Rotella... is that you again? Haha IYKYK

Whatever happened to "Building out 91 VR-4" for "aggressive street" on stock block TD04 lol

-sent from my Galaxy S22 Ultra

 

This is Leon - not sure who Rotella is. And this my 3rd VR build. One is DR650 on non build endine gen 2 internal. 1 is Executioners 750 on very mildly build(top end). This one is going to be all out.

 

For wicker spooling I like borg Warner efr twin scroll.
Installed a 76/70 in my 7MGTE mk3 soup.
She comes on early creating lots of torque.

Are you doing twin turbo or single?

Bahahaaaaa…. Wicker.

 

first question, how much power do you want to make. that matters. otherwise you can get little t25 td05's from a 2g dsm that make jack shit for HP but is small and will spool fast

 

Would like to be north of 600wp on 93 - and closer to 700+ on E85

 

good ole MHI evo3 16g's if you can find them. otherwise FP 68HTA with the 51S UHF turbine... DSM 6851S aka 68HTA V3 – Forced Performance

if it was max of 5-600whp, I'd say find some cheap, used 14b's.

 

For the sake of being "helpful"... a lot of this was already discussed within the past year. The answers and suggestions have not changed and probably will not in the foreseeable future.

TD04 vs TD05 <<

Can we get some boost curves here? <<

-sent from my Galaxy S22 Ultra

 

I read those threads. They more about TD04. They do not compare much of TD05 amongst themselves. Also spoke with Forced Performance about DSM 6851S

 

Also spoke with Forced Performance about DSM 6851S - they do not spull up any faster than 16G but do provide more on the top. The only question is I dont think I'll be able to use more flow with this bottom

 

Yup. Litterally what I already told you for your goals…”Evo3 16g if you can find them. Otherwise 6861s.”
The end.

and you have a cool device in center console that changes the operating engine rpm at a given mph. It allows you to put the engine rpm in a range that suits the turbocharger. Use it

 

Run em until they die.

 

If these are the original 3sx headers you're gonna have bigger problems if you don't already

 

Being used the headers may already be repaired / strengthened. I have a used set that look pretty good that I will be putting on in the next year or so.

An EVO 6.5 TME addition turbo made 375 at the wheels on pump gas on my old EVO, so I figure two 16G's are probably good for 750ish at the wheels on a VR-4. It also made 411 at the wheels on race gas, I figure you could get the same results (820ish with 2 of them on a VR-4) on E85 if your fuel system is up to it.

Anyway, I am thinking a "big" 16G variant of some kind will meet my goals... I don't know if a few hundred RPM boost threshold improvement is worth the added expense of a ball bearing center section.

Keith

 

In my experience the key to making a TD05's spool more like a TD04's requires more displacement and/or porting your heads. Since you are stating out with a built bottom end I would look into better flowing heads.

 

Yea idc if they're used, if they're the old style they're gonna crack beyond belief regardless

And setups don't work like that homie. 16gs will do around 500 on 93 pump. Full tilt you're 700 or less on race or e

 

Yeah, I was thinking in terms of peak air flow and how that related to power production... theoretically a big 16G flows 36 lbs per min, so should only make around 360 at the crank or 288 at the wheels on a single. I wonder if the TME addition had more flow than a "regular" big 16G? It did have a larger exhaust housing, but I don't know if there were differences in the compressor housing that may have improved flow. Also, I was leaning on it hard, probably well outside of the design flow rate.

Anyway, looking at the "design" specs of the Big 16G you should be able to get between 500 and 600 on pump and as you said, a bit more if you lean on it hard with race gas or ethanol.

I am thinking that dsm6851S specified above would be closer in results on a VR-4 to what I got on my EVO with the TME edition 16G. A pair of dsm6851S would be about $1,000 more expensive than MHI big 16G's, or $1,800 more than nockoff big 16G's.

Later,

Keith

<edit>UPDATE... after some research the EVO VIII 16G compressor wheel is larger and flows significantly more than the "big 16G" from the previous generation cars, closer in performance to an 18G turbo, so the previous post information is irrelevant since nobody has made manifolds to bolt reverse spin rotation turbo's onto the 3KGT's.</edit>
<edit2> others have called the EVO VIII wheel being higher flow than big 16G to be BS... the joy of internet research, what ever you find someone else always says it is wrong!</edit2>

 

evo3 16g flow 42lb/min. 6851s rated at 51lb/min, but are actually using 68HTC wheels now which are mapped to 53lb/min (and there is another speedline that you can run them at ).

It's also not just about choke flow but where you will run them at for PR. a big 16 is mapped to 3.2PR but peak flow is 2.7PR and then drops off after that.


a 2.0l will need less PR to make the same HP as a 1.5l (3.0l divided by 2). Easy math, 100hp per liter NA. So a 2.0l will make 200hp NA (1 PR), 400hp at 2PR, and 500hp at 2.5PR. on the 6851s, that rides the lower part of map and with another speed line, you can see would be ~55% efficient at 50lb/min at 2.5PR. technically doable, but upping the turbo size for that power would be better at the sacrifice of spool.

