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It’s time to formalize the challenge: Let’s get the 03 and 04 SSRs from a 0 to 60 time of 7.6 sec (average weight driver, couple gallons of fuel) under 6 seconds, into the high 5s.

Don’t laugh. My own 04 SSR is 2/3, or more, of the way there as I write this.

A stock 03 or 04 SSR with a 160 lb driver and 2 gallons of fuel can, according to Chevrolet, and actual road tests, do the 0 to 60 in about 7.6 seconds. I weigh more than 160 lb (!) and I don’t run around, or do acceleration testing, with only a couple of gallons of fuel, but rather I test with 14 to 15 gallons since that is more typical of the fuel weight load I normally have aboard. Bone stock, my computer modeling software says that I should run 0 to 60 in about 8.1 seconds.

I have done just 3 things to improve my 0 to 60 times so far:

- Changed the rear axle ratio from 3.73 to 4.56

- Had the SSR tuned after the change using a Dynojet dyno and HP Tuner

- Started shifting the automatic transmission manually on testing runs, shifting at 6000 rpm instead of letting it shift automatically at the factory setting of 5600 (I will get this programmed into the ECU via HP Tuner at my local speed shop in the next few days)

Shortly after doing the gear ratio change, I acquired a G-Tech RR computerized vehicle accelerometer that comes with software that installs on your home computer and provides amazingly detailed data on each and every test run you make. My current results as measured by the G-Tech, with my driver weight of 235 lb and 15 gallons of fuel aboard are 0 to 60 in 6.5 seconds. So I am 2/3 of the way towards the 5s – without getting mechanically inside the engine!! And, remember that that is with me and a bunch of fuel aboard.

I got these results for a total expenditure of about $1500, by using an analytical versus “my buddy says” or “experience says” or “that’ll never work” approach. I analyzed the power curve of the 5.3 liter SSR engine, looked very closely at the transmission gearing, and applied a lot of what I have learned doing similar projects on fast motorcycles (10 second ¼ mile machines with 0 to 60 in well under 3 seconds).

Why do this to a heavyweight (4639 lb) cruiser? Because most hotrodders and all of the auto enthusiast media have made a big mistake in writing off the 5.3Liter SSRs as being incapable of nimble performance. Ironically, this has contributed to the difficulty in selling new leftover SSRs despite attractive pricing, because although GM built a “cruiser”, their advertising, and the styling of the vehicle itself, both imply “hot rod”. I am now certain that I can prove the doubters wrong, and in fact, if I am right, some enterprising dealer or speed shop should buy up all those leftover new 04s, apply some of the the same mods that I have done and will do, and sell them as fairly unique performance vehicles!

My computer modeling software says that to hit the high 5s, I need about 10% more average power being applied than I’ve got right now..

To figure out how to GET that power, it’s time to get even more scientific.

Below is a screen captured from my G-Tech’s PASS software. Note the current “baseline” results achieved early last Sunday morning at that secret straight and level test site which was retroactively discovered to be within a fraction of a mile of a police station (see my recent “I THOUGHT I was alone” posting).

(see image attached below. It IS fully readable if you PRINT it!)

This screen shot displays one of many graphs available in this software: the RPM versus time, for a complete ¼ mile run (and slightly beyond).

This graph has acquired new significance for me since I finished reading John Lingenfelter’s book on building Chevy engines. He shows early in that book how this graph can show you pretty precisely what rpm range to focus your improvement efforts upon. Lingenfelter’s advice is to look at what rpm range your engine is spending most of its time during the run, and optimize the power in that range.

