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Old 06-08-2009, 04:33 PM   #1
Cobb Tuning
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Default HTA68 Comparisons and Tests - Surgeline Tuning

With all the talk about the new HTA68 turbo, I thought it would be informative to post up a few results from the application of this turbo. It has been suggested that this turbo is somehow both a 16G with the power of a 20G. We had the opportunity to test the HTA on a 2.5L 08 STI, as well as a 2.0L WRX.

Before looking at the results, please save all of us the trouble of not posting up the obvious: Yes, the 08 STI test was not perfect as it was not a real stage 2. Yes I know it would be better on a complete stage 2. Yes I compared it with a real Stage 2 stock turbo. Yes it would be nice to have a 20G 2.0L to compare to. These results are just that: Results. They do not provide all of the information to make a complete conclusion. They do however contain some interesting insights for the more intellectually blessed. Please read on.

** We will have a HTA68 STI Full Exhaust Test later this week.

To start, let’s look at the HTA68 on a 2.0L WRX.



This WRX was prepped with a complete stage 2 exhaust, external wastegate, and a set of equal length headers. Ported TGVs, DW850 injectors and 255lph fuel pump. On a 2.0L, I would consider this a bit of a laggy turbo. Power up top was fantastic, and on the 23psi Torco run power peaked at 348whp! 15psi at 4400 rpm, full spool at 4700 rpm.
A logical comparison would be an 18G or a 20G. I didn’t have any 20G direct plots to compare with (on 2.0L), but I did have a good 18G comparison.



This comparison shows an 18G-5H-7cm compared to the HTA68 on a 2.0L WRX. Boost threshold with the 18G is obviously better by about 1000rpm. Once on boost however, at the same or similar boost levels the HTA68 performs better. While the 18G can hold 19psi to redline, it is clearly running out of efficiency compared to the larger HTA68. Had I not know what turbos were being compared here, I would have guessed an 18G and a 20G, perhaps even a 20G-6H.

On a 2.0L, this turbo makes great power, but it is a bit laggy (as a 20G might be). For many this would not at all be an issue, and the gains up top for a turbo of this price makes this a good choice if you are looking to make >330whp.

Turning up the boost a bit, let's compare a slightly higher boost level with the HTA68 and the 18G:



Here you can see with the boost at 22psi on the 18G 320-330whp is possible. With the HTA at about 23psi and with Torco added 350whp was touched on. That is pretty good power on a 2.0L with a nice bolt on turbo. The 18G outspools the HTA68 by about 600rpm here.

Summary for the 2.0:

Performance of the HTA68 seems similar to what a 20G might do on a 2.0L. Boost threshold is better with the 18G, but once spooled the HTA68 can outperform the 18G. Give the price point of the HTA68 ( it is at least a few hundred dollars less then the 20G ), it is a good alternative if you are looking for the 330+ whp range on your 2.0L. Obviously if lower end torque and boost threshold is a critical consideration, a 16G/18G might be a better choice.

Let's switch over to the 2.5L space.
For this test, we tuned an HTA on a 2008 STI with an aftermarket downpipe (single cat), and with the STOCK mid pipe and muffler. This is not a real stage 2 configuration, but something the customer wanted to try. As you can imagine the stock muffler is both quiet as well as restrictive. Fortunately we had a 20G customer who also tuned with a stock muffler.

We can start with the results of the HTA68 on the 08 STI:



Boost threshold is very good, stock level boost threshold in fact. Upper end power was not great, although based on the 2.0L results I would suspect this may be caused by the significant backpressure from the stock mufflers. While the turbo could hold a solid 20psi, power was the same rolling down to 19 at redline.

The overall results look similar to a 20G-7cm. Sure enough..



This is not a direct apples to apples comparison for a couple of reasons: First these are uncorrected results, and the 20G tune was done in 30 degree cooler weather. Second the 20G car had the perrin headers, which once hot can help spoolup a bit. If you factor in those differences, these two turbos perform about the same. Similar spoolup, similar power, similar torque.

It is possible that a difference might occur at higher power levels (and with a real exhaust), however I suspect the performance will be close. This new HTA68 is much like a 20G, but of course at a cheaper price level. Nice.

