Unable to rev past 6000rpm in 3rd, valve float or turbine restriction?

[thelostartof]

Ok so after talking to my machine shop who put my head together I am trying to figure out why my b230 seems to have issues going over 6000pm.

My setup is b230f w/ upgraded rods
2mm larger intake and exhaust valves with yoshifab springs and retainers from the group buy with new seats and light port work
Custom intake manifold (NIW) and custom header with a 38mm tial external WG
HY35CW w/ WG hole welded closed
MS2 running LS coils
I am running 27psi on this setup with 1700cc injectors on E85 with more than enough fuel pumps.
200r4 transmission (nearly same gear ratios as AW71)
3.5" exhaust turbo to tail

AFR's are good under load, injectors are in the 80% DC range at 6000rpm.


So what we have been thinking is that either the 9cm2 (.54) turbine housing is way to small causing some kind of back pressure issues or i am getting some kind of valve float at that rpm. Being that I have the yoshfab springs I am doubing that is the issue. In 2nd gear the car seems to rev out to 6400-6500 (I need to go back and look at the datalog from todays testing) or so and then hit a wall, in 3rd I can stay in it but 6000rpm just seems to be the limit the car can do when in 3rd. In looking at the datalog nothing stands out besides the engine just seems to stop climbing RPM wise. I guess I can see over time how the rate of acceleration of the engine changes. rev limiters in MS are all set to 7100rpm or so, nothing has changed since the old setup on the limiters.


I am trying to get ideas if this turbine housing just seems to small at these power levels(bench racing math puts me around 500+bhp after maxing out the 1000cc injectors on E85) or if valve float with upgraded springs and valves are the cause, I know that the valve train might be a little heavier than stock with the larger valves but not this bad. With my old motor and stock head i could hit 7100pm no issues with the same turbo, and MS setup but that was on a stock head and 8.7:1 CR vs the 9.8:1 and extra head flow from the valves. I have also added 2psi over my old setup. I can tell you that so far this current setup with the healthy short block (higher CR) and big valve head sure feels worlds faster than the old setup. Even 15psi feels light years smoother and faster than 20psi did on the old setup.

I have a GT3582R sitting here that needs a turbine housing so I am thinking I need to just go about getting that thing installed sooner rather than later as I am looking at .82 a/r housings for it just to make sure I have the flow up top.

let me know your thoughts.

[gsellstr]

You should be fine with the spring/valve combo. I'm running old Knox stuff, around #95 seat pressure, seems like Yoshi's are right about the same. The valves are pretty close in weight as well. I've had no issues spinning mine to 6800 at full tilt on either the nice 531 or the bone stock head on there now, and that's with a .63 hot side and 23ish psi.

3 thoughts...

Back the boost down, does it wind out better?
What's your timing like at that point?
What cam are you running and at what timing?

I've found some serious improvements if the timing is a little too hot, things like faster spool, more willing to rev, and smoother.

[thelostartof]

When I turned the boost down to 10psi i get what almost feels like a really soft rev limiter at 6500rpm, see below. FYI these are not set to the same scale of time, this is just to show how it sits and stays flat.

Here is the small clip of the 11psi limit
http://thelostartof.net/2020-02-14_09_modified.msl

Here is the 26psi pass where it just kind of sat at 6000rpm, you can see how it just kind of flat lines after climbing so smooth.

here is the 26psi datalog, these are just those few seconds.
http://thelostartof.net/2020-02-13_20_modified.msl

Timing map



Enem V16T cam right now

[cosbySweater]

Have you tried pulling some timing or fuel?

[lookforjoe]

Have you measured Exhaust backpressure in the manifold? That would give you a good sense of whether the problem is excessive EBP. Can't remember what the ideal IBP/EBP ratio is (besides 1:1 which I've never heard of being achieved in practice), however I did have a similar issue using a 20g with too small a hot side, felt like it went completely flat up top. Measuring EGT's might also be helpful, but EBP seems more relevant.

I added a SS bung in the crotch of manifold & got a dual boost gauge from Hewitt Industries for my current setup.

https://youtu.be/m2-6RsIV974

[gsellstr]

That is a LOT more timing that we are running on Ryan's 230FT on pump or mine on E85. Your 300kpa numbers are about where Ryan's are at 15psi on pump, on a lower compression motor. Try dropping 5* from 200-300kpa and see if that helps.

[Dirty Rick]

His spark numbers are high out of boost as well.

I wonder if his commanded timing matches his actual timing?

It should have been rattling like a big dog....