Notice how I have dropped vertical lines onto the graph. These lines divide the entire 1/4 mile run into rpm ranges:

Under 4000 rpm (labeled “<4k” on the graph)
4000 to 5000 rpm (labeled “4k-5k”)
5000 to 6000 rpm (and slightly above 6000) (labeled 5k-6k)

It is VERY interesting to look at how much of the 15.07 seconds of the ¼ mile run were spent in each rpm range:

Under 4000 rpm: 1.6 sec or 11%
4000 – 5000 rpm: 8.0 sec or 53%
5000 – 6000 rpm: 4.1 sec or 27%
Shifting & flywheel / torque converter effects: 1.3 sec or 9%

For the 0 to 60 time (instead of the ¼ mile time breakdown shown above):
Under 4000 rpm: 1.6 sec or 25%
4000 – 5000 rpm: 2.4 sec or 37%
5000 – 6000 rpm: 1.7 sec or 26%
Shifting & flywheel / torque converter effects: 0.8 sec or 12%

Makes it pretty obvious where the efforts on getting more power should be concentrated, doesn’t it? The 4000 to 5000 rpm range should be the priority target, with 2nd priority going to 5000 to 6000 rpm. Spending a lot of time and money on the rpm range below 4000 rpm is not going to help the effort much, since even a 25% increase in power there is going to change the time by only 0.4 sec or thereabouts, which is not enough to get into the 5s, AND:

1. Torque converter effects help us at 2000 rpm or below anyway, and
2. We can achieve MORE time reduction with LESS percentage power improvement in the rpm ranges where most of time is being spent.

Remember, the modeling software says the required power increase to hit high 5s is an AVERAGE of only 10% across the rpm range, and that that power increase would also get us to about 14.7 seconds in the ¼ mile.

As an aside before anyone with a stock SSR gets too excited, remember that the above rpm versus time analysis applies to MY SSR which has been significantly regeared (22.2%!). The time slices are going to be entirely different for a stock SSR, as that crippling stock gearing will drag out the “under 4000 rpm” time slice a LOT, at the expense of mostly the 5000 to 6000 rpm time slices, and a shift at 5600 rpm into 2nd is going to drop the engine way down to 3000 rpm, where it will struggle some more. You’ll need to do your own, different analysis for a stock or differently modified SSR.

BUT, getting back to MY mission to find another 10% average power increase beyond what I have already gotten, very few power increasing methods work that uniformly across the ENTIRE rpm range. A positive displacement screw type engine driven supercharger has that kind of capability (and much greater actually – more like 40% more power!), and is on a dollar per horsepower basis the best “value”, BUT it requires investing ALL the money to do it in one chunk. With a son in college, and too many involuntary simultaneous residences in 3 states right now, coming up with one big chunk like that is not a great idea for me. And vendors don’t offer “easy terms”!

What I AM thinking is some combination of:
- Cold air intake
- Cat-back exhaust
- Headers
- Hi-flow cats

I’m pretty sure that I need some “combination” because no one of these has the potential to make a 10% across the rpm range improvement by itself, despite vendor claims and so-called dyno charts that sometimes imply otherwise.

My need now is very straightforward: I need REAL and RELIABLE “before and after” dyno curves for vehicles with SIMILAR initial states of tune as my SSR has as its starting point. By that, I mean I do NOT want dyno curves that show how a set of headers uncorked an engine and added 40 hp, when the underlying truth is that everything ELSE except headers had been done, and so the exhaust manifold became a “bottleneck” that was preventing the other mods from being fully effective, and so the apparent effect of the headers didn’t just show the results of the headers but rather of ALL the mods!

I am thinking that there are probably a few of you out there who have the same itch as I do here, and so maybe if we all make a concerted effort to find GOOD reports and dyno curves, that describe accurately the effects of ONE of the above potential mods in reasonable isolation, on an engine reasonably similar to our 5.3 liter LM4 engines, we might be able to get to the high5s with a lot less time and money being spent and wasted.

Also, any of you vendors out there monitoring our board: If you have a product that you can back up with a solid guarantee of performance to at least a specified level, let me hear from you. As you can see from the above action and results, I am not just messing around.

So, anyone out there got any solid information they can contribute to this challenge project?

Jim G
[email protected]
 

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coefecient of drag

Jim, looks loke you are pretty detailed.Iv'e made several mods to my 03 but don't have the benefit of software annalysis.
I (so far) installed comp cams 1.85:1 roller rockers w/ studs,plates and hardened push rods,stock K&N air filter,dynatech ceramic coated long tube headers, Magnaflow cat back exhaust,crane cams throttle body spacer and powermax computer tuner.
I don't have an accelerometer or before/after numbers but I bet I'm close to your goal.This thing is a bad ass.I think if I stuck a Yankee torque converter in it,that would complete the upgrade.

