T25 vs hx35 flow ratings

[gripandslide]

I guess my question is this,

What psi on an 8 blade hx35 would be equivant to 15 psi on a t25? Is there some kind of ratio or formula?
Thanks in advance

[Frankyy]

An hx35 is right in between the gt30-gt35

I don't know exact numbers but I would say around 20-22psi would possibly come close on a t25 to match 15 on an hx35

Depending on the motor, air flow and all those circumstances the unwritten rule is 8hp per psi on a t25 and approx 12 hp per psi on an hx35

[Croustibat]

You could hardly get 2 more different turbos ...

HX35s are supposed to go on big engines that dont rev. A T25 is for small engines that rev.

Both have extremely different requirements and goals. You know, people dont compare a dog and a sheep just because they are both animals. Same applies here.

[Tom N]

What is the point of this question? Why would you even try to get a hx35 to match a t25?

[jr_ss]

Its most likely to run lower boost so he can drive the car so he doesn't have to get a tune... In short, being a cheapass.

[s14boy]

It would still be 15 psi same shit now if ur wanting to know at what rpm will a hx35 be compressing 15 pounds ths you would neex to know what engine and look up flow sheets for the two turbos.

[gripandslide]

Originally Posted by jr_ss

Its most likely to run lower boost so he can drive the car so he doesn't have to get a tune... In short, being a cheapass.

Bingo. only its not that im a cheap ass, its more of what i can run until i can afford proper supporting mods. the previous owner decided hed put a bigger turbo before getting injectors.

[supersayianjim]

I have a hx35 on my rb25 currently. and I had a hx30 on my rb20 in the past. imo they are great turbos for the coin. the op is prob comparing the 2 because they both use t3 flanges.

I actually had 650cc injecs on my 30 before I ran 22psi on the regular.

on my 25 I can't get past 12-15 psi without some kind of cut, but the funny thing is my nistune says iam only hitting 45% duty cycle on the stock injectors. so go figure!!

[Croustibat]

Originally Posted by gripandslide

Bingo. only its not that im a cheap ass, its more of what i can run until i can afford proper supporting mods.

That is exactly what being a cheapass means. Besides, 15psi off a T25 and 15psi off an HX35 ... there may be a 20-30HP difference between the 2. The difference is the T25 will have full boost by 2500rpm if not before, whereas the hx35 wont have even started to spool at 3000 (on a CA18DET, which has a T25 as oem ... i would not put a standard T25 on an SR20 as it would be quite choking. T25s that come on SR20s are called T25G or T25H most of the time, and are nearly T28s)

Originally Posted by supersayianjim

[...]
on my 25 I can't get past 12-15 psi without some kind of cut, but the funny thing is my nistune says iam only hitting 45% duty cycle on the stock injectors. so go figure!!

That is because you skipped the part where Matt explains you have to multiply that duty cycle by 2 once the engine reach batch mode, because it opens injectors twice per cycle. He has no way to detect this, the duty cycle %age is just (the commanded open time + void blast off time ) / time available. When injectors are fired twice per cycle, the commanded open time is divided by 2. You can see it if you log your duty cycle.

Anyway, with that formula you can reach very high duty cycles and still get normal AFRs (i once hit 65%, and that really means 130%, like opened all the time. Had to go bigger injectors at that time...)

Regardless, if the cut feels like a hard cut, it surely is the TP load cut. Get that one higher.

[gripandslide]

Ahhh I see. Thanks for all the help guys, yeah I know I probably shouldn't be driving my car but its my only car. Btw nice build jr_ss

[KoukiMonsta]

Originally Posted by gripandslide

Ahhh I see. Thanks for all the help guys, yeah I know I probably shouldn't be driving my car but its my only car. Btw nice build jr_ss

Yea jr_ss nice build.

Now gimme some dang burnouts!

Total waste of post

[R@ddy]

Op I understand you 100%.
All others don't understand your question. You're wondering what psi on the HX35 would be equivalent of 15psi out of an T25. the answer would be around 6psi. Run a 7psi spring in the wasyegate and you're good to go. I did this exactly when I had to drive my new motor to get dynoed

[derass]

^^ This is not true. 15 psi would be the same between both these or any other turbos. The difference is the airflow in lbs/min that a given turbo can provide. The T25 has a small compressor and does not produce the airflow required to maintain 15 psi at redline. The HX35 has a much larger compressor and would be able to sustain higher pressure ratios. The larger turbine housing would also provide less restriction and allow for greater peak HP.

[Croustibat]

Originally Posted by derass

^^ This is not true. 15 psi would be the same between both these or any other turbos. The difference is the airflow in lbs/min that a given turbo can provide. The T25 has a small compressor and does not produce the airflow required to maintain 15 psi at redline. The HX35 has a much larger compressor and would be able to sustain higher pressure ratios. The larger turbine housing would also provide less restriction and allow for greater peak HP.

In short, you are wrong, because you forgot about the meaning of MAF. like, MASS airflow sensor.

a t25 at 15psi is already way past its peak efficiency and provides very hot air. an HX35 does not. That is where the difference is. Same flow, same pressure, but cooler air means more mass of air; and it is only that mass of air that matters. Not flow or pressure. Yes there is an intercooler, but it trades flow for temp. While better IAT is always good, it is even better to have lower air temp after the turbo.

Also, peak power is not achieved at redline unless you have serious cams.

[jr_ss]

Originally Posted by R@ddy

Op I understand you 100%.
All others don't understand your question. You're wondering what psi on the HX35 would be equivalent of 15psi out of an T25. the answer would be around 6psi. Run a 7psi spring in the wasyegate and you're good to go. I did this exactly when I had to drive my new motor to get dynoed

No, I understood his question and called it 100% if you read my post.

OP an HX35 isn't going to just "bolt" on. I'm sure you know this but you'll need a new downpipe, charge pipe and intake assemblies. No to mention a T3 foot print manifold.

You can find a good used T25 or T28(run lower boost) pretty cheap around here and call it a day. Then when funds allow upgrade to the setup you want.

Thanks for the compliment.

[Kingtal0n]

it depends on how far away and what sort of material exists between the outlets of both compressors.

As long as you do not exceed the maximum flow capability of the compressors, If we measure the mass of the air per unit volume coming off either compressor you should see the one with higher temperature air contains less mass per unit volume at the same pressure, like we would expect.

but check the same mass / volume 100 feet away where both temperatures are now equal and the mass of air will be the same IF the pressure is the same. the physics we care about: [temperature, pressure, volume] manipulation of those three give these conclusions.