Hit the dyno this weekend

ASSISTANCE Forced Induction
1

I hit the dyno this weekend and came home with some very disappointing results. It was on a dyno-dynamics dyno, and I only made 155.7 fwhp. They claim that their type of dyno is the most accurate, but it also reads the lowest of all dynos. A friend with use only made 235whp, compared to 285whp on a dynopacks with less boost.

But anyways, I’m not happy at all with my results or how the car ran. On my wideband that we tuned with the AFR was a solid 11.5ish all across. My logs from theirs show between 10.4 and 10.8 in boost. Boost also spikes to 10.5 psi and drops off to 7.5psi at redline. This won’t be an issue with my new MAP sensor, but was a huge issue that day.

We ended up smoothing out the AFR and adding some timing advance(was very conservative on first run), but they wouldn’t let me back on the dyno due to an oil leak. Looks like we’ll have to try again next spring :sad:

2

aw that sux. From all the LS turbos ive seen at 10lbs everyone is making atleast 220WHP

3

whats your setup? what kinda of turbo? what are u using for fuel management? do u have stock injectors? and u said u made 155 fwhp. Do u mean flywheel hp or were u just swearing and meant 155 facking hp. what was the Wheel hp number like?

4

fwhp=front wheel horsepower

5

What he said. I’m on a 14b, 450cc injectors, uberdata. Through the main part of the powerband I was only logging 7.5 psi, but even at that it’s disappointing.

6

how is your compression? maybe you have a broken ring or a valve leak, something like that…
clutch slipping maybe ?

7

why so rich?..dont know about tuning for boost but are you doing that for detonation? btw. how much compression are you running?

8

What are you talking about? I said that we tuned it for 11.5 on our wideband which is near perfect and safe. But on the wideband we logged with on the dyno it was reading mid 10’s. I’m concerned with which wideband is correct.

And there’s no way the clutch is slipping. I couldn’t make it slip even if I tried. But a compression test is my next step.

9

Nothing wront with 11.5:1. I shoot for around 12-12.5 but 11.5:1 is safer. Most dynos use tailpipe sensors so I would more confident with your own wideband than theirs.

10

That’s where I’m really skeptical. I screw my sensor into a bung in my downpipe which I think it alot more accurate. The dyno used a tailpipe sensor. But I’m also thinking that their wideband is alot better than mine. I’d hate to lean it out based on theirs and have it end up being too lean.

I smoothed it out and added more timing, but wasn’t allowed back on the dyno. This week I have a 3 Bar MAP coming, so I’ll be able to let it spike to 13psi or so and let it settle at 10. Then I want to go visit the local dynojet and see how it compares to the dyno dynamics. The dyno dynamics is an awesome and accurate machine, but nobody else uses it, so I can’t make any comparisons to anybody else on here.

11

Your wideband is definately more accurate.

Why are you spiking? You shouldn’t spike at all. Or is that just where the 14b tops out?

12

I think it’s just the crappy MBC I’m using. I should not have a problem holding 10 psi.

13

This doesn’t seem to make sense to me. If the boost spiked 3 PSI, then you would have an erratic unstable lean condition, which would not give you a solid 11.5:1 AFR, and you would have readings HIGHER than 11.5.
Also, boost spikes are engine KILLERS–they blow ringlands, blow headgaskets, bend connecting rods, melt pistons, etc… THEY ARE NOT GOOD AT ALL.

Also, the 155 hp numbers does not sound right at all. My guess is that something is very very wrong. What are your compression numbers? Have you done a leak down test?
Is you exhaust clogged with something? (Maybe oil clogging up your cat?)
Also, did you have an EGT in the exhaust gas air stream when you dyno’ed it?
Take note if your engine is not making more power while the boost is increasing, but the EGT is rising. (This is on the path to meltdown.)
Also, check your wastegate, and blowoff valve, as well as your boost controller. Try swapping out the boost controller with a buddy, and see if the boost spikes cease.