Craig
 

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I'd say '53wannabe pretty much has it nailed. 1.85:1 rockers, freeflowing catback, effecient air box, computer tuning and 2800 stall convertor in addition to the 4:56 gears will get you under 6 sec. Full length headers and fiberglass hood are icing on the cake. I don't know all the technical jargon though I am sure it is interesting. Just an old seat of the pants drag racer who knows from experience what better breathing and applied torque will result in. :)
 

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Discussion Starter #5
I'm trying to avoid getting inside the engine at this point, so the 1.85 rockers haven't been in my plans at least yet. Is the principle there as simple as it sounds: lift the valves faster higher without changing the cam?

I don' t think I want a high stall converter, as that would soften the normal (not hard acceleration) driving response. My ideal is an automatic that feels as close as possible to a manual transmission except no clutching required! I value crispness.

The ctback exhaust, AND high flo cats, seem like a good idea, as they are a relatively straightforward install, BUT I want hard dyno data before I spend the money, as I have seen way too many exhaust systems that got the owner nicer sound but insignificant, or no, power increases.

Headers are a tougher install, with lots of potential for troublesome interference and strange vibratory noises. But, if the RIGHT ones are chosen, they can be very effective. Again though, I've seen a lot of installations that got the owner very little extra power, so I need to see hard dyno data before anyone gets my money!

It would be nice if we knew where the WORST stock bottleneck is on our SSRs. Wherever that happens to be, THAT is the mod that would get the biggest bang for the buck. Is it the air intake, the intake manifold, the valves, the exhaust manifold, the cat, or the cat-back exhaust system? The whole idea is to find the worst bottlenecks in priority sequence and enlarge their flow capabilities, so that we move more air and fuel through the engine!

Jim G
 
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Here is what Magnaflow is saying on their cat-back:

http://www.magnaflow.com/02product/dynos/15843.jpg

I don't have my own dyno numbers, but the increase I got feels just like what they show on the chart with no other mods yet, and anyway they guarantee results. A side benefit is my average mpg has been steadily increasing since I put on the exhaust - and this with me romping on it all the time to hear the great sounds. The weather has been too crappy here to get 1/4 mile runs yet - rain and/or high winds almost every day. I'm on the same mission as you btw thanks for the analytical work.
 

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Discussion Starter #7
My research on the (apparently) expensive Dynatech Supermaxx headers brought to light a number of things about them, and all but one being VERY positive:

- The pricing seems high until you remember that these are all stainless, and INCLUDE two hi-flow cats, and a proper y-pipe, and factory type connections where needed to mate with the rest of the exhaust system

- Very good well thought out instructions.

- Easier than average install (one installer commented that it was the easiest header install he had done in 40 years)

- There were both torque and horsepower increases across the rpm spectrum on the 2003 Ram hemi installation I read about, and no dips anywhere.

The negative:

The horsepower increase was only about 17 hp or just a bit more than 6% on that engine's rear wheel power.

However, the article noted that it was a very hot (92 degrees) and humid day. I have seen firsthand how dyno sessions on that kind of day do NOT usually let the engine perform to its normal potential, because although the dyno operator applies correction factors to compensate for the ambient conditions, in reality NO engine responds correctly to adverse ambient condtions, AND most engines will retard their timing under those conditions and load to prevent detonation. So, the dyno results were inconclusive in my book.

I need better data to convince myself that these are the way to go, but since everything else about them looks so good, I will persevere and see if I can find better data.

Jim G
 

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Discussion Starter #8
psychoslaphead: I really wanted to believe those Magnaflow numbers when I saw them on that graph, but I found 3 problems so far:

1. The 20 hp gain is NOT a gain of 20 hp at peak. The 20 hp gain occurs higher in the rpm band than for the stock exhaust, and so it is 20 hp higher than stock THERE, but not 20 hp higher than the stock PEAK. That claim is technically correct, but misleading to the casual reader.

