GT350 vs. Z/28

[americansteel]

I can't find pics of dynos I've seen in person because I took those on my iPhone 4S before it was stolen and I got my 5s. Anyways, they looked very similar to these examples. I've seen a modded cammed zl1 make power to almost 7,000 even with higher boost so the lsa can definitely be built to handle 7,000 but Chevy I don't believe intended the factory valvetrain to spin that high. The gt500 does so pretty easily and nicely stock and modded.

Stock zl1 before and after tune (auto)




Stock 5.8 gt500 before after just a diablo tune

any pushrod engine can be made to rev to 7K with out issues depending upon valve train weight that also effects how the valves react. but an LS engine can rev to 7k. GM isn't going to make pushrod engines to rev to 7K because of like you said before valve train issues and float. warranty claims out the ass I can see. OHC engines don't have that problem like pushrod engines do although many people don't know this but OHC valves can float. as I stated before I have never seen a stock GT500 make power past 6500 I seen them rev to 7k but not make power at that RPM or even the higher 6's.

 

[jacker1991]

Great time to be a Ford/Chevy enthusiast. The performance of 2011+ cars are out of control...Love it!

 

[americansteel]

Great time to be a Ford/Chevy enthusiast. The performance of 2011+ cars are out of control...Love it!

unfortunately ford doesn't offer car options for the "enthusiast" in the performance world, it would be nice to have lets say a fairlane or something along those lines.

 

[tt335ci03cobra]

He suggested bolt ons skew the results but according to the graph I posted it means very little in power curve, just more power. The same dynamics are all still there because the internals were never touched. The bolt ons just allow the engine to perform at it's peak vs restricted. I would think as a seasoned engine builder he would realize that.

Yup, I've seen all types of stock and mild mod gt500's (trinity) and none have been 62-6500 peakers.

On 03 cobras, pullied for 14-15psi, they peaked at or below 6,000 rpms almost always.

Reason I pointed out that the 2013 doesn't even drop peak rpm point that much when upgraded with extra boost was to show the contrast to the typical norm that extra boost almost always drops the peak rpm hp point.

But I did upload a 100% stock (with a tertiary diablosport tune result) pic to show how they also perform bone stock.

 

[tt335ci03cobra]

any pushrod engine can be made to rev to 7K with out issues depending upon valve train weight that also effects how the valves react. but an LS engine can rev to 7k. GM isn't going to make pushrod engines to rev to 7K because of like you said before valve train issues and float. warranty claims out the ass I can see. OHC engines don't have that problem like pushrod engines do although many people don't know this but OHC valves can float. as I stated before I have never seen a stock GT500 make power past 6500 I seen them rev to 7k but not make power at that RPM or even the higher 6's.

Ok, fair and true. I did just upload 2 dyno graphs of trinity gt500 hitting what I claimed as power at and above 6700. Are you saying you've never seen that in person? I'm asking because I just listed 3 pics showing so.


The very first was a stock zl1 doing it's drop by 6200

First gt500 was stock, and then with diablo tune which both did power into 7000

Second was modded with extra boost and still power climbing till like 7000

 

[svtfocus2cobra]

Nice! Didn't even think of using that calculator lol.

 

[americansteel]

He suggested bolt ons skew the results but according to the graph I posted it means very little in power curve, just more power. The same dynamics are all still there because the internals were never touched. The bolt ons just allow the engine to perform at it's peak vs restricted. I would think as a seasoned engine builder he would realize that.

I don't know much about electronics tuners. I don't install turbo's or superchargers in cars I build engines that get boosted or just have work done to them for a tuner here in Delaware. I do know there are tunes that can raise the RPM band but not by much, in order to raise the RPM band camshaft duration has to be changed because adding boost its self wont raise rpm. I stated before I have never seen a bone stock GT500 make power past 6500 but can rev to 7K, I have never seen a GT500 make power at 6800 or higher with out any kind of bolt on's. adding pulley's tunes exhaust all react differently on a boosted engine but still they all make more power. as a seasoned engine builder I do know that!
the internals wont effect power output by much even if compression was raised or lowered slightly the internal parts that would effect power is the camshafts. what would drastically help the GT500 is if the lower manifold was ported a bit, if the heads were ported there isn't much power to be had. I seen many GT500's on the dyno with and with out bolt on's.

