Understanding the differences vf52, 18g, 68hta?

I hope this thread isn't annoying. Thinking about more power while I wait for my oil sample so this could all just be a waste of time. But as I think about different turbos I just want some clarifications on the differences between these models. Right now I am thinking between an vf52, an billet 18g, and 68hta. If I do go for a bigger turbo I will be adding ebcs, injectors, pump, and an aftermarket tmic. I may add a bpv.

Is my understanding for the following turbos correct?

The Vf52 is the fastest spooling of the 3 and seems to fall off around 4500 rpms. With the parts I describe I am probably looking at around 290-325 wtq and around 280-300 hp. 18-20 psi is the sweet spot on this turbo.

The bnr 68hta is the second fastest to spool with full boost around 3400 falling off around 5500. The 68hta requires 22-26 psi and is therefore harder on the engine. 325+ wtq- 300+hp on pump gas.

The bnr billet 18g is the slowest to spool with full boost around 3600-4000 and power goes to redline. 325+ wtq 325+ hp. I think 20-22 psi is the sweet spot on this one?

Ideally I'd like a good powerband between 3000-5500. I think the hta68 is it, I'm just concerned about running that much boost. Right now I got a lead on a used good condition bnr 68 with oil line and the option to return it if its not as described for $650. I am very tempted.

Keep in mind I love JMP and would love to have him build me a custom of any of these its just sometimes hard to find cores and can take a while to find one.

You found that one in CO, huh?

Went looking for it on SearchTempest yesterday...

I found a core for less then that but it wasn't why I made this thread.

I've seen charts that show really fast spool of the 18g, but not many. Ive heard that the 68hta is only good on corn and lots of boost but some have run it with less then 19-20 psi with good results on pump. And i've seen most vf52's barely make 300/300, but some outliers beyond that as well. Just curious if my understanding about the turbos mentioned was corect or not.

My first choice would be the 68hta if it I can run it on less boost and pump gas and still break over the 300/300 mark. My second choice would be the 18g if I can get a fast spool out of it. Most of the dynos Ive seen though are pre 2012 and Im not sure if Bryan worked out the issues before or after that. The vf52 comes in third only because i think it might only end up being a half step above what I have now with its earlier fall off and smaller size compared to the other two. If I am going to spend the money on the supporting mods i want to be able to feel it. I've done some reading on ringland failure that suggests that heavy torque early in the rpm range is hardest on the engine. I didnt know that before. It may be an 18g is the best choice because of the later spool in that regard.

I found a core for less then that but it wasn't why I made this thread.

 

I've seen charts that show really fast spool of the 18g, but not many. Ive heard that the 68hta is only good on corn and lots of boost but some have run it with less then 19-20 psi with good results on pump. And i've seen most vf52's barely make 300/300, but some outliers beyond that as well. Just curious if my understanding about the turbos mentioned was corect or not.

 

My first choice would be the 68hta if it I can run it on less boost and pump gas and still break over the 300/300 mark. My second choice would be the 18g if I can get a fast spool out of it. Most of the dynos Ive seen though are pre 2012 and Im not sure if Bryan worked out the issues before or after that. The vf52 comes in third only because i think it might only end up being a half step above what I have now with its earlier fall off and smaller size compared to the other two. If I am going to spend the money on the supporting mods i want to be able to feel it. I've done some reading on ringland failure that suggests that heavy torque early in the rpm range is hardest on the engine. I didnt know that before. It may be an 18g is the best choice because of the later spool in that regard.

The reason I chose a VF52 is that I've scene many cars make 330whp with them and all supporting mods.

The info about it falling in its face before red line and high torque down low causing ring land failure concerns me. You think a header or cross pipe would help both of these issues?

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I don't agree early torque causes the ringland failure. I ran a BNR16G for close to 60,000km without issue. Only when I went up to a billet 18G did I break a piston.

This. The tune is responsible for the majority of ringland failures, one way or the other. Under pressure, I'd imagine the HGs would give before the pistons.

