Kooks and Trilogy SC

[Rob1559]

Just curious here. Is there anyone out there running a Trilogy SC and Kooks header set up? If so, do these work well together?

[Logan]

Not sure that anyone has done it yet... Based on NA numbers, that would make for a downright scary beast of a machine and would most likely mean a sane person would tend to run less boost on the S/C otherwise I think you'd be running dangerously close to the limit for a stock bottom end.

[Lidio]

I had a MM come to us for a Trilogy install about a month ago that was a local guy who I believe doesn’t watch this forum… any way it already had a complete exhaust with shorty aftermarket headers, not long tubes. The system was 100% 2 ½” from the headers back to the gutted tips with no cats at all and Flo-master 50 delta mufflers. It sounded good but was a little to loud in my opinion for a MM.
Although it did put out about 25 more HP’s at the rear wheels at peak. With 4.10’s in the axle too, it ended up showing 409RWHP not 380ish like all Trilogy kits do on stock MM’s with the 9.5psi of boost the kit is sold with.

This particular MM made just under 9psi too, I think it was about 8.8psi. I simply thought it was because of the less restrictive exhaust that made it make less then 9psi where as they usually show about 9.5 to 9.8psi. Also I found that the bigger the rear gear the less HP they show at the rear wheels too.
It seems to be about 3-4% less with the 4.10’s then with the 3.55’s. So this guys MM would have been in the 420 RWHP range with the 3.55s and if we pullied it to be back up around 9.8psi it would have potentially seen 15 to 20+ more at the rear wheels!!
This is all so far with a base tune that I’ve worked with all year on Trilogy #1, #2 and all the other MM’s that got the Trilogy kit in the last couple of months. This tune has proven to be a very safe and extremely reliable calibration until now when used with 92 octane or better in the gas tank.

I personally on my own MM and customer’s… I like to recommend that the four cats be left in tact and only mess with the cat back part of it. I try not to sound like I’m getting old cause I’ve always liked the quite ones that come on hard even with my Mustangs when I was younger. But I like being able to leave my MM running and idling and standing behind it to talk or load the trunk etc… and not smell that rich, dirty smell that they all do as soon as you get rid of the cats. Also the MM does seem to pick a lot of NVH's (Noise, Vibration, Harshness) over all when the entire exhaust has been changed. Not just more exhaust noise out the rear but more through out the whole car and more buzzing through the car it seemed like to me.



Thanks

[SergntMac]

Originally posted by Lidio
I had a MM come to us for a Trilogy install about a month ago that was a local guy who I believe doesn’t watch this forum… any way it already had a complete exhaust with shorty aftermarket headers, not long tubes. The system was 100% 2 ½” from the headers back to the gutted tips with no cats at all and Flo-master 50 delta mufflers. It sounded good but was a little to loud in my opinion for a MM.
Although it did put out about 25 more HP’s at the rear wheels at peak. With 4.10’s in the axle too, it ended up showing 409RWHP not 380ish like all Trilogy kits do on stock MM’s with the 9.5psi of boost the kit is sold with.

This particular MM made just under 9psi too, I think it was about 8.8psi. I simply thought it was because of the less restrictive exhaust that made it make less then 9psi where as they usually show about 9.5 to 9.8psi. Also I found that the bigger the rear gear the less HP they show at the rear wheels too.
It seems to be about 3-4% less with the 4.10’s then with the 3.55’s. So this guys MM would have been in the 420 RWHP range with the 3.55s and if we pullied it to be back up around 9.8psi it would have potentially seen 15 to 20+ more at the rear wheels!!
This is all so far with a base tune that I’ve worked with all year on Trilogy #1, #2 and all the other MM’s that got the Trilogy kit in the last couple of months. This tune has proven to be a very safe and extremely reliable calibration until now when used with 92 octane or better in the gas tank.

I personally on my own MM and customer’s… I like to recommend that the four cats be left in tact and only mess with the cat back part of it. I try not to sound like I’m getting old cause I’ve always liked the quite ones that come on hard even with my Mustangs when I was younger. But I like being able to leave my MM running and idling and standing behind it to talk or load the trunk etc… and not smell that rich, dirty smell that they all do as soon as you get rid of the cats. Also the MM does seem to pick a lot of NVH's (Noise, Vibration, Harshness) over all when the entire exhaust has been changed. Not just more exhaust noise out the rear but more through out the whole car and more buzzing through the car it seemed like to me. Thanks

Wow...There is a lot about this post I need to absorb. Mostly good stuff, but I am confused too, so, sorry, Lidio, I'm still learning so much about supercharging, some of this doesn't add up to me.