2. Unfotunately, that graph is the exact same graph shonw for 3 other vehicles on their website, and I don't believe that all those vehicles got exactly the same graph results on the dyno! (check it out for yourself)

3. I looked at a few articles by magazines on actual magnaflow installs (other than SSR of course - too few out there for mags to do install articles on SSRs, but saw Ford F150 with 5.4L for example). The actual achieved results did not come up to the Magnaflow claims.

I believe they probaby do provide some extra power, but I want to know HOW MUCH before I spend the $707 plus labor.

I believe the Magnaflow "guarantee" might say you will get more power, but it does NOT guarantee you will get at least the advertised 20 hp gain. That neuters the guarantee in my book.

Jim G
 
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On the 05 :ssr 6.0 liter the dynatech headers and hiflo cats added 31 rwhp to mySSr by a mustang dyno tork was higher at a lower rpm after install. dynoed before and after. when we get the super charger we will know what that added to the rwhp. then I am going to dyno on a drum dyno to see the difference there. I should dyno it now to see what I gained putting on the 3" flowmaster catback exhaust system for the 04's. :thumbs :flag :seeya


I do have a green air filter. that was in before and after also.
 

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Discussion Starter #10
BobA: THAT is good, usable data! THat really encourages me on the Dynatech Supermaxx headers.

The exhaust system numbers would be really interesting too.

You are going to see a notable difference between the Mustang "steady state" electric brake type dyno and the Dynojet inertia drum type dyno. The dynojet numbers are generally a LOT higher - typically 15% higher. This is a result of wildly different operating principles.

The steady state dynos are a more accurate measurement of actual numerical horsepower, and enable far more accurate tuning at both full and partial throttle. The inertia dynos better demonstrate the benefits of reduced moment of inertia within the drivetrain (e.g. lighter flywheels, clutches, wheels, and tires) upon acceleration in a street setting.

The inertia type dyno are grossly fooled by changes in gearing. My SSR dynoed some 20 hp lower immediately after the gearing change than it did immediately before the gearing change, with no other changes, and just as the experienced operator predicted it would. I have in the past found the same sort of effects on my motorcycle projects. Despite my engineering degree, it is not clear to me why this is so. This is why Dynojet operational instructions are very specific about what gear to do the runs in.

If you do a run on a Dynojet with an automatic-transmission-equipped vehicle, and look at the resulting hp versus time graph, you will clearly see that the horsepower curve for 1st gear is lower than the one for 2nd gear which is lower than the one for 3rd gear. Dynojet has never to my knowledge addressed the cause of this gearing effect publicly.

Interestingly, it appears also in all testing I have ever done or seen using computerized solid state accelerometers like the G-Tech RR I use. Of course, with any of the onboard computerized accelerometers like the G-Tech, they are only capable of showing the NET horsepower at the rear wheels AFTER horsepower used to overcome air drag and tire friction, since they base their horsepower calculations upon the net acceleration achieved, after a cetain amount of the available power has been used up overcoming the air drag and tire friction (these losses are of course enturely different than the driveline losses already suffered before the power gets to the rear wheels). The onboad accelerometers do not know the Cd and square feet of frontal area of the vehicle, so they cannot calculate the drag. So, to get the total net rear wheel horsepower, you have to manually add the drag losses to the G-Tech numbers to build the actual rear wheel horsepower curve.

The onboard computers do actually have the ability to determine the drag losses via a coastdown test, but I have only ever found one accelerometer that supported that mode of operation, and it had inferior capabilities in other respects that make it undesirable to use,

Dynamometers and accelerometers are a whole other intereting discussion. :)

Jim G
 

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Jim, I take it that your's is an 04. How much differnece between the LS1 5.3 and LS2 6.0? The 05 0-60 times are around 5.29-5.49. If the difference is cams, heads and throttle body I would think it an easy upgrade. I believe the throttle body inlet on the 04's are 85mm and the 05 has a 90mm. That would probably add to the breathing for the engine.

Also what factor do our tires play in the game of performance? I can understand our fatties on the back for traction but not the front. I would think it requires more hp to turn them than a set of 60s or 70s up front.

