Why is the LS1 so much better than a 351W?

Discussion in 'Fox 5.0 Mustang Tech' started by 9 Deuce GT, Nov 27, 2005.

  1. Thats crappy crapola

    Thats what I like best about my mustang compared to my focus, you dont have to rev it at ALL to get it going. Right from idle it will take off with no complaints. This is with a H/C/I 306 w/ 3.55 gears btw :nice:

    My car also can start from second, and when the revs get to 2000(not sure on speed, my speedo is broke!), I can shift to 4th, then when 2000rpms come again, I shift to 5th, no problemo
     
  2. Actually I was wrong. I'm intalling a 6 disk CD changer in my car, so I moved it around in the barn. At idle, it needed no gas to move. So Stang2841 was right.
     
  3. damn he really must of sucked at driving or was a ****ty combo. How bad did u beat him?

    he must not have the WS6. Them cars car like a dream compared to fox mustangs!!!
     
  4. I have nothing against TFS heads, but I would like to stay with AFR. They have treated me good so far. But, I may have to switch due to this emissions issue. Chances are the laws won't effect my year vehicle, but I really hate to take a chance only to lose big with the heads. The intake, cam, exhaust, etc., etc., I don't mind changing. It's just the facts that the heads are so expensive initially.

    As far as $$$$$, obviously I don't want to spend a fortune. The ported TFS heads aren't that much more than the AFR 205's. So they may be an option. The cam, and intake I will not skimp on this time. Porting of the intake is a must. The cam will deff. be custom. So where does that leave me? Who knows. I will just have to build this thing as the time comes.
     
  5. Keep in mind as well that Chevy has a lot of high tech electronics on those engines. Knock sensors allow them to really walk the ragged edge on timing, which really helps too.
     
  6. Why DOESN'T a 40-year-old-design engine outperform a 10-year-old design? What would have happened if someone had said, "By God, Henry got it right the first time. You can make just as much power with a flathead as a small-block....Why not just mod that flathead?...blah, blah, blah..."? I can't tell you why an LS series makes more power. That's like a PE teacher talking mechanical engineering...wait; that's ME.

    In all seriousness, computer modeling makes it easy to see what works and what doesn't without even casting a part. That's what a multi-million (billion?) dollar R&D department will do. C'mon, lets not fool ourselves here. GM no more used the old 1st gen. design for its LS series than Ford used a flathead design for it's modular engine. There is NO comparison for an LS series engine to a Windsor engine...nada, zip, zilch!
     
  7. Another reason why the LS makes HP easier out of the box is because it has like 11:1 compression. Any mod really takes advantage of it. I am not sure if ford ever released a facory 351W with 11:1. It does have its limitations because my friend's supercharged GTO gets can only run 5-6 lbs of boost or his engine bay will potentially turn into ground zero. Especially the way he drives it...
    Kevin
     
  8. 4V 351C vs. LS1

    Stock heads on both with an intake and solid roller cam for the cleveland and the LS1 gets the same (ext for the solid roller,it sticks with the hyd. roller).Both motors would have 7000rpm plus capabilities (at least,I think they would :) I know the Cleveland could do it).

    And I dont think its fair comparing a stock 351W with a stock LS1 if any were to start with that.Simply because there newer and already have parts like aluminum heads and good intakes from the factory.

    edit:and Im not talking about a 30 year old,1000000 mile plus Cleveland either.More like machine shop rebuilt with 11:1 compression mathing the LS1,and a decent valve job.
     
  9. I was on the highway going to work and had the cruise set at 75MPH. I passed him, then he stayed at my door, and motioned if I wanted to run. He said he wanted to go from a 50MPH roll, so we did. By 125MPH I had 2-2 1/2 car lenghts on him and still pulling.
    We both got off on the same exit and started to talk, and that's when he said he had h/c/i/e. I know for sure it had a cam and exhaust.

    From a dig, it probably would have been a different story I believe. He probably would have jumped quite a bit, but then would start to get reeled in.
     
  10. What does the "e" stand for in h/c/i/e?
     
  11. the ls1 is built better from the factory therefore can pass emissions. The 351 mostly sucks from the factory and you have to do a lot to get the same power as the ls1. But you can go with afr 185s, and other supporting parts and should run with those ls1s. I have a buddy with a 99 z28, all bolt ons,hot cam, stock unported heads,and fast intake, with 4.30 gears and slicks, auto trans, running 10.80s in the 1/4. that is fast.
     
