Boosted lt1, high compression and timing

[anniversaryss]

Currently running a Dual intercooler D1SC. I've hit 13psi on the dyno with mild tuning.
The bottom end is forged but not specific to boost.
I'm pretty sure the tuner was being very conservative and he also tunes ls1 engines so I'm sure that has some weight.

When boost starts its around 19 degrees of timing and up top it's at 14degrees. 10.5 AFR.

We gained some power going to 11.5 afr. But kinda disappointed.

I run stepped headers and 2OTL. He claims the exhaust is choking the car. It could be a restriction but I've seen single 3" muffler car pushing well over 500 wheel hp.

I believe a lot is lost is lost not only in AFR but also timing.

What do we typically run timing wise for 13psi of boost? Also mention I'm on 11 to 1 compression.

I really feel like the car would like more timing and thats where I'm missing my power output.

I've read people say 17-20 degrees sometimes more.

I dont mind flying close to the sun as they say but also dont want to get burned yet.

Also need to mention I'm set up for e85 as well.

So In short what type of timing should I consider with my set up with and without e85.

Thank you
Bobby

[shownomercy]

I have a 9.5 scr 383ci on 93 pump that I run 15psi at 19* with 11.5afr

Its an auto so dyno numbers are meh, 571-658rwhp area depending on type of dyno.

[Z28pr0jekt]

Just be aware that nomercy being at 9.5 versus yours being at 11 CR is a significant difference in terms of boost/timing tolerances.

[anniversaryss]

Z28 I understand thank you. My buddy said evey 1 compression difference is like 1 psi of boost.

From research I believe the car can take 17-19° over 14°.

3-5° would yield the results I was expecting vs what i got.

I've done NA tunes and some nitrous but boosted is new to me so I'm more researching before I turn it up.

Thank you

[Z28pr0jekt]

MoeHorsePower You still around to give a high level input to him? I'd pull up the tune you helped me reconfigure but I don't have access to that laptop anymore. I don't recall the timing curve because it was so long ago but I remember you telling me that the base tune I was given by another company had WAY too much timing in it.

[JOATMON]

How much HP is it making and how much were you expecting, you didn't say. Just curious.
Nolan

[anniversaryss]

JOATMON I copy pasted my original post from another post I made and yes I forgot that information there as well lol

Car made 400rwhp. I was expecting at the least 500rwhp on 93 even with the 3" catback having some restriction (might do a cutout).

The car is mechanically sound, unfortunately we had to stop tuning bc of an oil issue but even so the tuner was very reluctant to add anymore timing. He does LS cars so I'm sure he made some basis of tuning the timing off that as well. Even tho the bottom end wasnt build specifically for boost bc I never thought I would ever go boost it still has forged parts but I know theres more to it when it comes down to aspects like rings etc.

[Z28pr0jekt]

JOATMON I copy pasted my original post from another post I made and yes I forgot that information there as well lol

Car made 400rwhp. I was expecting at the least 500rwhp on 93 even with the 3" catback having some restriction (might do a cutout).

The car is mechanically sound, unfortunately we had to stop tuning bc of an oil issue but even so the tuner was very reluctant to add anymore timing. He does LS cars so I'm sure he made some basis of tuning the timing off that as well. Even tho the bottom end wasnt build specifically for boost bc I never thought I would ever go boost it still has forged parts but I know theres more to it when it comes down to aspects like rings etc.

Are you stock heads/cam/intake manifold? If so, there is a lot of power left on the table there. Personal opinion but 10.5 AFR is really rich to me, even for boosted.

[MoeHorsePower]

When boost starts its around 19 degrees of timing and up top it's at 14degrees. 10.5 AFR.
At what RPM? what the torque at that RPM

We gained some power going to 11.5 afr. But kinda disappointed.
You can run .77 to .80 Lambda on E, but remember, just because you are running E doesnt mean you can turn up the timing, Ive seen cars make 20+ HP on E and some that made none.

I run stepped headers and 2OTL. He claims the exhaust is choking the car. It could be a restriction but I've seen single 3" muffler car pushing well over 500 wheel hp.
I made 722 WHP on a 3" exhaust

I believe a lot is lost is lost not only in AFR but also timing.

What do we typically run timing wise for 13psi of boost? Also mention I'm on 11 to 1 compression.
On a low compression motor, usually around 20 to 21 degrees of timing, with your compression, Id run 18-19 degrees

I've read people say 17-20 degrees sometimes more.
Its always better to run more boost than timing but in your case, more boost will eventually run into ring butting.