Also, are you sure you’re getting boost spikes, and not boost creep? Here’s some info from DSMtuners.com, from a very knowledgeable tuner.
Boost Spike vs. Boost Creep | DSMtuners.com

"Since these two terms are very commonly used in describing turbo/engine behavior, yet they are not always understood correctly, I wanted to attempt to clear them up.

People often mix the two up, or even interchange them, when they are in fact two VERY different things.

Boost Spike: Boost spike is when the boost level initially “spikes” up to higher than the preset boost setting, and then quickly settles back down to where it should be. As most people with turbos know, once the boost pressure in the intake starts to rise, the rate at which it rises quickly increases until the pressure is increasing at a phenomenal rate. This means that, if your boost is set at 12 psi, when it reaches that point it will be increasing so quickly that it will go higher than 12 psi and then drop back down once the boost control system can correct it, which is within a half second or so.

Some causes of spike are bad boost controllers (only ball-and spring type MBC’s should be used, and only proven electronic boost controllers should be used), long boost source or wastegate activation hoses, and the lack of any boost controller at all. It’s basicially an effect a t slow response time of the boost control system.

Boost Creep: While boost creep also refers to an unwanted rise in manifold pressure, its cause and effect are totally different from those of spike, as is the way it manifests itself.

As you know, boost pressure is controlled by the wastegate, which allows exhaust gasses to bypass the turbine wheel. In effect, it creates an alternate route for the hot exhaust coming out of the motor to take, which means that any gas passing through it will not spin the turbine wheel.

Now, if this wastegate cannot flow enough to bypass the required amount of exhaust, then that means that too much of the gasses are going to go through the turbine wheel, meaning that it will have too much energy imparted on it (it will be spinning too fast). As the excess exhaust gas amount gets greater and greater, the turbine wheel spins faster and faster, and the boost level rises.

Creep happens ANY time when the wastegate cannot bypass enough exhaust gas to keep the boost under control. This can happen when the wastegate is too small in diameter, or when the design of the wastegate doesn’t allow it to open enough, or when the wastegate simply doesn’t have a good enough flow path to divert a lot of exhaust. It can also happen when you increase the amount of exhaust coming out of a motor (running more boost/airflow, making more power).

Since this tends to get worse and worse as the engine speed rises (more cycles per second is more conducive to more exhaust gas, to a point), that means that one will see the boost climb to the preset level on the boost controller, and then it will gradually creep up past that line to a “minimum” given the circumstances.

That minimum can be 2 psi above the set boost level, or it can be over 30 psi, depending on how the wastegate is designed, how big it is, the car’s setup, and more.

It is also important to not that you certainly can have spike AND creep at the same time, which would result in the boost level jumping up, settling to the preset level, and then slowly climbing back up again as you approach redline.

I hope this helps.
Happy boosting

-Andrew

14

archivethis

15

I find it HILARIOUS that you post and link that article, because “that very knowledgeable tuner” is my good friend who help me build the car and tuned the car for me. I’ve read that article 1,000 times.

Anyhow, on the street according to my gauge and my wideband, the spikes weren’t nearly as bad, and the AFR wasn’t getting lean because it is tuned for more boost than it’s running. However, on my logs the spikes were worse than I thought, and the AFR did spike too and go lean, but only into the mid 11’s, since it was logging mid 10’s everywhere else.

The exhaust is not clogged, it’s a brand new resonator and hi-flow cat with no muffler and 2.5". I recently set the preload on the wastegate and pressure tested the whole system, so it’s none of that stuff. The 155hp number has to do with the type of dyno, the fact that I was only running 7.5psi through the powerband, the AFR being rich, and not running as much timing advance as I could have.

EDIT: In addition, coming directly from this very knowledgeable tuner, boost spikes like that will not kill engines. How is spiking to 10 psi going to kill an engine, but running 10psi regularly(like I am trying) not?