This seems so scientific, lots of "formula" stuff here, yes? Calculations? Slide rule stuff? I think?

Let me think about it more, K? I may have a few questions in a day or two, okay with you? Thanks!

[CRUZTAKER]

I had to read it twice...AND print it!

Thank you Lideo, for such of an on hands definitive reply.

[Brutus]

In ref to lidio's post, I used to have a Super Duty with the V-10 and I recall on the Kenne Bell supercharger for that application he recomended against installing headers. Had something to do with cam overlap and the supercharger working better with some backpressure. I do think it is interesting that this one made more power with less boost. I also think this is less of an issue with centrifugal (spelling?) superchargers as they build boost in proportion to engine rpm's. I will see if I can find that information again.

[stumpy]

I am by no means an expert on super charges but I was under the impression that forced induction benefits, rather requires, a freer flowing exhausts, esp. with nitrous.

However, that probably only helps in respect to HP and not torque. I had a Tbird SC that I put a smaller pulley on, chipped it and opened up the intake. I never touched the exhaust, yet it had awsome low end torque but only ok HP. Could it be that the more restricive exhaust was helping torque at the expense of HP.

Is the LSA theory that the wider LSA and a more free flowing header allows too much exhaust to get sucked back in? Or is it that the new charge is getting spit out the exhaust, given that you've got boost vs. vaccume?

Interesting topic folks, and these are just my rambling thoughts.

[Lidio]

Sorry guys, I tend to throw a lot out all at once some times and it can be interpreted different from what I was thinking or trying to point out.

I will simplify it a little or try to explain my thoughts.

First off the slightly lower boost I mentioned on the MM I referred to may have been other conditions or tolerances other then the fact that it had a bigger more free flowing exhaust. But so far all trilogy cars with the supplied 3.4” blower pulley on my dyno’s boost data logger make right around 9.5 to 9.8psi of boost… several of them so far to date.
This particular car made less then 9psi. Being that so far it’s the only one we’ve seen with a full after market 2 ½” exhaust, I immediately assumed that it (the big exhaust) was the cause of the slightly lower boost. It’s typically known that the more efficient a motor becomes through better breathing for what ever reason; exhaust, heads, etc… if it’s boosted… the boost tends to drop a little. Although because of better cylinder filling, less boost can and will make more power depending on the application.


I hate to always mention referrals with Mustangs but this all applies for the most part.
Here’s a really good example and very typical application at my facility and what a more efficient motor will do to RWHP and boost;

A common ’99 and newer Mustang GT with a 4.6L 2-valve and a Vortech supercharger making 11 psi and absolutely no other mod’s what so ever will put down around 345-355RWHP with a safe tune that wont take out pistons. We recently rapped up a ’99 GT with extensive mods with the same Vortech blower, but it had CNC ported factory ’99 GT Heads, stock cams, Long tube headers with a full 2.5” exhaust, 2 hi-flo cats and a Bullitt intake not the normal 2V GT intake, It also had a “big-bore” short block which bumps the cubes to 305 not 281. When we put it back together we new the new bigger cubed, more efficient heads and exhaust would gobble up some of the boost so we went from a 3.6” pulley to a 3.3”.
In the end it made 420RWHP with a safe tune and the boost was still at only 10psi, not the typical 11 we see on the Vortech set-ups on stock GT’s at 6300rpm’s. This car actually made slightly less boost or absorbed more of the boost because it had a bigger more efficient engine/head set up. And still made significantly more RWHP then a totally stock GT with just a Vortech on it.

In short: a more efficient… better breathing motor will make more power and better use of lets say 8psi of boost then a corked-up less efficient motor. Typical old school hot rodding!


On a different note, trying not to sound contradictive, many people will argue this but it’s a known fact that back pressure in the exhaust typically produces more low end torque and throttle response. We learned this a long time ago when people started to put long tubes and big exhaust on EFI 5.0L trucks and immediately lost gas mileage and noticeable amounts of low end torque.
A lot of people just don’t care, don’t notice it or its not that noticeable because they may have other mods that make up for it, like loose torque converters, bigger rear gears or blower etc… I’m not saying bigger exhaust is a waste of money by any means. But it is known and true that some back pressure helps low end torque. The area (operating range) we drive around in the most.
It’s no mistake or accident that our MM’s have 2” exhaust for a good portion of it,
not 2 ¼” like other performance Ford cars with V-8’s.


