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L31 stroker too high compression


slowride

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On a Mustang Dyno you can go from nothing to fully hitting all the load cells of a given EMS system in about 45 minutes if you have a good cooling system and fan on the radiator.

 

Full Throttle Curve should be optimized in about 15 minutes, and the rest of the time is holding at load points. Where the throttle is puts you at the load points so TPS (unless you are using TPS based EFI for some reason like huge cam no MAP below 4000rpms) is pretty much irrelevant. MAP/RPM will set you up.

 

The original 8X8 MS tables were QUICK. In about 20 minutes you were optimized and had better throttle response than stock EMS. The time is in warmup, accel enrichment, decel enrichment, hot restart enrichment, cold to warm curve, decel fuel cut, etc...

 

You can get the car done in an hour on the dyno, but all the tweaks for cold and off-operating temperature smooth operation can take a few hours over the next couple of months of starts from cold...

 

After that, it's SET. Leave it alone!

 

But this thread is just going wild with conjecture. Quantify what you have and stop with the nebulous comments "Big Cam" idling at 950 and lopey? Not even close! Hell, that could be a vacuum leak.

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On a Mustang Dyno you can go from nothing to fully hitting all the load cells of a given EMS system in about 45 minutes if you have a good cooling system and fan on the radiator.

 

Full Throttle Curve should be optimized in about 15 minutes, and the rest of the time is holding at load points. Where the throttle is puts you at the load points so TPS (unless you are using TPS based EFI for some reason like huge cam no MAP below 4000rpms) is pretty much irrelevant. MAP/RPM will set you up.

 

The original 8X8 MS tables were QUICK. In about 20 minutes you were optimized and had better throttle response than stock EMS. The time is in warmup, accel enrichment, decel enrichment, hot restart enrichment, cold to warm curve, decel fuel cut, etc...

 

You can get the car done in an hour on the dyno, but all the tweaks for cold and off-operating temperature smooth operation can take a few hours over the next couple of months of starts from cold...

 

After that, it's SET. Leave it alone!

 

But this thread is just going wild with conjecture. Quantify what you have and stop with the nebulous comments "Big Cam" idling at 950 and lopey? Not even close! Hell, that could be a vacuum leak.

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For pete's sake - you are chasing the end game w/o knowing what got you there. You said: "I do remember the AFRs being awfully high at WOT"

What were the AFR's? What is "awfully high"? 10:1 is fine for CR - and you shouldn't need to lower the CR just because - that may not be the issue. I have a 3.1 with 11:1 and run 93 octane. Timing is a factor, quality of gas, FUELING, etc..

Stop trying to tear apart your car before you figure out WHY it is pinging or running high AFR's - if it even pinging is at all. If there is no pinging - just very high AFR's, fix the fueling.

Lots of good advice in this thread - take your dyno printout with the AFR's listed and post it here. Or just tell us what it was in the mid-higher RPM range. Mid 12's would be fine. Above 13's and you are working lean - and that can burn valves and pistons/etc..

You,(and us), need more information before you go tearing apart your new motor- that RUNS.

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thanks for all the advice, I hear you guys loud and clear

 

as i said, I bought this project car not running and am just trying to get all the kinks out.

 

Again thanks for all the advice, once I get all the info you guys requested I will post it here. I am in the process of figuring out what crank, rods, pistons, head, and head gasket are currently on the motor.

 

Thanks

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mvkcy0.jpg

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had the car dynod today...on 94 octane

 

car made 150 @ wheels, roughly 225 at crank....on a mustang dyno. here in BC @ racing greed.,

 

so I have a N42 head,, I can see the stamp on the head.

 

motor was knocking at idle/ low rpm but seems to go away as rpms go higher..

 

Head is being pulled to inspect pistons and pull a rod and measure. Inspecting head to see just how good the port and polish job is! Oil pan is being pulled to fix leak and install new gasket, we will be inspecting crank to see any stamping to determine what I have. We are going to measure cams and determine what cams are in the head. Injectors are being sent out to test flow and determine CC. Still have to check timing.

 

Tuning shop reccomends I dump the sds and get a haltech so they can tweak my ignition, they told me with current SDS they have no way to change ignition and properly tune car.

As i mentioned before my AFR's are way too high. Apparently at cruising speed everything is good, but at WOT I am running so rich that I am depleating all the oil in my cylinders and risk running them dry?

 

once we pull the head and inspect crank I'll report back what I have found and what my stroker is comprised of...

 

I am all ears for comments and your views on everything...

