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991.2 Carrera Aftermarket Intercooler Poor Performance On Track
I have been testing various components on track in order to improve performance. In testing I have data logged hundreds of laps with various sets of tires, fuels, performance parts.....Recently we installed a set of intercoolers and did some testing with some unfortunate results.
Below are graphs of IAT's and Boost Pressure which are typical of before and after the modifications. Based on this data it appears that the thermal mass reduces the peak temps by a few degrees but also raises the IAT's during lighter loads. So for drag racing you might see some reduced temps for short pulls but in a lap at speed on track the mass is heated and there is no or possibly a negative impact.
In addition to the 991.2 Carrera I have also been able to data log a Turbo and GT2-RS on track. The Turbo was similar to the Carrera however the GT2-RS with the water sprayer never broke 130°F using the water sprayer!
There's a big difference between a part that adds power on a dyno pull and a fully developed part that's been tested in the extreme heat of Death Valley and South Africa as well as Alaska in the depth of winter—and the German autobahn for hours on end.
Good data. Tyler at APR had reported similar findings when using the base Carrera turbos in his T. A good chunk of the issue is getting airflow in/out of the ICs which is why they were relocated on the 992. What size turbos are you on?
Good data. Tyler at APR had reported similar findings when using the base Carrera turbos in his T. A good chunk of the issue is getting airflow in/out of the ICs which is why they were relocated on the 992. What size turbos are you on?
This is on a GTS so it does have a bit larger turbo's, same as the X51. I had seen some of the Turbo folks talking about this but I am not sure if the results were quite as dramatic given the better air flow to the coolers.
In my opinion the car would benefit greatly from large scoops in the rear to grab more air but by far the biggest improvement I have seen is the intercooler sprayers on the GT2-RS.
My next move will be to get a spray system rigged up, the only struggle is if it is spray internally or externally. My preference for this car would be pre-turbo but I think it will need to be post intercooler spraying conterflow.
This is on a GTS so it does have a bit larger turbo's, same as the X51. I had seen some of the Turbo folks talking about this but I am not sure if the results were quite as dramatic given the better air flow to the coolers.
In my opinion the car would benefit greatly from large scoops in the rear to grab more air but by far the biggest improvement I have seen is the intercooler sprayers on the GT2-RS.
My next move will be to get a spray system rigged up, the only struggle is if it is spray internally or externally. My preference for this car would be pre-turbo but I think it will need to be post intercooler spraying conterflow.
Yup, scoops would be the way to go. I would avoid pre-turbo as the water droplets will erode the compressor wheel. There are applications, particularly diesel with high EGR rates, which use electroless nickel plating on the compressor wheels to make them strong to handle particles hitting them from the EGR. But your standard gas turbo compressor wheel won't have that plating applied. I think the best place would be right after the compressor discharge. The air temp coming out of the turbo can be in the 400F-500F range if running 20+ psi of boost. That should vaporize any water pretty much instantly and I think you'll get the most benefit spraying there. As you now, the phase change of water from liquid to gas absorbs tons of heat. There is some risk of the water condensing going through the intercooler though. The safest best is just to spray on the exterior surface of the intercooler on the hot side, but it won't be as effective at cooling. If you spray into the charge piping, just spray very low mass flow. If you spray in the charge pipe after the intercooler, the air would have been cooled down significantly already and I don't know that the water would absorb as much heat.
Well, the two options out there are AMS and Tial. There are some design differences between the two, but nothing visibly drastic to make me think they'd perform drastically differently. Eyeballing the available pictures, they both use bar and plate cores, but the AMS looks to have fewer rows, so maybe thicker bars.
All the kits I have seen are nearly the same, I can imagine that the manufactures here are not thrilled about me posting this detail so here are some photos for reference. Note that the aftermarket cores have much lower fin density than the OEM but the overall mass is considerably higher.
This is upsetting as I just ordered some intercoolers and inlets. From the photos these do not appear to be Tial, but AMS. Correct me if I am wrong.
Also, the APR website indicated lower temps and higher torque and HP with intercoolers, so someones data isnt correct..
There's a big difference between a part that adds power on a dyno pull and a fully developed part that's been tested in the extreme heat of Death Valley and South Africa as well as Alaska in the depth of winter—and the German autobahn for hours on end.
What was ambient Temps when you logged those intake temps?
I have tested between 60-95F Ambient on track, the two data logs shown above were a 95F day with stock parts and 85F day with the intercoolers installed. It is interesting that ambient temps make less of a difference than you would think.
Originally Posted by PTS-BRG
This is upsetting as I just ordered some intercoolers and inlets. From the photos these do not appear to be Tial, but AMS. Correct me if I am wrong.
Also, the APR website indicated lower temps and higher torque and HP with intercoolers, so someones data isnt correct..
You have to read between the lines when it comes to marketing! I would guess the APR probably has the best data out there with the extents of there testing but getting past sales to someone with the knowledge to discuss the specifics has been impossible for me to date.
Originally Posted by stout
There's a big difference between a part that adds power on the dyno pull and a fully developed part that's been tested in the extreme heat of Death Valley and South Africa as well as the Alaska in the depth of winter—and the German autobahn for hours on end.