Also what about brake rotor size? I saw on I think NOPI TunerVision were they added larger rotors to a car and it decreased the time on the car. So would smaller rotors add any increase in speed?

I do like your style of adding performance to the truck, I'm in the the same boat of add a little at a time. Also not wanting to waste any money on anything that does not show hp gains.

You may want to look into the Throttle Body spacers. Airaid has dyno charts on their site for a 5.3 Tahoe. I have one on my truck and could tell the differnece before I got my Predator working. I beleive it was worth the $100. http://www.airaid.com/dyno.asp
 

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Discussion Starter #12 (Edited)
QUOTE=HD-Fatboy]Jim, I take it that your's is an 04. How much differnece between the LS1 5.3 and LS2 6.0? The 05 0-60 times are around 5.29-5.49. If the difference is cams, heads and throttle body I would think it an easy upgrade. I believe the throttle body inlet on the 04's are 85mm and the 05 has a 90mm. That would probably add to the breathing for the engine.

You make a good point here. How many of the 05 parts would in fact be compatible with our LM4 5.3 liter engines I wonder? And, how much labor and retuning cost would be involved?

Also what factor do our tires play in the game of performance? I can understand our fatties on the back for traction but not the front. I would think it requires more hp to turn them than a set of 60s or 70s up front.

The biggest negative of wide front - and rear - tires is the moment of inertia penalty you incur. Those wheel assemblies are heavy, and the moment of inertia actually increases with the SQUARE of the radius. This is a very tangible penalty. On motorcycles, replacing the stock aluminum wheels with carbon fiber wheels lowers the 1/4 mile ET by 0.1 to 0.2 seconds, depending on the relative power to weight ratio of the specific bike/rider combination (I model this many times a month for my Gearing Guru Performance Modeling clients). But, those big and wide tires on the SSR are an integral and essential part of the vehicle personality!

Also what about brake rotor size? I saw on I think NOPI TunerVision were they added larger rotors to a car and it decreased the time on the car. So would smaller rotors add any increase in speed?

Brake rotors have the same moment of inertia potential impacts as the wheels, but smaller. But again, good brakes are especially important on a 4639 lb vehicle, and braking effectiveness is very adversely affected by reductions in rotot diameter.

You may want to look into the Throttle Body spacers. Airaid has dyno charts on their site for a 5.3 Tahoe. I have one on my truck and could tell the differnece before I got my Predator working. I beleive it was worth the $100.

You have to be very careful here. The impact of these spacers changes a LOT as you change other factors in the intake or exhaust system and affect the airflow. The effects will be positive in some areas and negative in others, and could "fight" other mods in certain rpm ranges. That would have to be custom tested on a dyno, after the other mods are installed, and would be costly far beyond the $100 cost of the part as you are tying up both a technician and a dyno.

The monent of intertia thing got me thinking about lightweight flywheels. I have modeled, and actually installed on one of my own bikes, really lightweight flywheels (9 ounce aluminum versus 4.1 lb steel!!). They have a HUGE effect on performance, much greater than the lightweight wheels do, because they spin at the highest rpm in the entire drivetrain system: engine rpm. And, lightweight flywheels are an accepted accleration improving device for that reason on cars as well as motorcycles. On motorcycles, they also noticebaly quicken the handling, as the flywheel spinning at 4000 to 10,000 rpm is a significant gyroscope.

I read a report a while back where the author replaced the stock flyhweel on an import car with a lightweight one, and found through calculation and subsequent road test proof that the heavy stock flywheel was diverting close to 40 horsepower or so to spin it up (high moment of inertia), where the replacement took only a tiny fraction of that power to spin up.

I wonder if there are lightweight flywheels available for our 5.3L LM4s, and how much cost, parts and labor, is involved.

Jim G

http://www.airaid.com/dyno.asp[/QUOTE]
 

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Discussion Starter #13
I just realized the obvious, looking at the rpm versus time graph and the speed versus time graph.

I should shorten the WOT shifting time.

Those of you with a Predator, a Superchips, or a Crane, how much did you shorten the WOT (not part-throttle, just WOT) shift times?

