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Discussion Starter #1
Thanks to everyone for the tuning advice back in February. Since then, the H1 Hummer has had the following updates:
-The conversion shop (Level 7 Motorsports in Marion, IL) buttoned up the inside, hooked up all the AC components, resolved a power steering leak, added a crankcase vent catch, tuned and re-tuned the transmission, and did a bunch of other minor stuff
-I took the truck in for some interior updates (backup camera, touch screen radio, trim over some of the plastic, etc.)
-Tork Tek fuel adjustable overflow valve (great buy!)
-I was able to get the summer top perfected so now it just rolls right up to make a convertible

See the pics in my album. I tried to post all the build shots but maxed out my folder space on this website. Trying to get Level 7 (did the conversion fabrication) to post on their website soon: www.levelsevenmotorsports.com

Back to my current 4BT issue--as I suspected back in February, in 90 degree temps, and summer fuel, my EGTs are soaring. I’ve spent the last three days reading all the threads I could find, tuning the ppump, re-tuning, and wondering what to do next before the wife drives it and says “it’s too slow, you need to sell it” or “why does the EGT gauge stop at 1600?”).

Here are the details on the truck again:
1999 H1 Hummer open top (weighs about 6500lbs)
Pulled the stock 6.5L TD to drop in a 2012 Cummins recon 4BT
Stock 4L80e Transmission (for tuning I have it shifting at 2.2-2.3k RPMs)
Ppump motor with 3K GSK installed
HY35W turbo w/4” exhaust off an 03 CRD Ram (boost line disconnected; wastegate arm extended)
Large intercooler built
Stock injectors, stock valve springs, and stock engine-mounted fuel delivery pump (25psi)
Ppump timing set to 16.5 degrees
AC on for tuning to add load
4” exhaust for 5’ then reducer to 3” to back (have to get over the rear tire on the H1)

First tuning scenario (which worked great in subzero weather on winter fuel):
-#6 fuel plate full forward
-AFC 1/8” from full forward
-Starwheel just about to the complete left of the window
-Smoke screw at stock
-very slow from a stop, no smoke
-lightoff at 30mph, boost to 25psi before max EGTs (boost still rising)
-EGTS soar at lightoff, had to pull pedal at 1400 degrees

Second scenario:
-#6 fuel plate in the middle
-AFC 1/8” from full forward
-Starwheel just about to the complete left of the window
-Smoke screw ½ turn in from stock
-good pull from a dead stop, slight puff of smoke
-lightoff at 60mph, boost to 10psi max, boost floats at 4psi before lightoff
-EGTS climb slowly to over 1400 degrees
-very slow and worthless to drive

*After this I maxed the AFC all the way forward and basically ended up with scenario one again—lightoff at 30mph but EGTs would soar

Third scenario:
-stock fuel plate full forward (max fuel)
-AFC full forward
-Starwheel just about to the complete left of the window (I never changed the Starwheel)
-Smoke screw ½ turn in from stock
-good pull from a dead stop, slight puff of smoke
-lightoff at 40mph, boost to 15psi max at 60mph, boost floats at 3-4psi before lightoff
-EGTS climb slowly to 1300 degrees max
-very slow and worthless to drive

So, I know this is more an art than a science, but I’m really at a loss as to next steps. I can’t find a middle ground between early lightoff with soaring EGTs vs. 40mph lightoff and no power.

Here’s what I’m considering:
1. My #6 plate was a custom home grind from a local guy. Should I invest $200 in a real plate?
2. Should I try the full AFC modification procedure (washer replacement, grind AFC foot)?
3. Should I just try the #6 plate but back fully towards the cab, backoff the Starwheel, and turn up the smoke screw?
4. Do some voodoo with the Starwheel and AFC that I’m current unaware of?
5. Bigger injectors to help the turbo spool faster then go with the stock fuel plate?

Thank you for any tips from those who have tuned before and know the process.
 

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Hmm, I am battling the same tuning demons as you, except I am having the opposite problem. My EGT's are super low. I've never seen my pyro top 850 degrees. My stock plate is full forward, star wheel full forward, smoke screw in a bit and I have only a bit of smoke at WOT. I am certainly lighter than you at about 4500#, but I can certainly get out of the way quick. Couple of things to think about:

1. Is your inter cooler plumbed correctly? (In front of your radiator) Are you running a fan?

2. Where is your intake coming from? Under the hood or a true cold air?

3. Your turbo is not the best choice for a p pump 4bt. Most feel it is not a good match. I have the favorite in mine. (HX30W). Have you thought of downsizing your turbo?

4. From what I've read, you are pretty far on timing. Factory is 11.5 degrees. 16.5 is far without mods from what I understand.