When comparing to a stock turbo, I consider both a more direct comparison with a car also with the stock muffler:



Here you can see how the stock turbo boost threshold was actually a bit worse, but this is comparing a stock downpipe vs an aftermarket one. Once the HTA is in the power, the stock turbo is significantly under the curve. Boost falls off up top, and power is down 50whp.

Switching to a Stage 2 STI setup:



This shows a real Stage 2 STI with downpipe compared to the HTA68 with downpipe but stock muffler. Obviously a real stage 2 to HTA with stage 2 exhaust would be a better comparison, but this is instructive. Consider the thought process here.. You have X dollars to spend on your bone stock STI. What should you do?

In this case, you could spend $1000 on the HTA68, plus perhaps $300 on the downpipe, or $1100 on a complete Stage 2 exhaust. With the HTA you get near factory noise level and a bit more power to boot. On the flip side if you are going to do a stage 2 anyways, the gains are pretty close. Clearly adding the HTA to the Stage 2 would give the best results.

Summary for the 2.5:

Good results on the HTA, but nothing spectacular. Performs like a 20G in this test case. Given the cost is less, it has an advantage. Boost threshold on the HTA is probably a bit better then the 20G in identical test cases (same headers, temp, etc). Clearly an 18G might spoolup a tiny amount sooner, but since this combo can get near stock spoolup in these test cases, why not get the extra headroom of the 20G/HTA68.

I am not sure why anyone would compare the HTA68 to the 16G. Yes it makes more power, but even the 18G outspools it on a 2.0L. The direct comparison would be with the 20G. A 20G 8cm will likely be a bit later in spooling, but might be a bit stronger at higher hp levels.

Jeff Sponaugle
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Old 06-08-2009, 04:34 PM   #2
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.. Space for a few more plots ...
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Old 06-08-2009, 04:54 PM   #3
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Nice writeup. Very unbiased and informative.
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Old 06-08-2009, 04:58 PM   #4
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Jeff, was that my car? If so, the Perrin Downpipe is the two-cat version.

The cat-back will be here Friday I can't wait to see if it helps...

Also, again assuming this is my car, the plotted pulls above are with the foglight cover removed if I remember correctly, which is important based on the little testing that I did of the AEM CAI.

http://forums.nasioc.com/forums/show....php?t=1780757

Cheers.
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Old 06-08-2009, 05:03 PM   #5
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Quote:
Originally Posted by tazswing View Post
Jeff, was that my car? If so, the Perrin Downpipe is the two-cat version.

The cat-back will be here Friday I can't wait to see if it helps...

Also, again assuming this is my car, the plotted pulls above are with the foglight cover removed if I remember correctly, which is important based on the little testing that I did of the AEM CAI.

http://forums.nasioc.com/forums/show....php?t=1780757

Cheers.
Yes, I'll correct it for the two downpipe. Indeed the AEM intake was pretty warm... or more to the point the sensor reads pretty warm. The actual air temp was not that hot, but the sensor heat soaks.

I looked at the logs before and after the foglight, and there was very little difference. A few hp, but nothing huge. Run to run variance was a bit more due to temp changes.

Jeff
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Old 06-08-2009, 05:15 PM   #6
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Is the 7cm 20G using a TD05H turbine wheel? I would guess so, looking at the plots. And it would make sense that the HTA compressor wheel is basically acting like a 20G compressor wheel because of the fin shape, making it like a TD05H 7cm 20G turbo.
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Old 06-08-2009, 06:02 PM   #7
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Quote:
Originally Posted by sponaugle View Post
Yes, I'll correct it for the two downpipe. Indeed the AEM intake was pretty warm... or more to the point the sensor reads pretty warm. The actual air temp was not that hot, but the sensor heat soaks.

I looked at the logs before and after the foglight, and there was very little difference. A few hp, but nothing huge. Run to run variance was a bit more due to temp changes.

Jeff
Ah. so does that mean that the heat soak of the MAF does not matter so long as the air-charge is really not soaked? I don't know enough about the changes the computer is making based on a registered air charge. It would seem to me one could get much more out of the turbo if the actual and perceived air temp were close or the same measurement.