Clearances make all the difference, those that get away with more timing could mean there is more clearance between the piston and cylinder walls.

I would pull the plugs at peak torque and see what they read then go from there, take baby steps.

[anniversaryss]

MoeHorsePower

I don't have the dyno graph unfortunately but from some logs I have on hptuners it typically enters boost around 2800-3000rpm. Up around 5800 I'm at 10.6 psi so around 6500 is where I assume I hit 13psi. As for how much torque im unsure as well.

I haven't introduced E to the system yet. Running of 93 at the moment. But I am set up for flex.

722 on a 3" exhaust is great news for me. Good to hear. Alleviates some stress about the set up. Not that its optimal. I went back to the 2OTL bc it originally came on the car and I liked it. I also wanted to tone it down.

As far as timing goes 18-19° is where I figured I'd stop adding timing. I've heard and seen people make quite a bit if power of a few degrees of timing.
Maybe that 4-5 degrees is where I'm losing the power. I've had my suspicion and that's what brings me here.

I have no plans on running more than 13psi. Honestly I was looking at 10-11 but they shipped me the wrong pulley and I went with it.

Plug reading is somthing I need to do. I understand completely. The weather is kinda sucky and my season is coming to an end unfortunately so I'm kinda in the information gathering state right now.

[Z28pr0jekt]

Still looking for more detail on your top end setup, especially knowing now that you're spinning it to 6500rpm. That is not an area stock topend will really handle well between flow capability and valve springs.

[anniversaryss]

TFS 21° 180 heads ported by lloyd elliot.
He said 215cc at 295/230 flow.

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Cam is 223/235 114lsa

[Z28pr0jekt]

Okay so yea, I definitely think your power being lower than expected is at least partially in the tune as you have the top end to support the flow. What size are the stepped headers? I'm assuming they go into 3" collectors into a 3" Y pipe then the 2OTL which necks down to 2.5"? (Am I correct on that?)

Sounds like you get enough fuel considering it's at 10.5 AFR but what injectors? Boost referenced FPR?

You also mentioned dual intercooled supercharger... does it actually have 2 intercoolers? You could have intake restriction if that is the case.

[anniversaryss]

1 3/4 for like 2 inches to 1 7/8 into a 3 inch collector. The exhaust is 3 inch all the way back to the muffler. The muffler exits come out on one side both being what I believe is 2.5. The muffler is a relatively straight though design if that helps. Like I can look into one end and see out the other end.

Fuel is 100% fine. Boost ref yes.

It has the HO intercoolers one on each side. the procharger design. I know a front mount will help a lot but Idk if I want to go that route yet. We did see some high IATs in the 140s a few times.

Intake is a lloyd porting as well with a 58mm holley

[SSlowBoat]

lemme slide in here. we have those heads and a similiar cam from lloyd with the p600b on a 383 and it made more whp, we run ALOT more timing on pump 93 (26-28 total) and were around 12psi.

First thing, your dual intercoolers are choking the hell out of it. we ran the twins for a week and removed them, put an ebay cx racing front mount on and it made less boost (remember boost is just restriction to flow) but more power/that plus the high iat temp is causing the car to go rich. also seems like its tuned too rich/too conservative.

for exhaust reference, cheap summit knockoff pacesetters into a 3" y to a 3.5" mufflex. your exhaust is NOT choking you, your intercooler and also your tune are hindering you

[anniversaryss]

SSlowBoat thank you very much.

I guess I have a lot to think about. I'd like to do a front mount but I'm not all about cutting the bumper.

What would you say would be the max amount of psi you would put through the dual intercoolers?

My goal was only 500 rhp on 93 and use the benefits of E85 after.

[anniversaryss]

SSlowBoat
MoeHorsePower
Z28pr0jekt

Took a look and seems like my air filter is collapsing in on itself. That would be quite a restriction right? As the words my tuner used were "somethings choking it" comes to mind.

What's do you think?

[Z28pr0jekt]

Filter collapsing could definitely be a restriction and could be due to a couple things, old filter falling apart or your filter cannot flow enough air/clogged so it collapses while trying to get the air through. If it is really bad, you may end up seeing a noticeable shift in AFR simply with a new filter.