16

That’s cool. Before I came back here to G2ic, I was over at DSMtuners.com, and starting exploring the limits of my 4G63t on my AWD 1G DSM. (I detonated my 1G DSM with my 14b turbo with about 15 lbs of boost.)
From what I have experienced, the “DSMWisemen” as they are called, have gathered more experience than ALOT of other passerbys at DSMtuners.
In terms of the boost spikes killing engines, here is a link at H-T of an ITR blowing his engine from a boost spike. He included pics of blown ringlands, and bent connecting rods, etc…
http://honda-tech.com/zerothread?id=1183979

But obviously, if you’ve created the fuel map to run at 10psi at WOT and you run 7 lbs of boost at WOT with a enough fuel to feed 10lbs of boost, then this wouldn’t kill the engine. Although, the proportionality would not be the same.

Do what you like, but IMO, I would be watchful of erratic boost pressures, and take measures to prevent it (i.e., varifying wastegate, etc…), instead of tuning by increasing the cushion of fuel to accomodate the boost spike when/if it occurs.
Also, If you really think that their dynometer is as inaccurate as you claim, perhaps dyno your car on another dyno, without changing any of the settings, and see if the different HP values result.

Good luck with the 14b, I was going to put mine on my B20vtec, but the exhaust turbine housing is cracked.

Happy boosting, and long live the 14b.
-Andrew

17

I don’t know if I typed it wrong or you read it wrong, but their dyno, the dyno dynamics, is the most ACCURATE dyno. It’s numbers are alot lower, usually in the range of 15-20%, but they claim that is the real whp number. However, I plan on hitting a dyno jet soon just so I can compare to what everybody else here is making.

I’m not saying that boost spikes are good by any means, but a spike to 10 psi is not going to hurt the car when that is my targeted boost level. A friend with a turbo g2 has had a few accidental spikes to 25+ psi and is still alive. I’m not saying that it’s safe, but our motors are fairly durable.

That ITR is quite a different situation. To start with, his compression is much higher which is one things going against him. Next, unless he just isn’t stating it, I’m assuming he is on the stock 1.75 bar MAP sensor which only reads to 11.03 psi. That means when he was spiking to 12-14 psi, he was still only getting fuel for ~11psi, therefore creating a very lean AFR.

Atleast I finally have a believe of the 14b on my side. Everybody else around here seems to be against them.

18

It’s interesting how you pointed out that the dyno dynamics dyno is the most accurate, but that it reads low. If it indeed IS the MOST accurate, then I would say that it does not read low, but that ALL other dyno’s read HIGH.

I agree with you on the boost spike situation with your car. If you tune your car to run 10psi, but only run 7psi, the occasional 10psi spike won’t cause any damage–assuming the boost spikes will always be capped at 10 psi.

Yes, the ITR example is a different situation–as all engines will always be different, even if built identically. It’s not uncommon for brand new factory engines to have different static an dynamic compression values, even if they came from the same plant made on the same day, and the self-learning OBD-II ecu’s would adjust the fuel maps differently.
I was using the ITR as an extreme example.

I personally like the compressor maps of the 14b, as it makes the car VERY streetable, and makes the boost very usable. It’s a great road racing turbo, and AutoX turbo. Also, the 14b’s are a dime a dozen, and not as hard to get yor hands on, like a DSM 20G.
Even the 4G63t’s are maxing their 14b’s out to 300WHP, on a parasitic AWD transmission.
(If only my b20 sleeves were a little thicker…)

pcd125, would you mind scanning and posting the dyno run? I’d like to see the AFR, and the HP and torque curves. Maybe that way, I’d get a better understanding of what you mean.

Happy boosting,
-Andrew

19

Here is the power chart, I’ll have the AFR and boost log up sometime tomorrow probably. You completely get my point about the dyno dynamics dyno being accurate, I just worded it differently, and most people get very upset and defensive when you say that their dyno jet numbers are inflated, but that argument is for another time and different thread if necessary.

20

Something is very wrong…your TQ is falling off WAY too early and WAY too fast.

When you’re reading your boost pressures, are you looking at a guage or some other sort of log?

Dyno Danamics may claim a lot of things…but if the operator doesnt have it setup up correctly then it could read all sorts of things (high, low…in between). 155 whp is WAY low on any type of dyno at 7-10psi for an LS motor. Fix your problems before you throw it on a Dynojet.

My guess, is that your turbo is fucked.