Last edited by tazswing; 06-08-2009 at 06:10 PM.
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Old 06-08-2009, 06:44 PM   #8
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Quote:
Originally Posted by klattery View Post
Is the 7cm 20G using a TD05H turbine wheel? I would guess so, looking at the plots. And it would make sense that the HTA compressor wheel is basically acting like a 20G compressor wheel because of the fin shape, making it like a TD05H 7cm 20G turbo.
As Tim mentioned below, it is a 6H wheel in the 7cm housing.

Quote:
Originally Posted by tazswing View Post
Ah. so does that mean that the heat soak of the MAF does not matter so long as the air-charge is really not soaked? I don't know enough about the changes the computer is making based on a registered air charge. It would seem to me one could get much more out of the turbo if the actual and perceived air temp were close or the same measurement.
It does matter, as the ECU will pull timing and reduce boost. We were able to account for that on the dyno with tuning, but on the road it would be a factor.

Jeff

Last edited by sponaugle; 06-08-2009 at 07:07 PM.
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Old 06-08-2009, 07:01 PM   #9
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The comparison 20g (blouch) was a 7cm exhaust housing with a 6H turbine wheel. THis is one of my favorite combinations for quick spool on a 2.5 liter

Regards
Tim Bailey
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Old 06-08-2009, 07:09 PM   #10
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Were the injectors upgraded on the 08 STI for the HTA68?
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Old 06-08-2009, 07:11 PM   #11
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Originally Posted by JRSRED10 View Post
Were the injectors upgraded on the 08 STI for the HTA68?
Yes, DW850s. -Jeff
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Old 06-08-2009, 07:11 PM   #12
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Quote:
Originally Posted by sponaugle View Post
It does matter, as the ECU will pull timing and reduce boost. We were able to account for that on the dyno with tuning, but on the road it would be a factor.

Jeff
You could change the IAT temp timing comp tables, and the boost comp tables (depending what year/model).
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Old 06-08-2009, 08:02 PM   #13
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Great information, keep it coming. I tought it would spool sooner than the 20g on the 2 liter.
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Old 06-08-2009, 08:03 PM   #14
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The initial testing was done against a 20G/16G/Dom3. It is slated as a 16G dure to the same housing and a revised wheel. FP was saying it is designed to outperform the 16/18/small 20G family. It is not the end all solution, and I have been saying this for weeks. It is the smallest turbo in the family.

The 2.0 seems to be a bit laggy on the dyno, but it is much more responsive on the street. I have had a few customers attest to this phenomenon.

-J
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Old 06-08-2009, 08:04 PM   #15
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Well these are dyno numbers. How did the cars feel on the street?

Edit: John beat me to the punch haha. I was going to say numbers are numbers but I bet the HTA has better boost characteristics on the street.
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Old 06-08-2009, 10:57 PM   #16
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Thanks for the info Jeff. I hope to add something about this turbo (stage 2 vs. hta68) by the end of the week. The turbo will be here tomorrow!! I currently have an exhaust manifold, tbe, and an intake. The only thing that I am changing is the turbo, so i will have a Airboy dyno comparo.

What kind of traps do you see out of cars that near 350whp on your dyno?
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Old 06-08-2009, 11:42 PM   #17
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Nicely done guys.

was that 2.0 FMIC or TMIC?
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Old 06-08-2009, 11:43 PM   #18
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Quote:
Originally Posted by LittleBlueGT View Post
You could change the IAT temp timing comp tables, and the boost comp tables (depending what year/model).
Correct indeed.

Quote:
Originally Posted by John@Cobb View Post
The initial testing was done against a 20G/16G/Dom3. It is slated as a 16G dure to the same housing and a revised wheel. FP was saying it is designed to outperform the 16/18/small 20G family. It is not the end all solution, and I have been saying this for weeks. It is the smallest turbo in the family.

The 2.0 seems to be a bit laggy on the dyno, but it is much more responsive on the street. I have had a few customers attest to this phenomenon.

-J
The owner can comment about the street performance, so I will leave that to him. Indeed the marketing might be refering to the 16G, but the performance makes the comparison to the 20G a better match. Based on the performance, it may indeed be more responsive on the street. Spoolup on the dyno is a small measure of the lag you feel in real use. I do like this turbo, as I have always really liked the 20G. This seems to perform in a similiar way with some improvements, and the cost is less. That is a win in my book.