[JOATMON]

Interesting reading, thanks for keeping the forum active. I'm still an LTX owner and fan.
I don't have any blower experience to contribute, just old timer hotrod experience.
Sounds like your expectations are pretty close at 500+RWHP.
I'm thinking if it's a 350 with the cam and heads you described you're about 425 NA X 150% from the blower=637.
Figuring 75-100 hp loss through the drivetrain you still should be over 500 at the wheels.
Just bench racing with ya'll.
Nolan

[shownomercy]

Ditch the filter, or run a large/overkill one.

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Z28pr0jekt
I bough the system 2 years ago but the guy I got it from had it for a few years but never actually ran it. So the filter is old but was never used.

@JOATMAN
Yep 500rwhp on 93 was my goal.

[Z28pr0jekt]

A couple more things in terms of Dyno numbers in general. The type of Dyno as well as SAE v. Standard correction makes a big difference. Also what elevation are you at?

[anniversaryss]

@shownonercy

What do you recommend?
The filter I have now is 4.6 at the base and 7 inches long and I would guess about 3.5 at the cones tip

Brute speed shows another 3.5 inch filter that has a base of 6 inches and length of 9 inches. I'd guess 4.5- 5 inches at the tip

Only other one is a 4 inch opening 9 inches long.

Since this is a road car I would think a filter would be smart?

[anniversaryss]

z28pr0jeck

I honestly dont know the answer to that.

I am pretty much at sea level

[anniversaryss]

Lol in failing at tagging here 😂😂

[Z28pr0jekt]

No worries, just trying to narrow things down. Dynojet vs. mustang dyno v. hub dyno v. mainline dyno will read higher or lower depending on which one it is. Also STD v. SAE correction will read higher or lower.

There are instances where if you're on one of these Dynos with a certain correction type, you could read 50-75whp different for the same exact car. Dynos are good for tuning but all people want to hear are numbers. This is why some dynos are known as "heart breakers." I do think your car should put down more based on the mods you outlined. I would get the fueling up to the lamba numbers Moe mentioned and work on the timing while keeping an eye on any knock as timing is increased as well as replace the air filter with a good flowing one (I used an amsoil one back in the day because I don't like oiled filters).

If you feel you get the fuel/timing on point with a good flowing filter and it still isn't near the numbers you expect, I would keep an eye on IATs and KR. Other than that, I would take the advice above regarding the restriction of the dual intercoolers.

[shownomercy]

@shownonercy

What do you recommend?
The filter I have now is 4.6 at the base and 7 inches long and I would guess about 3.5 at the cones tip

Brute speed shows another 3.5 inch filter that has a base of 6 inches and length of 9 inches. I'd guess 4.5- 5 inches at the tip

Only other one is a 4 inch opening 9 inches long.

Since this is a road car I would think a filter would be smart?

Really depends on what you have room for. I know the SC side slinger stuff gets real tight on space. For ref the blue one is the one on my car. [ Flange ID 4, Top OD 5.25, Element Height 12]

https://i.imgur.com/YQJ0rkZl.jpg

[SSlowBoat]

we use the biggest spectre filter that advanced auto carries LOL

Sent from my SM-S908U using Tapatalk

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shownomercy

Looks like I could try the 6 x 9 with the 3.5 flange with the room I have.
The 7 inch already very close to intercooler but I could angle a slightly larger one. If worse comes to worse I could test without one

[anniversaryss]

SSlowBoat

I took a quick measurement. When I can get under the car again I'm sure I could adjust the plastic section and move the whole filter down to get somthing longer on there.

[Catmaigne]

What brand of filter are you running at the moment? CFM of the filter media is equally as important as size when shopping for these. Popular K&N stuff uses a very restrictive media. The Spectre, AFe, and other diesel stuff moves way more CFM per square inch of media (and also puts more particulate into your motor, but that shouldn't matter much unless you live down a dirt road). I'm currently running the biggest Spectre from the parts store which seems to work and was cheap, but I also made a bracket to prevent the top button from getting sucked in.

[anniversaryss]

Catmaigne

Whatever the filter is that comes with the kit.

[anniversaryss]

Currently street tuning I have seen 14-15 psi. Up to 18° and seems good
I changed to a larger filter and ks7 knock sensor. Getting some gains on timing and afr changes.

[anniversaryss]

Currently street tuning I have seen 14-15 psi. Up to 18° and seems good
I changed to a larger filter and ks7 knock sensor. Getting some gains on timing and afr changes.

Didn't forget about you guys. Just haven't had any real updates.
Car is on E75 rn at 25° and feeling more powerful than ever. Def not that 400hp 14° of timing car it was. .

Based on injector duty cycle and a few other things I'm estimating 800 crank hp or roughly low mid 600s rwhp.