 

[americansteel]

Ok, fair and true. I did just upload 2 dyno graphs of trinity gt500 hitting what I claimed as power at and above 6700. Are you saying you've never seen that in person? I'm asking because I just listed 3 pics showing so.


The very first was a stock zl1 doing it's drop by 6200

First gt500 was stock, and then with diablo tune which both did power into 7000

Second was modded with extra boost and still power climbing till like 7000

the GT500 can redline at 7K, by adding bolt-ons the power will increase up to where that engine can red line at. I've seen them with bolt ons make additional power at 6500RPM and I seen them make power up to 6900-7K its all about what has been done. I seen them with just tunes make power at 6500RPM and I seen them with tunes make additional power to 7K.

 

[darreng505]

the GT500 can redline at 7K, by adding bolt-ons the power will increase up to where that engine can red line at. I've seen them with bolt ons make additional power at 6500RPM and I seen them make power up to 6900-7K its all about what has been done. I seen them with just tunes make power at 6500RPM and I seen them with tunes make additional power to 7K.

Your eyes deceive you man. Its better to know the truth than just claiming to see some dyno of some car by some tuner at some place.

Facts are facts and they are posted.

 

[tt335ci03cobra]

Ya to clarify, the first gt500 pic I put up has BONE STOCK RIGHT OUTTA MICHIGAN 2013 TRINITY GT500 vs ONLY DIABLO TUNED.

It was a post on ls1 tech by diablo themselves to show how the stock gt500 dynos and how it responded to only their tune.

The graph clearly shows two dyno pulls, one is BONE STOCK and makes power to 7,000. The second is 40whp stronger, makes power to 7,000rpms and is the diablo tuned otherwise stock car


I posted the other photo because I didn't think anyone would need multiple examples, and figured one bone stock, one tune only, and one bolt on with tune would be enough.

Also, an ecu programmer can mildly shift power around by manipulating timing and air fuel but manipulating what the cams and valvetrain actually want to be doing (running it lean, high timing etc) is not very safe and almost no tuner worth their dyno hardware would tune a car in that kinda way.

You can pick up or level power nicely but in general, most tuners don't look to pick up tons of power right at redline because of the liability if it blows up.

You could switch the fuel map lean and throw 25-30* of timing at 6500+ rpm to really pick up power up there but it'd be a time bomb and blow up the first time it gets bad/old gas or the driver wots into the rev limiter.

Safely, taking away a small amount of fuel and keeping timing stable up high in the rev range is good for at most a 1-3% boost in power up there from what I've seen on factory cars. That's 2-6whp on a 200hp motor, and 6-18whp on a 600whp combo like the trinity gt500. Diablo picked up 40whp, which is still probably really safe because it's only a 6.5% pick up, and Diablo has been doing tuning for over a decade so they know what they're doing.

 

[americansteel]

Your eyes deceive you man. Its better to know the truth than just claiming to see some dyno of some car by some tuner at some place.

Facts are facts and they are posted.

LMFAO I see you're hawking this thread! facts are facts when I see a car lay down said power in front of my eyes, do you not know all dynamometer's are different? you can have one car on one dyno and that same car on the other dyno make different power. my eyes don't deceive me you just choose not to believe me because facts that I have written on here that I have seen personally differs from your opinion. if I see a GT500 make peak power at 6500 RPM but can redline to 7K, that looks like the truth to me! am I missing something here???

 

[tt335ci03cobra]

I can search google, and ask my mechanic for some examples as well. If I drop everything I was planning to do for the next 2-3 hours, I could probably find 15+ examples.

I believe the easy button would be to link to the 2013 gt500 stock dyno thread though so I will probably do that now that the idea just hit me. One moment please.

 

[americansteel]

Dyno Chart 2013 GT500 5.8l the power is at 6500 dips to 6600 raises 6700 drops down but redlined at 7K. I cant upload a picture on this site I don't know why im going to ask one of the moderators about that. I have 4 dyno graphs sitting 2 feet from me right now that I would love to post on here and show you. dependin upon what kind of bolts on from what I know power can be made all the way to redline at 7K and some bolts will make power at lower RPM and drop faster than other bolt-ons or over stock. factory power dropped at 6700.

 

[americansteel]

heres another graph of course this was from a magazine. peaked at 6300RPM bone stock GT500. I sent a message to a moderator and im waiting on a reply.

 

[tt335ci03cobra]

So in those examples, they "peak" earlier than 6700, but make with 5-whp of that same power till way later...

