and compressor wheels. This heat can be transferred to the surrounding components, further raising the overall temperature in the engine bay.
Furthermore, the increase in heat can be exacerbated by other factors, such as ambient temperature and the efficiency of the cooling system. In hot climates like Texas, where the ambient temperature is already high, the cooling system needs to work harder to dissipate heat effectively. If the cooling system is not designed to handle the additional heat generated by the turbocharger, it can lead to heat management issues you are experiencing and potentially cause damage to various engine components, including the turbocharger itself. Did you mention your's exploded?
By refreshing your cooling system, you can improve its capacity to manage the increased heat generated by the turbocharger, thus reducing the risk of heat-related damage. It's always important to ensure that your vehicle's cooling system is in good condition, especially when operating under high-temperature conditions or high boost conditions which will increase the heat load on the cooling system.
I am also experiencing heat management issues but under high load and high boost conditions 22psi and above, so need to ensure my dp, exhaust mani, lim, turbo have sufficient heat shielding and also take a closer look at improving the ducting to my oil, radiator and inter-cooler cores. For climates such as your's might be worth taking a closer look at interchiller cooling systems rather than air to air.
A whole lot of ifs, buts and maybes there. Steady state cruise with good intercooling a larger pressure drop across the throttle will likely actually see lower final intake manifold temperatures due to the gas expansion effect. Likewise a somewhat higher EMP will increase EGR effect resulting in lower peak combustion temperatures and less reject heat to cooling system for a given air/fuel flow (that's why manufacturers use it to curb oxides of nitrogen), although exhaust manifold gas temp will be higher. Different story if you are bouncing on and off significant load.
Some initial results with the G35-900 - target 400 max. 102 degrees today:
Many turbo gurus have said this already but your data proves it. 18psi boost and you're at sub 400hp. No chance the G30-660 would have made anywhere near that power level!
The only thing you're missing is a dragy 100-200kph pull...that would give us a real indication of how the car's acceleration really is!
the results look weird as to when 18 psi was obtained... around 4700. do you know if there was a reason. i would have thought 3900 or thereabouts. could there be some issues w the setup?
the results look weird as to when 18 psi was obtained... around 4700. do you know if there was a reason. i would have thought 3900 or thereabouts. could there be some issues w the setup?
Not going to lie, I'm not overly impressed with what I'm seeing there and not feeling like it was worth "upgrading" from over decade-old tech at the moment. That is as slow, if not slower than the GT35R making the same HP with less torque at 2 more PSI (GT35R was around 16 psi). I was assuming temperature had a lot to do with it since the results I have from the other setup were done on a cooler day. The previous set up was with M2 medium IC and this is a Greddy v-mount - I chalked up the increase in PSI needed to a larger intercooler.
This is their first experience with this turbo - what questions should I ask? What should they be looking for?
They were not really impressed either but figured this was how this turbo behaves on a rotary. They did say it was easier to get to 400 than the GT35R but seems like an almost on-par result for about 3x the money.
Butt dyno will tell, but those lines didn't make me feel overly wonderful.
Many turbo gurus have said this already but your data proves it. 18psi boost and you're at sub 400hp. No chance the G30-660 would have made anywhere near that power level!
The only thing you're missing is a dragy 100-200kph pull...that would give us a real indication of how the car's acceleration really is!
Final run after tune. Had let her rest a bit to get cooled down, etc. 91 degrees. This looks a bit more like I expected.
Additionally, the other run was in 3rd gear - this is 4th.
What's controlling the boost on this engine? It looks like it's purposefully ramped in slow to keep the top end a little happier but with sacrifice to the low end.
a G35-900 1.06 T4 should be capable of mid-500 range with all the correct mods and support components
in addition to the weak boost curve up to 4000 rpm, looks to me like there are flow restrictions on the intake and/or exhaust. Some of it appears to be conservative tuning possibly. The one advantage of the Renesis is that the factory 6-port intake/ports will flow better than the factory REW intake/ports, enough to support 270 bhp NA. Which was what the REW TT was rated at from the factory.
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What's controlling the boost on this engine? It looks like it's purposefully ramped in slow to keep the top end a little happier but with sacrifice to the low end.
Greddy Profec Type S
Originally Posted by TeamRX8
a G35-900 1.06 T4 should be capable of mid-500 range with all the correct mods and support components
in addition to the weak boost curve up to 4000 rpm, looks to me like there are flow restrictions on the intake and/or exhaust. Some of it appears to be conservative tuning possibly. The one advantage of the Renesis is that the factory 6-port intake/ports will flow better than the factory REW intake/ports, enough to support 270 bhp NA. Which was what the REW TT was rated at from the factory.
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Keep in mind, the target was 400 max. I didn't want more than that as I am pump gas and no AI. So a conservative tune is quite right.
Intake is possible but I would think unlikely - I'll look into it. It's a K&N of some form but I forget which. Viable or no?