Anyway, just my observations. Good luck.
 

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Your problem is the HY35 turbo.

Find the original HX30, bolt that on, set boost to 20-25psi, borrow an A/F guage and tune for ~18:1 at max power.
Then you can go back and tune the AFC for the best spoolup without smoke.
 

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Discussion Starter #4
Dougal--thanks for the thoughts on the HY, and I know the opinions are mixed, but I've seen quite a few guys on here make the HY work, just wondering what they're doing for pump mods to match. With the 30+ lbs of boost I'm hoping to get (and have already seen with the HY), I just don't think the HX30 will fit my goals. Even if my motor requires larger injectors, different fuel plate, or some other major change to get the fueling needed, given the fabrication required to fit the HY (hours of welding on the compressor and turbine) there's no way I'm pulling that out.

Clhman--thank you for the points. My intercooler is huge and in front (see pics in album) but you're right, the fan is not on all the time and the H1 setup has the intercooler/radiator setup horizontal so airflow is certainly an issue. I'm going to try fan at always-on to see what difference it makes...

As for air intake, that comes from the above-hood snorkel cap (passenger side) into a huge stock airfilter setup, so I feel good there.

What other mods are you referring to regarding the 16.5 degree timing? Injectors? 4k GSK? Valve springs? What do you think would be next for me?

As for yours, that exact situation happens to mine (low power, low EGTs, real low smoke) whenever my AFC is not fully forward. Is your AFC full forward? My understanding is that's where you should begin with the mods, then adjust Starwheel/smoke screw from there.
 

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Ditto on that turbo. On the EGT gauges, they do make them that go above 1600 deg. Must remember aluminum melts at 1221 deg, so if you spend much time in the 1400-1600 zone you're going to have some melted pistons. They do make steel racing pistons for these engines, but you're talking big money. A #6 fuel plate is extremely aggressive for an engine that isn't heavily modified and running twin turbos. As Dougal said, the problem is the turbo. You have all that fuel coming on early and the boost coming late. Engine is making tons of heat but not much power. Also, you don't want to neck down the exhaust on that particular turbo. It has that 4" outlet for a good reason. An HX30W or a Super HX30W will out perform the HY35W on a 4bt, hands down. Normally, your EGT needs to max out around the 1200 zone. Short bursts into the higher range is OK but don't hold it there for any extended time. Also, your timing is on the aggressive side. The magic number for most of the Dodge 6bt guys seems to the 15 deg. Your 16.5 is probably livable.
 

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Discussion Starter #6
Char--thanks for the thoughts. I'm game to go with another fuel plate. With this setup, what would you think would work?

As for the exhaust, I did numerous runs with 4" straight down/out vs. adding the reducer to 3". There was a slight difference (like maybe 50 degrees) based on where the reducer was placed (right at the turbo vs. a couple feet down), but no difference between straight 4" out and a reducer to 3" more than a foot or two down the line.

My original timing adjust was to 15 degrees. Changing to 16.5 resulted in much lower EGTs, better top end power (above 2k rpms) and didn't change lightoff point at all. Only benefit I could see with going back to 15 degrees is to increase 1500-2000 rpm power, but that would only be under boost conditions, right?
 

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Your turbo is your problem man, Many run it cause they tow often, its not a street friendly turbo by any means, sucks you spent time on it, but its the facts bud. IF you want nice boost, Get compounds, HX30W over a HX35W Has been proven time and time again to be wicked fun, Lonno and many others can confirm this. A fuel plate IS A WASTE of money! If you want power, do the cheap AFC mods, and let it go, A fuel plate is a huge waste. AFC mods alone will give you more power and tuning then a stupid plate will, and it will cost you 2 hours work and 1 dollar at a hardware store for washers. I had a HX30W on my engine, got stupid and modded it out to a 54MM billet wheel turbo, was a huge waste of time, Dougal did math for me and confirmed it was a 400 dollar waste of money. Ditch the HY35W and that hummer will make a fool using a HX30W or a Super HX30W then what it was with the HY35W, I would bet money on it. You want power I assume, I would say go Super HX30W, Many guys here get theres to 30PSI super fast, and little smoke, Look em up, one has videos of his build with the Super, for the money, its a sick turbo.
 

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Discussion Starter #8
I appreciate everyone's turbo comments, but like I've said, swapping the turbo is a non-option and I don't want to make this a turbo thread. If what's required to make the turbo work is a new GSK, injectors, or tuning through some process I'm not doing, that's what I'm looking for. Plenty of people have made the HY35 work, I'd like to know what process they've used to tune, or just what generally people do to tune the lightoff speed down while keeping EGTs low.

Thanks guys.
 