[cosbySweater]

Originally Posted by gsellstr

That is a LOT more timing that we are running on Ryan's 230FT on pump or mine on E85. Your 300kpa numbers are about where Ryan's are at 15psi on pump, on a lower compression motor. Try dropping 5* from 200-300kpa and see if that helps.

This. I bet it cleans up if you pull timing

[thelostartof]

While timing might be an issue, this is the same map I was running on the older motor without any issues. I was actually running more timing on the old setup and I would rev to 7000rpm just fine. Either way I will see about pulling some timing this week and see what it does. Either way check out this timing map from 3 years ago when I used to rev it out to 7000+ rpm with the same MS parts, same turbo just stock head and 8.7:1 CR. If my timing was to far advanced i would of expected this to cause more issues.


After talking with Josh at yoshifab about the possible float of his springs along with the back pressure of the turbo he did mention that with messing with diesel's he sees that the he351 (same turbine wheel and housing but larger compressor) he sees 3:1 ratios of exhaust backpressure because of how tiny this housing is. While I should throw a guage on it I am also tempted to just get moving on my GT35 and go larger on the exhaust side anyways.

Either way the back pressure thing almost makes more sense right away as if I am really making 500+bhp that is a lot of air for that tiny turbine housing to be trying to keep in place. at 15-16psi it seems to pull much smoother than it does at say 25+psi and it sounds like the exhaust back pressure might be a good reason for it.

[Sjeng]

Although probably not ideal, a lot of DSM guys run he HY35 without issues on 2 bar boost, making 400+ at the wheels.

80% DC on 1700cc/min injectors seems excessive, are you absolutely sure you are not running into some kind of fueling issue?

[eabras]

Did you use the same injectors and fuel pumps on the old setup? I would check if your pumps actually supply enough fuel at those pressure levels (base fuel pressure + boost pressure).

1700cc @ 80% dc is alot of fuel. Even on e85 that would be enough for around 550-600, putting your N/A performance around 200-210hp. Seems kinda high for basicly a stock b230 with slightly larger valves, mild port work, a cam and intake/header.

If I remember correctly my b21 with the same turbo kept the pressure ratio at below 1:1 all the way up to around 5700rpm. But that was a completly different setup (low compression, stock head, v-cam, gasoline, 90+ and only 350whp). That setup is also what made me think about the fuel pumps. I had the same problem before I changed fuel pump. Had a brainfart and thought a walbro 255hp would be more than enough for 350-400hp, but with a high base fuel pressure and high boost pressure the flow from the pump dropped off pretty quick, and the car struggled to rev out to 7000.

[Dirty Rick]

[thelostartof]

Originally Posted by Sjeng

Although probably not ideal, a lot of DSM guys run he HY35 without issues on 2 bar boost, making 400+ at the wheels.

80% DC on 1700cc/min injectors seems excessive, are you absolutely sure you are not running into some kind of fueling issue?

On my old setup I was right around the 400whp area and had zero issues. It was after I added the big valve head that these issues showed up. So while 400whp is one thing but the extra flow from more HP might of been right at the limit of this turbine housing. A big valve ported head should be worth a fair amount of power gain on paper, plus another 1-2psi and then adding the higher compression. That is a good amount extra air flow through that tiny hole.

I was running a 255 intank feeding an 044 inline with 1000cc injectors and I was around 105-110% DC with this current setup until my 044 died taking out the HG. After swapping the HG I upgraded to a DW300 intank feeding a DW350il with the same injectors and DC remained the same. I upgraded to the larger injectors to resolve the DC issue. Since then I bumped up the boost pressure 1-2 psi. I have yet to see any sign that the new pumps cannot keep up. At the sametime I rewired the pumps with direct battery power and ground with 10ga wires running off relays from the stock wiring.


I guess we shall see soon more of what is going on as I am going to try to hit the Dyno this month if I can find the time on my schedule.


Dirty Rick: your timing map looks more advanced than mine at higher boost. Is that a dyno tuned map?

[eabras]

1700cc/min x4 is 408lph. A dw350il can't do more than ~250lph@70 psi.

*edit: according to dw's own spec sheet, the number is 305lph@70psi

https://www.deatschwerks.com/sites/w...ch%20Sheet.pdf

[RvolvoR]

What are you using for a trigger pickup? Are you sure you have ALL protections turned off in MS? What does it feel like when it stops revving? Is it like a hard spark cut? Does it feel like it just hits a wall?

[RvolvoR]

Also, I ran mid 20s for advance at 20 psi on e85 with no issues.

[Mogly]

Maybe you have something weak in the charging system or ignition system.

[thelostartof]

Originally Posted by eabras

1700cc/min x4 is 408lph. A dw350il can't do more than ~250lph@70 psi.