The exhaust is just a downpipe, resonated mid-pipe, and an old Greddy EVO (if I remember correctly). From what I understand, it flows fine. There were some additional modifications needed to the exhaust as the downpipe terminated in the new transmission brace. While it added some restriction over straight, I can't imagine it was a lot:
One thing you dont have that I found helped spool (data log confirmed) is a velocity stack on the end of the intake and a 8" base 12" long K&N filter.
The hot weather conditions were definitely affecting your spool up and unlike peak power #s the dyno cant correct for it.
Like you say, the dyno spool and power doesnt look like anything we havent seen from 20 or 30 year old turbos- but hopefully the response is much better.
P.S. the engine doesn't care if you are going to get it later.
sorry but another one of my irritants are shops that use STD correction instead of what is used by shops as well as the OE world who play it straight. by clicking on STD instead of SAE you magically gain 3% power... so deduct 12
Last edited by Howard Coleman; 06-28-23 at 11:56 AM.
You can definitely squeeze a bigger air filter in that corner. I had the same V mount set up on an efr8374 and the numbers at that psi were really close to what you're seeing on a similar dyno and on a factory port job. I have a suspicion the greddy v mount is a restriction.
I would bet with an actual tuned duty cycle map for boost control you would get a lot quicker spool in and the curve would be more rainbow like instead of a ramp up. The boost controller holds boost solid, but I would bet that's holding it back.
The exhaust is just a downpipe, resonated mid-pipe, and an old Greddy EVO (if I remember correctly). From what I understand, it flows fine. There were some additional modifications needed to the exhaust as the downpipe terminated in the new transmission brace. While it added some restriction over straight, I can't imagine it was a lot:
its easy to test, you can put some kind of pressure sensor or boost gauge in place of the O2 sensor. it does need a length of brass tubing to keep the heat in the sensor/gauge reasonable
in real life anything over like 3-4psi is bad.
pic is mine, its just an O2 plug, compression fitting and the tubing, goes to an old boost gauge
One thing you dont have that I found helped spool (data log confirmed) is a velocity stack on the end of the intake and a 8" base 12" long K&N filter.
The hot weather conditions were definitely affecting your spool up and unlike peak power #s the dyno cant correct for it.
Like you say, the dyno spool and power doesnt look like anything we havent seen from 20 or 30 year old turbos- but hopefully the response is much better.
Interested in hearing your driving impressions.
Me too! Butt dyno tells all eventually. This appears to be getting me cold-weather GT35R performance on a hot day so an improvement. But I think Brettus called it early - a lot to spend for on-par(ish) results. I'll look into the intake you mention - thank you!
Originally Posted by Howard Coleman
" the target was 400 max. I didn't want more than that as I am pump gas and no AI."
yes, that sounds real conservative. 400 is 460 flywheel v 255, only about double the output. you can do just fine at 400 with no AI.
P.S. the engine doesn't care if you are going to get it later.
sorry but another one of my irritants are shops that use STD correction instead of what is used by shops as well as the OE world who play it straight. by clicking on STD instead of SAE you magically gain 3% power... so deduct 12
I don't disagree - but this is also why I've done a staged approach. I've always felt like 350 was pretty much the max without AI you can get consistency and reliability with a (relatively) conservative or proper tune. So, I went with a 3 stage approach. 276 whp to cruise around, 350 when needed, 400 only with race fuel on rare track days. I went with 3mm apex seals back in the day as an added precaution - no idea if that helps or hurts these days.
I will eventually get AI, as I'm fairly sold on it. What I am not sold on is the tech at the moment. What was amazing and solid is now being seen to fail, with electrical issues, nozzle problems, metal flaking, etc. I've hovered around the topic for ~14 years now. As soon as I make a decision, the company is sold or parts out manufacturing to cheaper items with less QC, etc. There is so much cheap crap in the market being sold at a premium that it's been hard for me to finally make a decision. So, building the car around being safe without it for the time being has been the goal. Either way, I'm always watching your posts and tests with updated items.
Originally Posted by newtgomez
You can definitely squeeze a bigger air filter in that corner. I had the same V mount set up on an efr8374 and the numbers at that psi were really close to what you're seeing on a similar dyno and on a factory port job. I have a suspicion the greddy v mount is a restriction.
I would bet with an actual tuned duty cycle map for boost control you would get a lot quicker spool in and the curve would be more rainbow like instead of a ramp up. The boost controller holds boost solid, but I would bet that's holding it back.
Interesting, I'll look into it. As far as I know there isn't much advanced boost control or variable suffs in the Type S. Basic and reliable was the goal there.
Originally Posted by j9fd3s
its easy to test, you can put some kind of pressure sensor or boost gauge in place of the O2 sensor. it does need a length of brass tubing to keep the heat in the sensor/gauge reasonable
in real life anything over like 3-4psi is bad.
pic is mine, its just an O2 plug, compression fitting and the tubing, goes to an old boost gauge
Interesting - I'll see what I can do about checking that eventually. Now I'm quite curious.
05-24-23, 05:41 PM