I know that these units do that even in their default performance mode, but also let you customize it further.

How much did you change it?

Jim G
 

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So far I havn't changed my shifting from that of the 87 tune in the Preadator. Second gear comes on strong and fast, almost like you were kicked in the back in WOT. Third doesn't seem as strong as second. I'll hook up the Predator and try and get the numbers for you.

Another thing I used to have on my 69 Camero was a cooling can. Gas line came into a can, spiraled around and back out. You filled the can with ice to cool the gas down. MOROSO was the brand. http://www.prostreetonline.com/buy/moroso_fuel_cool_can/mor-65125/

Another Item I can think of is Underdrive pulleys.

What about Nitrous?

Drycell battery

I have seen in some of the parts mags flywheels that weigh under a pound for a 5.3

http://www.ls1tech.com has a lot of good info on the LS1. I drop in there once a week or so.
 

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So far I havn't changed my shifting from that of the 87 tune in the Preadator. I'll hook up the Predator and try and get the numbers for you.

I believe that all of the Predator's tunes incorporate fatser shifting by default. So, even though you did not manually adjust it, the Predator programming itself did. If you pretend to want to change it, and then cancel out, it will show you the current setting. I would appreciate it if you could pass that setting on to me!

Another thing I used to have on my 69 Camero was a cooling can. Gas line came into a can, spiraled around and back out. You filled the can with ice to cool the gas down. MOROSO was the brand. http://www.prostreetonline.com/buy/moroso_fuel_cool_can/mor-65125/

I don't want to add anything that requires regular "maintenance or resupply"!

Another Item I can think of is Underdrive pulleys.

This makes a lot of sense for me in particular, because, remember, I have installed 4.56 gearing, so my engine is spinning 22% faster much of the time. So, I could probably slow the accessories down to near where they were (22% slower) and have no problems, except at extended idling or stop and go.

What about Nitrous?

I don't want to add anything that requires regular "maintenance or resupply"!

Drycell battery

Modern car electronics are very sensitive to battery voltage and draw capacity. Not sure I'd want to take the chance, especially since the weight saving would be relatively small on a 4700 lb vehicle.

I have seen in some of the parts mags flywheels that weigh under a pound for a 5.3

Is the flywheel still a separate item on an automatic-equipped engine, or is part of the torque converter housing? I have no idea about car flywheels (have only done motorcycle ones!). If it is still a separate item, and if readily accessible without tons of labor, this would have high potential! Anyone know?

http://www.ls1tech.com has a lot of good info on the LS1. I drop in there once a week or so.[/QUOTE]

Thanks for the ideas! I will investigate the ones listed above.

Jim G
 

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Flywheel

Based on old knowledge (used to take my own cars apart all the time when I was a kid) GM flywheels for their automatics were nothing more than a very lightweight "flexplate" that was used to hold the teeth for the starter motor to engage with and it was bolted to the crankshaft and the torque converter. I know that sounds like the description of a traditional flywheel, but it is really nothing more than a piece of metal to connect the crank and torque converter.
 

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Discussion Starter #18
Bass656 and Mofo: Thanks! That's the temrinology I needed to do a search to see what is available!

Jim G
 

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Dynatech Suprmaxx headers?

What are the odds?

I called the the local shop that did my 4.56 gears to ask them how much they would likely charge me to install headers if I found a set I liked.

Turns out that their shop was one of the first places to get a set of Dynatech Supermaxx headers when Dynatech first developed them. Lamar and Rob put them onto an SSR that I have mentioned in other posts, that is driven here in Atlanta, and that sports a supercharger that Lamar and Rob installed and tuned!

They told me today that they really liked those headers. They "woke up" the supercharged SSR and were not hard to install.

However, because the "before" and "after" dyno runs were done with the supercharger already in place beforehand, the dyno data is useless in projecting what effect those headers would have on MY stock SSR.

Rob is going to give me a price next week for those headers including installation, if I can convince myself in the meantime that they are actually worth the money in terms of performance improvement achieved on an otherwise stock SSR.

Jim G
 
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