Those look like 2 less then normal occurrences and even still, power is basically flat till 6700+.

The 1st pic is a power graph of a trinity gt500 like I've never seen, I'd check plugs and such on that car.

Even still,

I don't see what I'm missing or off about. Sure, because of low smoothing, those 2 graphs show slightly early "peaks" but making 605whp at 63-6500 because of low smoothing and 590-595+whp till redline 700rpms later isn't anything I'd call a drop off. That's a minor spike and dip in the graph because of smoothing. Look at the rest of the second dyno graphs pull, it does zigzagging, albeit a lesser extent, the whole way through the pull.


To me, +/- 10whp is flat line power. My turbo 5.4 made "flat line power" (+/- 10whp from about 5,000-6500rpms. It probably honestly peaked maybe like 5700 or so and dropped 15-20whp from there till 6500, but that to me is flat line power. It was like 880whp at 5,000 to 885whp at 5700 or so and then slightly tapered to 865-870 by 6500.

 

[tt335ci03cobra]

To upload pics, you need to start an imageshack profile, it just asks for an email and password, 2 minutes, and then select upload pic, and it will load the pic, then select the text scroll that reads forum: "urlxxxxxxxurl" copy that URL and paste it in your post.

 

[tt335ci03cobra]

Heres a pump gas tune making 817whp on 15psi with a minor dip in the graph at 6400(?) rpms to show what I mean by dips and spikes.




Here's a 20psi tuning spree with what I call flat line power, I could ride this curve into 7,000 at the big end of the track and not really be down all that much power vs the peak, it tapers ever slightly but doesn't just die and fall off a cliff






Here's what I would call a drop off, it's useless to rev to 7500 in this application




Here's a car that "peaks" at like 7200, but it's definitely worth staying in it till 8,000



I guess we are arguing semantics, in 100% definitional terms, ya a hand full of trinity's may "peak" earlier than 6700+, in bone stock trim, but it obviously worth staying in gear and not up shifting early to counter a falling power band. That it stays within 5-10whp of peak well past the "peak" (spikes imho) those two dyno graphs you loaded, is fine by me as proof that the trinity doesn't tap out at 62-6500rpms.

My point originally was the lsa taps out early and starts dropping pretty bad after 6000-6100. I laid the facts that gm engineered it to do so for safety because pushrod engine, boost, heavy car, and warranty. I stand by that. Ford let's a 4.165 stroke motor rev to 7,000 with almost twice the boost as an lsa, and with tiny bore spacing because dohc advanced tech liners.

This was all examples to prove that ohv's tend to be engineered by their manufactures to deliver power between 1500-6000rpms because the ohv is inherently limited to valvetrain stability at higher rpms, and to warrenty the mill, oem ohv's are bigger, like 5.3-7.0 liters, and usually in factory trim are torquey down low since they are optimized to that 1500-6000powerband. Ultimately, although a dohc could be built to outperform an ohv from1500-6000, it's more advantage to gear a similar displacement or honestly, for mpg, smaller displacement dohc vehicle for a 2-7,000 rpm band because power is easier to make at 7,000 rpms, than at 6,000 if the airflow and stability exist to do so (because hp is a relation of rpm * tq value @5252rpms all divided by 5252 rpms in ideal airflow conditions).

My whole point was factory vs factory, an ohv has an easier time making low end torque because they are engineered to do the best with their limits which are high rpm stability.


I think my point is proven, and I honestly have spent way touch time on this discussion today. If you think I'm still wrong, uninformed or whatever, you win, and are right. It's been fun, upload some pics of that sick sounding 2 door 6.2 when you can.

 

[americansteel]

I guess we are arguing semantics, in 100% definitional terms, ya a hand full of trinity's may "peak" earlier than 6700+, in bone stock trim, but it obviously worth staying in gear and not up shifting early to counter a falling power band. That it stays within 5-10whp of peak well past the "peak" (spikes imho) those two dyno graphs you loaded, is fine by me as proof that the trinity doesn't tap out at 62-6500rpms.

My point originally was the lsa taps out early and starts dropping pretty bad after 6000-6100. I laid the facts that gm engineered it to do so for safety because pushrod engine, boost, heavy car, and warranty. I stand by that. Ford let's a 4.165 stroke motor rev to 7,000 with almost twice the boost as an lsa, and with tiny bore spacing because dohc advanced tech liners.