Thanks

[Brutus]

Just for S$*#'s and giggles, did the car in question make less lower rpm power than say one with a stock exhaust???

[Kelly]

If I read Lidio right a system like the Kook's header and 2.5 exhaust system might rob the low end, and hurt the cars engine overall more then they help, so stage one period might be a better way to go then stage one and Kook's headers and bolt on kit?

[Logan]

Kelly, that's absolutely false. Overall, the Kook's exhaust will produce even MORE power on a supercharged car than on a N/A car, which it's already producing 50rwhp and 35ft/lbs.

The Kook's by itself produces a ton of low end torque over a stock setup. Like Lidio says, a more efficient exhaust = a more efficient engine.

Regardless, if one is to keep the stock exhaust system on their car and supercharge it, the power band will be decimated past 5200rpm due to the restrictive stock setup.

[Kelly]

I had called Nick allready for the t304 bolt on system, it was Lidio's last statement about their being a reason that the MM's exhaust is the size it is that threw me. Thanks Logan.

[sailsmen]

I am confused, what part of Lidios' statement is related to more stress on the engine?

[Logan]

Well, where the issue potentially is, is that the stock short block can only handle so much power before you end up throwing a rod out the side of the block.

With the kooks on, the supercharged engine is going to make significantly more power than the 385rwhp seen on a completely stock car with stock exhaust.

If you start making TOO much power without going into the short block to upgrade the rods, lower the compression, replace the oil pump gear and possibly upgrade the crank, you risk your motor going south.

These stock short blocks hold up fairly well through about 450rwhp, but I personally wouldn't run more than about 425rwhp without going into the motor for some serious upgrades.

But for me, upgrading the tranny is paramount. These trannies weren't designed to handle 450rwhp. Make much more than 380 and you really should be pulling the tranny apart and bullet-proofing it, which is exactly what I'm doing in a week or so. :)

[Lidio]

Nothing in my reply was referring to engine stress. Only the effects of big exhaust with a blower. Bigger exhaust with any blower and non blower application will make an improvement in horsepower, especially in the high RPM’s. When I refer to a loss in low end torque… I mean very low end, like below 2000 to 3000. This is an area that’s hard to measure on a chassis dyno because of rolling start speeds on the dyno and stall speeds of the torque converter etc... But it can clearly be felt most of the time when just driving around normal. Especially if the car has small rear gears and tight factory type torque converters. They tend to get a little mushier feeling. It’s very noticeably on stick shift cars where you can really bog them down when in the wrong gear at low, low rpm’s.
When long tubes are sized right both in diameter and length, they will improve low-end or at least not hurt low end while improving the high rpm power.

On roots type blower cars like the Trilogy kit… this some times loss in low end is almost completely unnoticed because the roots make lots and lots of boost right off idle. Even when the boost gauge isn’t showing any boost or just zero inches of vacuum. They seem to make the engine feel so much better even at just very light loads and no boost.

On centrifugal type blowers on most of the mustang apps we do, because they don’t make any real boost at low rpm. We go out of our way to make as much low end torque or not sacrifice to much by not lowering compression to much, not over camming the engine, not going to big on ports, valves and intake manifolds.

Yes when the bigger is better rule is applied to most of this, the high rpm HP numbers are great... some times outrages, I’m referring to cars and engines that hover in the 1500 to 4000rpm most of the time on the street from light to light. Believe me I’ve built a lot of mild and wild cars. Big inch motors and little 281’s. They are usually in 2900 to 3300lbs mustangs that are easier to tug around. The MM on average is 4500+lbs with two adults. It’s given me a different look at how we approach hot rodding these cars. That’s why I’ve been behind the trilogy deal from day one. Tons of low-end grunt in a heavy car with a stock torque converter and the 3.55 gears feels very good around town. Not just at WOT at over 5000 rpm’s.

This week I'll try to post some dyno graphs for some comparisons on a trilogy car we did that has the stock boost and only a 4.10 done to it, no other mods, and the one that had the stock pulley or boost and had the complete 2.5" exhaust and also 4.10's


Thanks