Timing on 13 psi of boost.
 

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

Re: Timing on 13 psi of boost.
 

What headers? What is the primary diameter? Should be way over 500 HP and need more than a 3" catback. Try a Mufflex" 4". Other than than, exhaust sounds limiting.

What do the plugs say about the timing? Is it close to detonation?

Re: Timing on 13 psi of boost.
 

XS power stepped headers.
no signs of detonation
Although I have not done a new plug WOT pull as of yet the timing mark on the plugs look as if I could use more timing.

Would a cut out suffice? I rather like my exhaust.

How limiting is it tho? I'm not arguing the fact that its limiting but I've seen multiple setups including one with the same exhaust I have that do close to and over 500hp. So I'm curious

Re: Timing on 13 psi of boost.
 

OK…. If you're happy with your exhaust, and don't think a 3” catback is a problem, there's not much more that I can add. And apparently you don’t have the HP numbers???

Re: Timing on 13 psi of boost.
 

I agreed with you that it was a restriction. I never said it wasnt a problem. All I stated is that i know cars with 3" catbacks and boosted put out over 500rwhp restricted or not.
400rwhp was the last number we got but I will go and say that we had to stop the tuning due to an oil issue. The guy that was tuning it said that the car seemed choked and 3" was restricting. Again as to why I asked you, how restricting are we talking since i know of other cars that have 3" exhaust and put down a lot more? Also the reason why I asked if a cutout would help.
Which also comes to the reason why I'm asking about timing. The tuner was also very cautious about adding anymore more to 14 degrees. Which I can understand and i dont blame him. I've talked to multiple other tuners who said he was being way way cautious and could use more timing and it's a possible reason for the lack of power. Again I dont blame the tuner.

Maybe I'm taking your comment the wrong way but No way, shape or form was I trying to start an argument with you or discredit any information you have to pass on. I know you are knowledgeable and very blunt with your posts as I've see in the past.

Re: Timing on 13 psi of boost.
 

Actually, you didn’t specifically ask me for input, I was just trying to help. Maybe it's just my lack of familiarity with S/C builds. Maybe reading the plugs with nitrous is more important than reading them to optimize a S/C tune. Unfortunately, there are very few others here to help any more. I try to jump in when I see posts with no responses. Hopefully you'll get better help from your similar post on ltxtech.com.

I just don't understand how an engine with 13 PSI boost and all those mods is only making 400 HP at the rear wheels. A heads/cam 355 does that. I was “crew” on George Baxter’s record holding 9.05-second 4,000# 30th SS convertible, but that was 20+ years ago and I was just the suspension guy, and helped pack the chute.

Didn't intend to offend you.

Re: Timing on 13 psi of boost.
 

It's all good man. Thank you for responding. I know these forums are relatively dead but I figured what the hell I'll give it a try.

My buddies LS1 with cam specs a tad bigger than mine and tsp 3" single put down 511 on a semi conservative tune. He has 14 degrees at 10psi. It's my understanding that LT1 like more timing than ls1 cars so I figured I'd start there.
The boosted rollcall sticky in this section also has a car running the same exhaust as mine who claims just a tad under 500 on 8psi at an 8900 DA.
I know dynos are just tools and I'm not chasing numbers per se but 400rwhp on 13psi there is somthing missing. I was expecting at the least 500rwhp. That was my goal on 93 octane. I've seen people with an average gain of about 25hp per 2 degrees and some closer to 50hp per 2 degrees.
Now I never give my 100% but mechanically the car I can say is good so I dont believe I have issues there.

Again thank you for your Input. Whenever i get some time I'll have to throw a fresh set of plugs in and give it a hit.

Weather is changing quick so it may have to be next year 😂

Re: Timing on 13 psi of boost.
 

I think you should be OK with your exhaust setup. A cut out on RKSport mid lengths/no cat/open Borla is worth 15rwhp at the 550ish rwhp level. I run 25 degrees at 15psi and intercooled and meth with 9.6CR. When I was 9:1 CR I ran up to 28 degrees non intercooled with meth. That was at the edge though.

Most guys run mid 20s timing at that boost level but you have 11:1 CR so I understand the low timing. If I was you I'd get an Alkycontrol meth system and run pure meth and run a little more timing. On 94 octane and meth gets you race gas like octane and cools the charges air.

Re: Timing on 13 psi of boost.
 

thank you for the reply. Aslo found my filter is collapsed. think that could have some of the "choking" issue I may have

Re: Timing on 13 psi of boost.
 

I don't think, I know.

Re: Timing on 13 psi of boost.
 

Look at the :related topics" links below this for similar threads on timing.

Re: Timing on 13 psi of boost.
 

these guys are running crazy amounts of timing on their set ups. I'm pretty sure they may be ok with a few runs down the track but I def woildnt want to run that on a daily

Re: Timing on 13 psi of boost.
 

Back in the day 9:1 CR was common so mid 20s timing was fine. You would see built engines at 8.5:1 to 9.5:1.
Your challenge is you are at 11:1 CR. It looks like you had a nitrous setup then bought a blower.
Are you sure your tuner knows you have an LT1 and not an LS setup? with your Torqhead LS tuning? Some tuners see that setup and tune as if it were an LS engine that has different (lower) timing requirements.

Re: Timing on 13 psi of boost.
 

Yessir I was nitrous and then went blower. I understood/understand the idea that its not the best way to go about it but I wanted to just work with what I had at the time and just get the car out.

The tuner is well aware it's an LT1 but I also mentioned he was an ls tuner so that could hold some weight as to why he was reluctant to add more timing. That and being 11:1 compression without proper ring gap etc. But I believe 14° even at 13psi is well below what an lt1 would like or want. Timing does create power and I feel that I could benefit from additional timing at 20° max. But personally I'd prob stick at the suggested 17-18°