I'm the most OCD tuner out there, weekly LV kind of thing. No knock tolerated here.

Yes, a HG did let go, right at the same time the ring land went.

If anything, too much torque too early will bend a rod. Ring lands usually fail due to knock, though I think pushing boost higher will get them sooner or later. Only luck and tolerances in whether the piston or the gasket fails first.

a good tune and being OCD about the maintenance is how to protect your engine.

I'm running a BNR HTA71 and it's making full boost (~22psi) right before 4k RPM (~3800) and pulls to redline, and I'm putting up ~320whp/345wtq on pump 93 (mustang dyno). however, forged pistons came along with that (cracked ring on piston 4 with the vf40). I was going to go BNR16G but when I learned I had to change out pistons, I went with forged and a bigger turbo.

What kind of dyno are you going to put it on?

You can get 300whp on a dynojet reliably.

You can get 300whp on a Mustang, but it may start to put you into to knocksville if you don't have consistent 93 octane fuel.

I loved my hta68 was a great dd turbo I was running 25psi on 93 and got 318wtq/300whp on a mustang dyno. Ran it for 50k with. No issues

25 psi is more stress on the engine then I want. Are those numbers with any fueling and IC? I think a vf52 will get those numbers with bolt ons also. I'm leaning towards a 52 again so I can give JMP more biz.

25 psi is more stress on the engine then I want. Are those numbers with any fueling and IC? I think a vf52 will get those numbers with bolt ons also. I'm leaning towards a 52 again so I can give JMP more biz.

I think the VF52 with billet wheel from JMP will reach 300/300 fairly easily. The billet wheel "flows 19% more" than stock VF52 so it's more or less a 17G

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Funny thing about billet wheels... noone except the big boys (Garrett or BW) have a map to back up any of these claims.

Well if I compare my billet 46 dyno results to others I have a flat torque which doesn't fall of as quick as others. But thats all I can really compare is the curve itself.

A 19% increase makes the vf52 go from 34 cfm to 40.46 cfm. The td05-18g is rated at 43 cfm, the td05-16g is 37 cfm I think. So 17g is about right.

My guess is I wouldn't plan to see higher than normal torque peak. But I might get a couple hundred rpms more out of it and a flatter torque curve which would be cool.

I know I don't want to be pushing 25 psi for 68. And after paying attention to my driving habits I don't want to have to downshift all the time to hit power like 18g requires. Unfortunately I can't find too many recent 18g experiences. The ones I did find suggest it requires very careful driving to get its potential to balance load, throttle, and spool.

What we also know about billet wheels is that bnr and others are using them for a reason.

Don't get me wrong, I'm also using a billet wheel and love it. The billet 18G I have does 20G numbers for airflow in g/s on a BR9, but that is right at the limit of what the hot side can flow, so that's not a great comparison. You cannot compare flow numbers directly because no two manufacturers use the same standards for ambient pressure, temperature or what the choke point is. Basically, unless you have a test rig, you are making guesses from anecdotal data. It's ricer math.

OTOH I have also tested billet wheels that did worse than the cast MHI items in back to back tests with no other parts changed, despite tweaking the tunes for days.

Again, the VF-40 and 46 turbines are so small there isn't much point pairing a bigger compressor to them. We learned this years ago with the Deadbolt attempt at a VF-40/18G. You must balance turbine and compressor flow for best efficiency and performance. For example, a friend once built a TD04-18G for testing and had me tune it. It was absolutely terrible.. barely made more power than the usual 13T wheel and then only at much reduced timing. EGBP was so high it could not scavenge properly at anything over 1 bar.

 

The bnr 68hta is the second fastest to spool with full boost around 3400 falling off around 5500. The 68hta requires 22-26 psi and is therefore harder on the engine. 325+ wtq- 300+hp on pump gas.

Apologize for bumping an old thread, however, just saw it.

I've FP 68hta at 19psi that hits full boost at 4000 and stays there to 7000. 310/335 tq. Hit a max of 369 tq @ 21psi before turning it down. All supporting mods were done, tho.