You are 100% correct the extents that the OEM’s go for testing dwarfs the aftermarket manufactures. 99% of upgrades are a comprise of manufacturing cost, reliability, emissions or comfort there is no such thing as free performance anymore. The only exception I have seen are cars like the R8, 981’s.... that are detuned to make model tiers following the good, better, best marketing strategy.
Do you feel a water/methanol injection system will provide better results? This is the route I am planning to take with the stock intercoolers in place.
What is the pressure drop across the intercoolers at max boost?
What is the efficiency of the intercoolers?
Back in the day with my 3rd gen RX-7 this info was always being dissected for both the 1/4 mile and track use.
FWIW, intercooler sprayers do work, and there are various setups available, triggered by boost, temps, combinations of the 2, 'estimated' load etc. Can get away without additional tuning and just try an improve efficiency of the intercooler.
A methanol/water injection system would be even better, but would require tuning if running the ragged edge.
I think there are two main variables here. One being drag or road course. The other is being power level. For the intercoolers themselves, there's how well they cool and how much pressure drop they create in the internal flow. For a drag race/single pull situation, the extra thermal mass will keep the IATs down. AMS shows this data on their website. On a road course, the situation changes a bit. I will note I was told that at, call it 500whp levels, on a road course that the aftermarket intercoolers showed this same behavior as dsddcd observed. On a road course, the stock intercoolers do get hotter than the aftermarket options, but the stock ones cool down faster too. So exactly what dsddcd shows. However, this changed at higher power levels, call it 600whp+. This is just hypothesizing on my part, but at the lower power/airflow rates, the extra thickness of the core isn't being used because the air isn't flowing into it. Basically, the airflow isn't going into the extra sections of the thicker IC, so it's basically not cooling as well as it good. And because the core is thicker, there's less external airflow going through it. But as the boost/power/mass airflow got turned up, the extra airflow is now flowing into the extra thicker core section which gives more surface area to shed head and also reduce internal pressure drop.
So just my hypothesizing based on available data, but if you're staying around 500whp and your car is a road course car, there may not be much to gain going to an aftermarket IC. But if you're in the 600whp+, it seems there is benefit. If all you do is drag racing, the ICs should help regardless power level.
Do you feel a water/methanol injection system will provide better results? This is the route I am planning to take with the stock intercoolers in place.
Yes, I have seen the results on the GT2-RS and the IC sprayers (External) make a big difference, 30-40F when I was data logging. As for the Injection, this will have an ever larger impact but the risk is also greater. I never recommend a car be tuned for Injection unless sufficient time and money is spent developing the system which in my experience is $3-5K for hardware and time spent tuning, assuming standard labor costs. Generally it is much better to switch fuels or upgrade other components.
If you are interested in doing a internal spray check out Aqua Mist they have a very nice system for aftermarket. However the best example known to me is the M4 GTS, they have an integrated system which is far superior than anything I have seen elsewhere.
Originally Posted by thesaintusa
What is the pressure drop across the intercoolers at max boost?
What is the efficiency of the intercoolers? Back in the day with my 3rd gen RX-7 this info was always being dissected for both the 1/4 mile and track use.
Unfortunately this is not known, I do not have a flow bench or system to measure the resistance or thermal efficiency. Regardless of what I read, generally I test components in some cases much more than the manufactures themselves. So you could say that my testing is flawed and I could not argue but I can say that what testing that was done yielded results, with my setup, which were not favorable give the amount of time and money spent.
Originally Posted by spdracerut
I think there are two main variables here. One being drag or road course. The other is being power level. For the intercoolers themselves, there's how well they cool and how much pressure drop they create in the internal flow. For a drag race/single pull situation, the extra thermal mass will keep the IATs down. AMS shows this data on their website. On a road course, the situation changes a bit. I will note I was told that at, call it 500whp levels, on a road course that the aftermarket intercoolers showed this same behavior as dsddcd observed. On a road course, the stock intercoolers do get hotter than the aftermarket options, but the stock ones cool down faster too. So exactly what dsddcd shows. However, this changed at higher power levels, call it 600whp+. This is just hypothesizing on my part, but at the lower power/airflow rates, the extra thickness of the core isn't being used because the air isn't flowing into it. Basically, the airflow isn't going into the extra sections of the thicker IC, so it's basically not cooling as well as it good. And because the core is thicker, there's less external airflow going through it. But as the boost/power/mass airflow got turned up, the extra airflow is now flowing into the extra thicker core section which gives more surface area to shed head and also reduce internal pressure drop.
So just my hypothesizing based on available data, but if you're staying around 500whp and your car is a road course car, there may not be much to gain going to an aftermarket IC. But if you're in the 600whp+, it seems there is benefit. If all you do is drag racing, the ICs should help regardless power level.
I would agree with this assessment. My car made 504WHP, if there were more flow then in theory the factory coolers would become a bigger restriction and require that the turbo be pushed further to the right of the efficiency curve yielding higher discharge temperatures. I would also theorize that the addition of an intercooler sprayer would provide more benefit with the larger and more massive cores.
In short the cores are not useless but for the majority of folks the benefits for upgraded turbo's, intercooler sprayers or alternate fuels far out weighs the benefits of the intercoolers. If I was able to find a reliable tuner I would gladly spend the $5K from the intercoolers and other mods and put on a set of turbo's.
08-02-2020, 01:47 AM
991.2 Carrera Aftermarket Intercooler Poor Performance On Track