Edited by slowride
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Sounds like you need a tune or something I made 150 at the wheels with a stock junkyard l28 p79/f54 combo out of a 82 280zx all I did was 3 screw SU's, msa header, 2 inch exhaust, fidanza flywheel and tuning the ignition and SU's and my torque line was 150ft/lbs from 2500 to 5500 and was about as flat as it gets, stock cam too. This was on a mustang dyno at 6500 feet and known as one of the lower reading dyno's in town.

 

You sure you have a stroker? for a L31 you would need 89 mm pistons and a V07 crank I believe, what about cam specs?

Edited by 19762802+2
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i am not sure that I have a stroker,, I was told it was one by the PO. I am going to find out by the weeks end !

 

If you read my post, you would have found out that I attempted to get it tuned, but with my SDS the tuner was unable to tune my ignition. With my current setup, I am unable to properly tune it.

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I don't understand why the A/F ratio is so awful, or why your tuner cannot deal with SDS, it's a flexible engine management system that should have good control over the fueling.

 

What I'm trying to say is there is no obvious reason why you should have to switch engine management. What you have should be tunable unless it's broken.

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I don't understand why the A/F ratio is so awful, or why your tuner cannot deal with SDS, it's a flexible engine management system that should have good control over the fueling.

 

What I'm trying to say is there is no obvious reason why you should have to switch engine management. What you have should be tunable unless it's broken.

Agreed. My carbs have a better AFR traceline than that. Sounds like your "tuner" is not very competent.

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Agreed. My carbs have a better AFR traceline than that. Sounds like your "tuner" is not very competent.

 

hmm well this is the second tuning shop that has told me this

 

so is it just them? or are they right? they are telling me my SDS cannot control my ignition. both tuning shops have told me the exact same thing! frustrating? **** yes

 

i just spoke with SDS, and I can convert my car to coil ignition system and control my ignition? my current sds has no system to modify my ignition.

Edited by slowride
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hmm well this is the second tuning shop that has told me this

 

so is it just them? or are they right? they are telling me my SDS cannot control my ignition. both tuning shops have told me the exact same thing! frustrating? **** yes

We're not talking about ignition, but about the fuel map. I don't know whether or not your SDS controls the ignition on your car.

 

Frankly, the information in this thread is vague and porous, there are a lot of holes to be filled. What kind of ignition system are you using? Distributor? Crank trigger?

 

The fuel map should be tuned first, followed by ignition.

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I can understand from a tuning shop's perspective why they want you to convert to haltech, but in all honesty, you'll be better off finding a shop that confident enough in their tuning abilities to tune what you have, not what they're used to.

 

Even if the SDS you have can't be utilized to tune the ignition, you really don't NEED to unless you're running a pretty radical setup. An OEM dizzy should do fine to 200whp and beyond. Can you gain more power with programmable ignition? Yes. Is it worth it? Depends on your wallet. For me, an extra 5% or less even hardly seems worth 2k+ EFI swap.

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I am using a stock distributor with a MSD blaster coil

 

How would I go about tuning the fuel maps?

 

Racing Greed told me that with my setup, I can either have cruisng setup or WOT, not both. Currently my cruising is good, but when WOT, my AFR's are way too high.

 

I am trying to figure this out and have come here to try and seek some answers. Please stop posting how I need more info when I have posted that I am getting all the info requested and and posting it as I find out.

 

I appreciate the help, but please read what I have posted before telling me that you need more info. For the fifth time, I am getting all the info that people have requested on the site!!!!!

Edited by slowride
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What model SDS ECU do you have? Garrett on this very site runs 400+whp on his SDS and has reported zero cruise issues, and he daily drives his S30, and brings it to the track on a regular basis.

 

Any ecu with an adjustable map parameter should be able to have a good cruise AND WOT tune. The only way this isn't possible is if the ECU isn't tunable, which SDS is....

 

And again, OEM dizzy + MSD is fine for moderate street goals, and should perform fine under WOT all the way up to 7k and a bit beyond. It won't be extremely stable at the top of the RPM range, but it should get the job done without blowing anything up if your AFRs are close enough.

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Ok, basically your tuner is a doof. If he can't tune the fuel map better than that, he's not trying.

 

You should see 13 to 13.5 AFRs under full throttle, dipping to maybe 12 or so at peak torque. Above peak torque, you can dial back the fuel to 13.5-14 and see no issues, and actually can pick up some power. Cruise and part throttle should see 13.5-14.5 AFRs, with leaner cruise AFR's (I've run upto 15.5 with NO problems) for fuel economy in high vacuum/low load portions of the map.

