Engine/Transmission (1994 - 1998) Where to set timing on a 98 215 pump?

[boondock]

Going to be bumping the timing this weekend. Was wondering where I should put it to find a happy medium between mpg, smoke, headgasket trouble, future mods, bottom end, top end etc...



Thinking 16-18



In the next year I hope to have 370's or EDMs. B-1 or similar turbo and I will be done at around 500 hp as it get to expensive for my blood from there on out.



More worried about hp then MPG, would like a decent bottom end but more concerned about top end. Also egt decrease is real important, as well as how it will react with future mods.



What would be recommended if I already had the 370's and a larger turbo?



I only want to do it once.



I am leaning towards 17 but would hear to hear the pro's and con's of 15-19 or so.



Thanks, Kurtis

 

[Joseph Donnelly]

Best mileage and good power, 5. 43 mm = 15. 5 deg. You can go higher, but that favors high rpm over normal driving.

 

[JGheen]

I am in the same boat as you there Kurtis. Mr. Donnelly has told it to you straight cuz the higher the timing, the higher the top end HP but at the cost of lower bottom end torque. I am probably not going any higher than 16 when I get my EDMs and B1 soon as I need more bottom end power than top end for my application.

But since we're on this subject, I have been wondering myself about where to set my timing, so can anyone tell me if it is a good or bad idea to just leave my timing @ the stock 13. 5 or should I just go ahead and bump it up to 15-16 while installing my bigger injectors and turbo? I believe it will be much easier to find TDC with the injectors out anyway since I can stick a long t-handle or something down the hole and roll the engine over until I have reached TDC. I can keep the EGTs in check with my right foot even though they will probably sky rocket with leaving the timing @ 13. 5. So what do ya guys think, kill 2 birds with 1 stone and set the timing to 15 or so while the injectors are out or leave the timing alone to keep my serious bottom end torque I will gain with the new bombs?



Thanks! Joe

 

[JGK]

Joe,



My feelings are there are more gains to be had by bumping it up a bit with your mods than you'd loose by leaving it alone. These trucks are geared pretty low in gears 1-3 so I have to wonder what you're doing that requires padding for more torque down low - towing, I presume.



I think you'd find that by bumping up to around 16 degrees you'd like the results and you wouldn't notice much loss down low. A little adjustment of the star wheel will add a little fuel down there to bring back some torque. Of course, if you do this all at once (new turbo, injectors, and timing advance) you'll never know what the timing change alone did for you, but that's the way it goes.



FWIW,

-Jay

 

[JGheen]

I have to wonder what you're doing that requires padding for more torque down low - towing, I presume.



I think you'd find that by bumping up to around 16 degrees you'd like the results and you wouldn't notice much loss down low. A little adjustment of the star wheel will add a little fuel down there to bring back some torque. Of course, if you do this all at once (new turbo, injectors, and timing advance) you'll never know what the timing change alone did for you, but that's the way it goes.



FWIW,

-Jay

Thanks Jay,

I tow somewhat here and there, but mostly it's trying to get the 37" tires moving in the dirt while climbing hills or romping through the mud. Once I get 4. 10 gears in the axles then I wouldn't be so worried about loosing much bottom end, but for now the 3. 54s I need all the low end torque I can get.



I hear ya on the changes and not knowing if I do it all at once, it would be nice to do one change at a time and examine the performance, but it's just too exciting to throw it all in and feel the new found power. Oo.

I may just leave it at 13. 5 for starters and check out everything, then step it up after.



Joe

 

[boondock]

Jay have you got your rig dynoed?



How are you egts with the 40/16? How mcuh did the cam help? And last the 3 manifold?



I am now leaning towards 16. 5 more of a happy medium.



Others chime in please

Thanks

 

[JGK]

Boondock,



I've had it dyno'd many times! As to what the cam did, can't say that I dyno'd it after just that change. Piers said it will add just a few thousandths more lift and a few degrees of additional open time on the valves. He said the main benefits would be a little better low-end spool-up.



Right now the EGTs are pretty manageable. However, when I get on it hard and get it into 5th, the temps will rise steadily up to around 1300, then all of a sudden go right up to 1500+. But I'm doing over 100 when that happens. Not something I do a lot! On a hill (5% grade I think on the one I use as a test hill), once I hit about 90 mph (empty), the temps go over 1300. The turbo is set to dump out the wastegate at about 42 lbs, so I figure its doing that but the ramp on the plate has just added more fuel so the temps go right up.



Can't say what the 3pc manifold did exactly. Been too long. A little better flow, certainly, and no worries about shrinkage and breaking of head tabs where the bolts go through.



The other day I did a little port work on the manifold at both the head side and the turbo side. I also did a little work on the turbo housing itself to better match the manifold/housing flow. That made a noticeable difference. Subtle, but noticeable. Better spool-up and response. In general, I have no issues with spool up on my PDR HX40/16.



Now dyno numbers. The last one, as I remember (last spring), was about 480 hp and about 1015 lb ft. HOWEVER, I heard later that the compensation factor was set a little over-optimistically that day. So based on that and the previous run I'd made a few months earlier, I'd guess it was somewhere around 450 hp and and in the high 900's for torque. That was on a Dyno Jet. Hope to do another one in mid May on the same dyno. Just before pulling the head for o-ringing and some port and flow work. Then I'll dyno again.



-Jay

 

[Forrest Nearing]

I just bumped mine from ~12. 5* to ~16. 5* (guess the previous owner didn't set it right!!!)



I noticed no difference down low...



to be honest, I couldn't really tell a difference up top either, but EGT's are climbing slower.



did clear up a no-load higher RPM stumble I had in lower gears...



Forrest

 

[Green Machine]

15 is good for a stock truck used for towing

16 is good for a mod truck used for everthing

17 is good for a mod truck used for racing

18 is to much for a street truck



With someting like a set of 370's and a turbo I would go with 16. 5 as a max for a street truck used for pulling anything. But your best bet would be 15. 5

I started out at 12 then went to 15 then 16 then 17 then 18. I had a set of 370's and a 35/16. 18 was way to much for a street truck and even 17 was getten up there.

But 16 was good.