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Discussion Starter #1
04 GT stock motor.

Need some tuning advice. I'm unsure of these mod engines timing curves. Im completely at home with the winsor 302 based motors but not these modulars.

Looking for some real world feedback on your guys total timing in the 10# to 15# boost range on 93 pump gas. Intercooled and non intercooler is fine, just looking to get an idea of these engines thresholds.

Currently mine is hitting about 14# of boost and I'm pulling timing back to 12*. Car is Holley tuned.keeping my AF fairly rich at 11:1.

If this was a fox stock block & aluminum heads,I know I could get away with about 16-18* total timing depending on the whole combo.

Thanks guys
 

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I've had several different tunes, cams, fuel and I run ported PI heads. We dyno tuned it until we were losing power and the below was the max timing we could use that didn't lose power:

91 Oct/meth inj = 11* total
E85/meth inj = 14.5* total

Once we switched to E85 we were hoping to bump the timing up a lot more but lost power with any more.
ks
 

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Discussion Starter #3
Awesome kevin. How much boost were you peaking at, and what rpm were you spinning to? Also, were you intercooled other than chemically?That's good feedback. Makes me question my 12* timing without meth.
 

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Awesome kevin. How much boost were you peaking at, and what rpm were you spinning to? Also, were you intercooled other than chemically?That's good feedback. Makes me question my 12* timing without meth.
We started tuning with 7* and went up from there.
Yes, car also uses a large IC along with the meth inj.
All runs are through full length 2 1/2" exhaust.

Boost on the 91/meth was 19psi through manual trans = 720hp max rpm 6500ish?

Boost on the 91/meth was 25psi through auto trans = 700hp max rpm 6500ish? We had fuel distribution issues so stopped at 700hp.

Boost - 1 on E85/meth was 15psi through auto trans (new cams) = 840hp max rpm 6200
Boost - 2 on E85/meth was 32psi through auto trans (new cams) = 902hp max rpm 6200


We tried everything to add more timing but no matter what we did the engine just didn't like it so we obviously just tuned it for max power.

IMPORTANT NOTE:
I also run a Safeguard Knock Detector which monitors knock in each cylinder. When running straight 91oct (no meth) the knock detector lit up like a xmas tree at only 7psi of boost. In other words: If you don't have a knock detector you could be detonating the sht out of the motor.

I run several key electronics to monitor the engine to make sure it stays safe and, IMO, they are absolutely required when running pump gas or pump/meth:

1. Safeguard Knock Detector
2. Lean Protection Module with dual widebands


ks
 

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Wow 7*, that's pretty low boost for that much knock. What is the static compression of your motor? How much timing did the engine allow without meth.
9.5:1
Never even attempted to run it w/o meth.

I run several key electronics to monitor the engine to make sure it stays safe and, IMO, they are absolutely required when running pump gas or pump/meth:

1. Safeguard Knock Detector with display gauge
2. Lean Protection Module with dual widebands

ks
 

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Discussion Starter #7
Yea I agree. Probably a good investment. Blown HGS is a mofo alone, let alone broken rotating assembly.

I need to invest in Holleys knock sensor add on. Thanks for the info man.

Btw, your Outlaw LCA's are awesome man. Car dosnt spin on the street even in first gear. Just digs, even with 21# in the MT DRs.
 

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Discussion Starter #9
Just the stock PI heads. What's your opinion between PIs and TFS?

My plan to build the short block is pretty straight forward, but I'm undecided porting the PIs, or going with the TFS heads.
 

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Just the stock PI heads. What's your opinion between PIs and TFS?

My plan to build the short block is pretty straight forward, but I'm undecided porting the PIs, or going with the TFS heads.
I don't have any experience comparing the two and I only have concerns on the TFS heads that I read a long time ago about them requiring special cams. A local Mod Motor engine builder tried the TFS heads on his turbo car but couldn't make any power with them so he sold it all off.

With that said Y2K02 uses TFS and is running 150mph in the 1/4 so he would be the one to chime in here:

https://forums.corral.net/forums/drag-racing/2373626-tt-2v-diet.html

If you can get cam info from someone that has a successful TFS platform or talk to one of the custom cam gurus here (mine is custom ground) then I would think the TFS would be the way to go for a max effort combo. Personally I wouldn't go TFS for "only" 600hp but if you wanted to push it then I would look into the cost comparison.

My ported PI heads are flowing enough with 32psi that the car makes over 900hp through three mufflers, 2 1/2" exhaust and a 4R70 auto. With a manual trans and open exhaust the dyno #'s would probably be around 1100 to the tires..but this is pure speculation.

Foot Note: I think TFS requires their own v-covers which adds to the cost of them and I think someone mentioned about special gaskets too.. more research is needed..

ks
 

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Are you using a factory iron block or one of those Teksid (spelling) aluminum blocks?
I am using the iron Cobra block and I'm pushing it to it's limit due to the thinner cylinder walls.. It's not as strong as the Teksid but stronger than the WAP block of those years.

ks
 

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I was told by a local engine builder that the stock iron Romeo and or winsor 4.6 blocks can handle 1k flywheel hp. Is accurate?
Flywheel HP? Probably pretty close maybe a bit high but not sure. Once you take into the driveline losses the HP limit is a lot lower. It also depends on what type of power adder. People have split cylinders on this Iron Cobra block with only 500hp with manual trans and blowers but have made more HP using turbos and autos. It also depends on how hard you run it at that peak power level, ie full time drag car or street terror.

There's some smart engineering type people on the below forum that seem to know every detail about the 4.6 blocks and go into great detail about what makes them weak/strong.

Here's one such thread:
https://www.modularfords.com/threads/258485-Why-You-Want-to-Use-Standard-Size-Bores

ks
 

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Tfs heads do require a different cam specific to them, has to do with the valve relation I was told by them. They also do not require any other special parts. All factory covers bolt on the same.
 
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