This was all examples to prove that ohv's tend to be engineered by their manufactures to deliver power between 1500-6000rpms because the ohv is inherently limited to valvetrain stability at higher rpms, and to warrenty the mill, oem ohv's are bigger, like 5.3-7.0 liters, and usually in factory trim are torquey down low since they are optimized to that 1500-6000powerband. Ultimately, although a dohc could be built to outperform an ohv from1500-6000, it's more advantage to gear a similar displacement or honestly, for mpg, smaller displacement dohc vehicle for a 2-7,000 rpm band because power is easier to make at 7,000 rpms, than at 6,000 if the airflow and stability exist to do so (because hp is a relation of rpm * tq value @5252rpms all divided by 5252 rpms in ideal airflow conditions).

My whole point was factory vs factory, an ohv has an easier time making low end torque because they are engineered to do the best with their limits which are high rpm stability.


I think my point is proven, and I honestly have spent way touch time on this discussion today. If you think I'm still wrong, uninformed or whatever, you win, and are right. It's been fun, upload some pics of that sick sounding 2 door 6.2 when you can.[/QUOTE]

this has been bothering me. as a person that has been building engines for almost 10 years now i can safely say that your comment is wrong. but only to a certain point is it right. ohv do not has an advantage nor were they engineered or designed to make peak torque faster or more of it at a lower RPM compared to an ohc engine. but torque production has a lot to do with stroke camshaft duration and intake runner length. its called air speed manipulation the more stroke the more air is being pulled in short duration and long narrow runners creates more torque, ohc or ohv designs all open a valve that cylinder is drawing in air you can manipulate where torque is made if there is 2 valves per cylinder there is more air coming in doesn't mean it raises rpm it just mean there is more air and fuel to be combusted spinning a crank thus creating torque rotational force. valve design doesn't matter when creating torque. you can have 330 cubic inches with a 4 inch bore and 3.270 stroke or 4.165 stroke and 3.556 bore the longer stroke will create more torque but not power. add that 4 inch bore to the 4.165 you have more air and fuel pushing down on the side's of the piston creating more downward force = torque. how ever that stupid long stroke isn't ideal for high performance. unfortunately that's what ford wants to use. 3.900 x 3.800 would have been perfect for both truck and performance. low end torque production has nothing to do with whether an engine is OHC or OHV designed. its all about stroke/bore cam duration and intake runner length. we all know the modular engines and coyote engine cant make the torque like an LS engine make but of course the LS engines have displacement. the nature of smaller engines is to rev simple as that. fact! the 5.8l in N/A trim wouldn't rev to 6600RPM to make the power of the 5.0 instead it would be about 6100RPM. but the 5.8l has the abilty to rev to 6600RPm or even to 7K with out an issue unlike an OHV engine. torque production has nothing to do with valve train design. i wrote a day ago that i tested a stock 6.2l ford engine and the dyno results of a rebuilt 6.2l LS truck engine that ford 6.2l made more low end torque at a earlier RPM than that LS 6.2l did and made more power. smaller engines have to rev so comparing a modular or coyote engine to an LS engine is stupid in terms of power and torque production. you are right about GM not wanting make a high revving OHV engine, warranty issues would pursue if that were the matter. how ever there is no need it! its the nature of OHV engines any way regardless of size. your duration is the limiting factor in engine speed doesn't matter what kind of valve design.

 

[tt335ci03cobra]

Same displacement vs same displacement and both having same intake sizing, ohc will make more power everywhere vs ohv.

That's said, ohc's are engineered different than ohvs and each is factory tailored to it's strengths factory.

That's awesome that you've been building engines for 10 years and I don't mean to take anything away from that, my point is simply that when comparing factory oem engines, like the ls vs modular engines, they are tailor built to their strengths. They are also geared accordingly to compliment their strengths.

Take a modular 5.3 bb (which is not a factory engine and really muddles everything now but anyways) vs an gm ohv 5.3 and compare their power curves. They are different power curves even when both are built to produce the same modest power and keep the same displacement.

Compare a gm 4.7 vs a modular 4.6, both make different power curves even at just 280hp.

Now when building engines, you can really tailor the powerband just as I'm sure you've seen, and as you know, ohv isn't as dynamically efficient as ohc

 

[germeezy1]

I am not sure why making say 500 rwhp at 6,300 rpm, and having more power under the curve with no other drawbacks is a bad thing.