 

Timing curve, assuming you're running a stock VR dizzy and the factory timing curve (it is possible to recurve these, and it might have been done at some point!) is fixed, unless you have the distributor recurved. I've fiddled with doing it, but don't have the machines to do it correctly. The dyno shop doesn't need to mess with it until they get your fuel curve straight...and if they can't do that then it's time to find another shop.

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Wrote this while Xnke posted, still relevant I think:

 

Here's a few links for those wondering -

 

http://www.sdsefi.com/

 

http://www.racinggreed.com/index.php?section=profile

 

For nomenclature consistency - I think that high AFR means lean, does it not? Low AFR means rich. Your AFRs are low, not high, by your charts, which should be a problem at cruising, not WOT. Air to Fuel Ratio, more air = lean, and vice versa. Maybe by "setup" the Racing Greed guy meant that your injectors are too big to control. Still seems like there would be a middle ground to get good cruising and good open throttle perfromance. Not clear why Racing Greed can't help, their web site implies that they can. But their web site doesn't really show a lot of experience either, just a dyno and some tools.

 

I'm no expert and could be totally off-base, just trying to help with communications.

 

Here's a Wikipedia link just to add a little more - http://en.wikipedia.org/wiki/Air%E2%80%93fuel_ratio

Edited by NewZed
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I have a EM-5D which does not control my ignition. From my understanding the SDS does not allow maps ( or the one that I have does not), its basically one setting for your whole powerband, and with mysetup its not working. Racing Greed told me that its either I have good cruising AFR or WOT afrs; its either one or the other. If I upgrade to SDS coils, I will not be able to properly tune my ITB's because SDS does not support tuning by TPS value?

 

Knocking at lower RPMs and pinging was also heard.

 

Racing Greed's answer is the exact same answer that another reputable tuner shop here in BC has told me last year, when I had the car dyno'd. Racing Greed also told me if I want to have a good tune with my ITB's that the Haltech will allow me to tune via TPS value and Alpha N tuning? Which my SDS cannot do, according to them.

 

I am still in the process of getting the rest of the info that you guys requested.

 

When you guys look at my AFR's from that dyno pull what does it tell you? My AFR's are no where near you guys say they have to be at higher RPM..so how do I correct this? It seems that I need a standalone with adjustability to add or remove fuel and spark at certian RPMS to tune out this and correct this? I am seeing AFR's between 9 and 10 at higher RPM....

Edited by slowride
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Directly pulled from SDS's website here:

 

http://www.sdsefi.com/specific.html

 

Adjustable Parameters

  • RPM - every 250
  • Manifold pressure - 64 locations
  • Water temperature - 32 locations

 

 

That's a 64 cell map for tuning AFRs to manifold pressure. Getting ITBs to run on speed density IS possible, it just requires having a "vacuum tank" or whatever you want to call it. Basically you just need a small box that's fed a line from one (or all) of your ITB(s) between the throttle and valve as a vacuum reference for the MAP sensor. IN FACT, according to extrudabody's website, their datsun ITB kit HAS a vacuum log on it already.... I honestly don't see the issue here.

 

SDS also has accelleration tuning adjustment which should be able to be tuned for your runner length from TB to valve to ensure you don't have any lag as the vacuum catches up with TP movement. You will need to hook up a TPS, but honestly that isn't very hard, and should be doable by any reputable shop. And you'll need a TPS with either speed density (SDS) or a TPS Alpha N blend.

 

Again, this might just be me, but it sounds like you are finding shops that are really good at what they do, but don't want to play in the pool outside of their experience. We're trying our best to help, and I can honestly say that this board is full of people that are DOERS and HAVE DONE. We're not a bunch of guys that only ever learned how to bench race.

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I had a SDS system on my turbocharged Acura Legend that I'll be putting on my Z in the near future. When I had it running on the Legend, everything was adjustable. I have to ask if you have the controller? post-12144-059189100 1333034199_thumb.jpg

 

It's really easy to use. To adjust your AFR, you would go into the RPM fuel section on the controller, reference your dyno AFR map and use the -1 button to subtract fuel at any given RPM until you are reading AFR's where you want them. The manifold pressure settings are pre-programmed from the factory, IIRC, but are also adjustable. These would affect your cruise vs. WOT numbers, so them saying it is one way or the other is crap.

 

You should have full tuneability for your fuel maps. Like stated above, the ignition contol is nice but not mandatory.

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