*edit: according to dw's own spec sheet, the number is 305lph@70psi

https://www.deatschwerks.com/sites/w...ch%20Sheet.pdf

My afr's are still in the high 11's at that RPM, even if the pump wasn't able to supply enough fuel shouldn't I see the afr lean out?

Originally Posted by RvolvoR

What are you using for a trigger pickup? Are you sure you have ALL protections turned off in MS? What does it feel like when it stops revving? Is it like a hard spark cut? Does it feel like it just hits a wall?

DSM CAS with the Yoshifab High res disc. the 3rd gear pull doesn't feel like anything, it just doesn't seem to want to rev past that point, the best anology I can give is on say a clogged cat when you can't rev over 4000rpm, there is no noise, no odd sound, the motor just doesn't rev past that point. This is why I really am starting to learn towards the turbine housing issue.

Where would I look for protections in MS?

Originally Posted by Mogly

Maybe you have something weak in the charging system or ignition system.

battery is in the trunk with 0/1 wire from battery to engine block and battery to starter. From there I think i have 4 wire running from the alternator to the starter (0/1). I have 4 wire going from the starter to a 960 fuse box that then feeds more of the normal chassis point points. Alternator is a newer reman Denso 100amp unit. I can check out the datalog from MS but voltage has been fine.

[turbotankshane]

Go with your gut, you know your car and setup better than anyone else. More often than not when I'm searching for answers to these kind of issues I end up going back to my original gut feeling. If you know the turbine is going to be a restriction, it can't hurt to go ahead and address that.

[eabras]

Originally Posted by thelostartof

My afr's are still in the high 11's at that RPM, even if the pump wasn't able to supply enough fuel shouldn't I see the afr lean out?

At a given rpm your engine consumes x amounts of air, and needs y amount of fuel. If your fuelpump can't keep up then the pressure over the injectors is lower than expected, resulting in the injectors having to stay open for a longer time to deliver y amount of fuel. Thats why your afr's might be fine, but the calculated dc might be artificially high. Kinda like if you ran a n/a engine with 300cc@3bar injectors with a 2.5bar fpr, the injectors would no longer spit out 300cc. (yup, I suck at explaining).

Other things that springs to mind:

cam timing (maybe the belt is off a smidge, or the pulleys are not lining up. Maybe the key on the crank pulley is broken etc)

Maybe 80% dc is correct and that little hy is too small

[lookforjoe]

Swap out the hotside and/or turbo. The other stuff you can mess with afterwards, if that doesn't resolve it right off the bat.

[RoadRacer4Life]

If you turn the boost down how well does it rev? Boost pressure can def lower the available spring pressure on an intake valve.

[Sjeng]

80% DC on 1700's DC should be impossible if your fuel pressure is 3 bar relative to MAP.
A HY35 doesn't flow that much air. (you should be at +600hp at this fuel flow)
Something is off.

Are you equipped to log fuel pressure? I am pretty sure something is going on with your fuel supply.

Is your fuel pressure regulator correctly connected to your intake pressure/vac hose?

[Dirty Rick]

Originally Posted by thelostartof

Dirty Rick: your timing map looks more advanced than mine at higher boost. Is that a dyno tuned map?

No and it runs on gas even. Stock turbo pistons and thick head gasket.
If you have corn squeezin's in the tank you can probably run more.
Someone else originally setup the spark table with 2wice as much retard and it cracked the turbo and the exhaust manifold.
With E85 you should not need to pull more timing than gas.
You have seen what I am running, which is the (safe?) recommended 1° per 2# boost

Tape a fuel pressure gauge to the windshield and make sure it's not dropping under load. Fuel pressure should raise with boost.
If not, your injectors are getting smaller with boost. You need to maintain the same differential pressure or injector flow rates will change.

Degree your cam! DO NOT guess, or trust the marks, or out trick yourself playing with it. If you have a turbo cam, install it straight up according to the card. This Elgin 262 cam has a couple of degrees advance ground into it. I'll get you cranking compression numbers to compare if you like. But that is no substitute for actually degreeing the cam. Once you have it zero'd out then you can mess with it, you have to have a base line and you may be way off. This one had worn pulley and worn belt on top of the guesswork someone used when they set it up originally.

I spent a lot of time limiting boost to 20# with a GT3071R .60ar RC750's and a 255 pump with the stock intank.

It did this with an AW71 this last time I drove it!

[RvolvoR]

The turbine housing wouldn't make the car stop or not rev...it would limit the power being made, but not make it not rev.

I think its a trigger pickup issue, some sort of protection set in MS, or (like dirtyrick was saying) you've got some fuel system issues.