Now take a 150HP 1.5l (which is extremely optimistic for a 6g since they don't make 300hp NA), but keeping it simple. 150HP at 1PR. 300at 2PR, 375 at 2.5, 450 at 3, 525 at 3.5 PR. so theoretically, 1050hp with two at 3.5 PR (37psi). Maybe with big cams, short runner intake, ported heads, upped compression and some nasty e85 or M1. but on the typically mild 6g72, need to raise the PR to hit that flow. But doesn't matter with a 6851s.

you can do the same exercise for the different 16g, 14b etc options and look at their compressor maps.

next thing to look at is shaft speed. The higher the shaft speed on a PR/flow point, the more the turbine wheel will flow and generally, the more responsive the turbo will be. so if you pick 3 PR and 35lb/min as your operating point and don't intend to run more than that, I'd pick the combo that runs the most shaft speed at that point. (I'm actually going to change my mr2 setup because of this, i'm "lugging" the shaft on my current combo and have more backpressure than if I pick a different compressor wheel and spin that bitch )

 

evo3 16g flow 42lb/min. 6851s rated at 51lb/min, but are actually using 68HTC wheels now which are mapped to 53lb/min (and there is another speedline that you can run them at ).

View attachment 323223

It's also not just about choke flow but where you will run them at for PR. a big 16 is mapped to 3.2PR but peak flow is 2.7PR and then drops off after that.


a 2.0l will need less PR to make the same HP as a 1.5l (3.0l divided by 2). Easy math, 100hp per liter NA. So a 2.0l will make 200hp NA (1 PR), 400hp at 2PR, and 500hp at 2.5PR. on the 6851s, that rides the lower part of map and with another speed line, you can see would be ~55% efficient at 50lb/min at 2.5PR. technically doable, but upping the turbo size for that power would be better at the sacrifice of spool.

Now take a 150HP 1.5l (which is extremely optimistic for a 6g since they don't make 300hp NA), but keeping it simple. 150HP at 1PR. 300at 2PR, 375 at 2.5, 450 at 3, 525 at 3.5 PR. so theoretically, 1050hp with two at 3.5 PR (37psi). Maybe with big cams, short runner intake, ported heads, upped compression and some nasty e85 or M1. but on the typically mild 6g72, need to raise the PR to hit that flow. But doesn't matter with a 6851s.

you can do the same exercise for the different 16g, 14b etc options and look at their compressor maps.

next thing to look at is shaft speed. The higher the shaft speed on a PR/flow point, the more the turbine wheel will flow and generally, the more responsive the turbo will be. so if you pick 3 PR and 35lb/min as your operating point and don't intend to run more than that, I'd pick the combo that runs the most shaft speed at that point. (I'm actually going to change my mr2 setup because of this, i'm "lugging" the shaft on my current combo and have more backpressure than if I pick a different compressor wheel and spin that bitch )

Nice to encounter someone who can do math! It always annoys me when someone can't understand why a turbo made for a 5 liter Ford won't work on their 1.8 liter Mazda engine!

Since the NA 3000GT pumps out 222HP at it's 10:1 compression ratio I think 200 or less for us with our 8:1 compression ratio is more reasonable than 300 wouldn't you say? It also makes the PR math really easy at this point since 2=200 3=300 etc.

I am going to do a crap load of studying my dyno sheets and math and post up some results in another post after this...

Keith

 

One more point, if it’s a pump gas only combo and you want to maximize HP on pump, then efficiency needs to be considered. But with good intercooling and race gas or e85 efficiency isn’t as important and you can undersize and just run the balls off the compressor and let intercooling and fuel do the rest. That’s assuming you want to maximize spool. If it’s a drag car and no turbo rules,,, I would take a different approach

 

I have E85 readily available and have tuned on E85 in the past on my old EVO, so nice spool for street driving combined and being able to lean on it hard for peak HP in short bursts is the plan. I had a GT35R on the EVO and that was not responsive at all compared to the smaller options that were available, and I wished I had gone with a more responsive setup in that car... but the 550 AWHP in a 3000 lb car was pretty nice!

Keith

 

Yeah I was just using simple math for an easy to understand example. FYI, Most race oriented 4g’s on e85 with good cam, intake and exhaust, it works out to 200whp at 1 PR (NA).

A similarly setup 6g should be able to make 300whp NA. But I find that most choke them up with small cans, long runner intake and full exhaust.

 

I plan on a shorter (but not extremely short) intake runner setup mainly to get easy access to the rear bank of spark plugs, lumpy cams, and a 3" cutout valve on the downpipe. Much of this is in the future because I want to build a shop on my land so I actually have a comfortable place to work on the car... I do this as a hobby, otherwise it would actually be cheaper to pay someone to do all the work rather than investing in building the shop, installing a lift etc.

Later,

Keith

 

Also, FYI, I work for FP and Xona. So if you end up wanting twin 6851s. Let me know. I can set up a discount for twins. (Obviously most people buy just one).