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What other mods are you referring to regarding the 16.5 degree timing? Injectors? 4k GSK? Valve springs? What do you think would be next for me?

As for yours, that exact situation happens to mine (low power, low EGTs, real low smoke) whenever my AFC is not fully forward. Is your AFC full forward? My understanding is that's where you should begin with the mods, then adjust Starwheel/smoke screw from there.
My plan is 14 degrees of timing. I have a 3gsk and it leaves me wanting more. I'm going to a 4gsk and valve springs.

My AFC is fully forward. I have not done the AFC mod though.

Maybe you need to think about some injectors to be better suited to your HY.
 

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My plan is 14 degrees of timing. I have a 3gsk and it leaves me wanting more. I'm going to a 4gsk and valve springs.

My AFC is fully forward. I have not done the AFC mod though.

Maybe you need to think about some injectors to be better suited to your HY.
100 bucks for 4k gsk 400 for injectors, 200 dollars more and you paid for a New super hx30w good luck with the hy35, hope you get it to work. Low get with a turbo with no low end boost won't happen, sorry to sound like a a$$ here but no big turbo has good low end and low egt, it can't light fast enough to make clean low egt.
 

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Ryan, I know of no way you can get around the deficiencies of that turbo. Every one who's used it has experienced similar issues. Slow to spool and higher EGT. There just isn't enough exhaust flow on a 4bt to spool it properly. That turbo was popular about 4 or 5 years ago, but began to show it's ugly side. Seemed like it might be the best of all world on a 4bt but it just didn't pan out. One area where bigger isn't better.
 

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X2 ditch the hy. The money spent on injectors will only pour more fuel causing more smoke driving Temps even higher. Did I not see a thread on what turbo not to use on a 4bt? Guys here know. If you choose not to install the turbo then you will have to live with a lame running truck. Period. A 700 dollar investment will not be regretted. .
 

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I appreciate everyone's turbo comments, but like I've said, swapping the turbo is a non-option and I don't want to make this a turbo thread. If what's required to make the turbo work is a new GSK, injectors, or tuning through some process I'm not doing, that's what I'm looking for. Plenty of people have made the HY35 work, I'd like to know what process they've used to tune, or just what generally people do to tune the lightoff speed down while keeping EGTs low.

Thanks guys.
Swapping the turbo is the only way to make this work. I know you don't like that advice. But it's the truth.

Turbos have to be the right size. Bigger is not better. In your case your engine simply doesn't have enough airflow to make that turbo spool early enough. The problem is worse due to the weight of your vehicle. Lighter vehicles can get away with a turbo mismatch better than heavy vehicles.

Can the HX30 do 30 psi? Yes. Provided you've got the right version.

There is no amount of fuel tuning that will help you. You are short on airflow for that turbo. Trying to make it spool with more fuel just results in smoke and high egt. It becomes a hot smokey mess with poor performance and high fuel consumption.
 

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Swapping the turbo is the only way to make this work. I know you don't like that advice. But it's the truth.

Turbos have to be the right size. Bigger is not better. In your case your engine simply doesn't have enough airflow to make that turbo spool early enough. The problem is worse due to the weight of your vehicle. Lighter vehicles can get away with a turbo mismatch better than heavy vehicles.

Can the HX30 do 30 psi? Yes. Provided you've got the right version.

There is no amount of fuel tuning that will help you. You are short on airflow for that turbo. Trying to make it spool with more fuel just results in smoke and high egt. It becomes a hot smokey mess with poor performance and high fuel consumption.
Can the HX30 do 30 psi? Yes. Provided you've got the right version. <Dougals comment, A super HX30W should give you 100% of what your after for the price of all those engine parts you thought on buying, the guys who have ran that turbo, Have loved it.
 

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You can change to a super hx30 by adding one thing to your turbo... An oil adapter on the pressure side of your turbo. Everything else stayed the same when I did my turbo swap and I was seeing 40 psi before my intercooler install.

-vr4oaks
 

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Discussion Starter #17
Jeep--all pics are in the album under my username. Sorry, couldn't load more due to the file size limits. Hopefully Level 7 will post a build page soon.

The turbo issue isn't the price of the turbo it's all the custom metal fab that had to go in so that any turbo could fit. I still have the original HX, so no big deal there, it's the fabrication on the HY that would be much harder and pricier than all the engine parts to just make the HY work.

Again, I don't want to make this a turbo thread. If I want to make the HY work, what's the best plan? Valve springs, 4k GSK, and injectors?
 

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There is no amount of fuel tuning that will help you. You are short on airflow for that turbo. Trying to make it spool with more fuel just results in smoke and high egt. It becomes a hot smokey mess with poor performance and high fuel consumption.

Copied from Dougal.
 
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