Quote:
Originally Posted by STi Mikey View Post
Thanks for the info Jeff. I hope to add something about this turbo (stage 2 vs. hta68) by the end of the week. The turbo will be here tomorrow!! I currently have an exhaust manifold, tbe, and an intake. The only thing that I am changing is the turbo, so i will have a Airboy dyno comparo.

What kind of traps do you see out of cars that near 350whp on your dyno?
Tim can probably comment about that... From my memory that is usually something in the 115-116mph range.

Jeff

Last edited by sponaugle; 06-09-2009 at 10:48 AM.
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Old 06-09-2009, 02:02 AM   #19
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great thread, id love to see what this can do with E85 on a 2.0
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Old 06-09-2009, 11:01 AM   #20
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It is very streetable thus far and pulls through 6500rpm. It also does well with an "I" map which is great for my GF. That may not be a big deal to lots of people, but I got this car b/c it can be very versatile. With this turbo I am hoping to keep the cars suitability for most people who might drive...including my heavy foot.

Generally the car does not feel as good with less than about 10% TP. It likes having a little more fuel running. I know that 10% is super relative now with drive by wire, but this is a drivers opinion.

There is a noticeable "hick-up" around 3200rpm vs. stock, but nothing that seems out of place for the mods on the car.

I still feel the AEM intake is robbing the car of power but that will soon be put to bed.

B/c the HP and TQ are closer together now, the car feels much smoother on acceleration. The change in HP up top is more noticeable than change in TQ.

If Junior wants, he can fly out to Portland and we can go right to the strip some night since I suck a dragging!

I am looking forward to putting on the catback and seeing what else Tim and Jeff can get out of this set-up.

And as always, thank you to Tim and Jeff.
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Old 06-09-2009, 11:18 AM   #21
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can always count on jeff... thanks buddy
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Old 06-09-2009, 11:54 AM   #22
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Quote:
Originally Posted by tazswing View Post
It is very streetable thus far and pulls through 6500rpm. It also does well with an "I" map which is great for my GF. That may not be a big deal to lots of people, but I got this car b/c it can be very versatile. With this turbo I am hoping to keep the cars suitability for most people who might drive...including my heavy foot.

Generally the car does not feel as good with less than about 10% TP. It likes having a little more fuel running. I know that 10% is super relative now with drive by wire, but this is a drivers opinion.

There is a noticeable "hick-up" around 3200rpm vs. stock, but nothing that seems out of place for the mods on the car.

I still feel the AEM intake is robbing the car of power but that will soon be put to bed.

B/c the HP and TQ are closer together now, the car feels much smoother on acceleration. The change in HP up top is more noticeable than change in TQ.

If Junior wants, he can fly out to Portland and we can go right to the strip some night since I suck a dragging!

I am looking forward to putting on the catback and seeing what else Tim and Jeff can get out of this set-up.

And as always, thank you to Tim and Jeff.
The hickup around 3200, and the 10% TPS feel are a result of the larger injectors. There are a few fixes, although none of them are perfect. It seems there are some maps not exposed that are effected by injector size change. Jeff Perrin has been playing around with his map for months trying to get it smooth.

Jeff
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Old 06-09-2009, 12:03 PM   #23
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Jeff, you mentioned the HTA runs + Torco, did you run Torco in the non-HTA runs also?
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Old 06-09-2009, 12:03 PM   #24
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Quote:
Originally Posted by sponaugle View Post
The hickup around 3200, and the 10% TPS feel are a result of the larger injectors. There are a few fixes, although none of them are perfect. It seems there are some maps not exposed that are effected by injector size change. Jeff Perrin has been playing around with his map for months trying to get it smooth.

Jeff
The 2800 - 3200 roughness with non stock injectors,, know it well

Good info on the HTA, I have been an 'over looker' for some time now.
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Old 06-09-2009, 12:10 PM   #25
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Quote:
Originally Posted by Kastley85891 View Post
The 2800 - 3200 roughness with non stock injectors,, know it well
Yup, and why I felt it was expected.

Quote:
Originally Posted by kellygnsd View Post
Jeff, you mentioned the HTA runs + Torco, did you run Torco in the non-HTA runs also?
Not on the STI. But if the injectors have enough left, I would like an E85 map please!
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