  12. I think AFR has a "stage 2" like porting that you can get. Might be worth looking into.

    Also when looking at cfm flow with AFR make sure to check the bore diameter of the test. 205 are tested like they are on a 4.125" bore and the 185's are on a 4.060" bore. Don't get me wrong I like their stuff.
     
  13. No one's arguing the fact that you can easly make the ls1's veeeeeeeery fast and yes the ls1 is newer, takes to mod's well and is more "modern", but that doesn't mean the 351 "sucks". for the most part the 351 has never been a performance engine. Yes they were used in early Mach's and some GT 350's, but were rated @ 290 hp. If I remember right they never came with a 4 bolt main (Cleveland did) were notorious for restrictive heads (aftermarket has fixed that) and except for the Lightning never really were used to their potential. To be able to take a mild mannered engine and make it run with an engine design for performance proves its worth.:)
     
  14. its ALL IN THE HEADS!
     
  15. I really have to disagree with you. I don't know why it is but all Mustang and LT1 guys seem to think the LS1 has no bottom end grunt.

    WRONG

    They actually make nearly all there torque at 2500rpm, they then have an almost completly FLAT torque curve to the PEAK @ 4400rpm where it slowly drops off.

    The make more low end torque than an LT1 STOCK for STOCK.

    In many ways this is half the reason they make such good high end power.

    There are TWO main reasons for this. Both related.

    Firstly, how HP is derived. To get an HP reading we use a BRAKE device (hence the B in BHP), this is either an engine or chaissis dyno like a Dynojet or Mustang Dyno.

    HP = torque (lb ft) x rpm / 5252

    So to get a higher HP number you must either:
    -produce more torque at the same rpm
    -produce the same torque at a higher rpm
    -or produce more torque at a higher rpm

    The LS1 manages to produce a lot of torque very high in the rev range (~350lb ft @ 4400rpm). The 351 may make similar torque but it will be lower in the rev range, and thusly the BHP figure will be lower.

    So this is WHY LS1's produce more power.

    The HOW they produce it is far more complex.

    In simple terms it is a better engine (I know this is a Mustang forum, but the truth is the truth).

    The key to power is efficency. The LS1 has as already mentioned very good flow rates. But more than that it gets more in percentage terms from every combustion cycle.

    Light weight and low friction components play a big part, as does the combustion chamber (piston, valve position size, spring rate, size and shap, spark plug location and so on). Even the material used. Not too mention that modern engines are designed with CAD (Computer Aided Design) and built using CAM (Computer Aided Manufacturing). This all adds up to better built, lower tolorancies and fewer descrepancies. Back in the 60's when the 351w was being used such accurate manufacturing methods where decades off.

    The oil and cooling system (internal engine pathways) also will help. As does modern electronic ECU's and fuel injection.

    In every area the LS1 will basically out perform the 351w. But the 351 is not alone as the LS1 also out performs ANY (Ford, Dodge, GM, etc.) engines from the past that are built along the same lines.

    And it doesn't stop there either. The new Dodge Hemi out flows nd out performs the LS6 in almost every area internally. And at least has the potential to outperform it in the BHP department too. And chances are newer engines yet to be released will out perform that as well.

    Efficency is the KEY and always has been. That is why OHC/DOHC engines can produce a much higher specific output than a push rod OHV engine. The only limiting factor is they are usually of a much smaller capacity, so their total PEAK HP numbers are not any higher if at all. But if they produced large capcaity DOHC engines then they WOULD outperform the OHV push rod engines. An irony really.

    Think about it, even the best LS1's struggle past 450rwhp and remain streetable as a n/a motor (yes of course more is possible, but at a sacrifice). So that's only about 500bhp at the engine.

    It's specific output is only 500 / 5.7 = 87.7bhp per litre. Which is pretty darn good for an OHV. Many older OHV engines will struggle to make it past 75bhp/litre and still be streetable (even when forgetting about emmissions).

    Yet an DOHC design will often support 100bhp/litre or more.

    Image if Honda (yes I know, I know, but bear with me) made a 4.0 litre V8 out of their 2.0 4 cylinder engine.

    It would be a 32v DOHC lightweight aluminium engine. With the potential of 120bhp/litre specific output.

    So from only a small capacity it could produce 480bhp STOCK and emissions LEGAL.

    However, there is no need for such engines so it is rare to see any actually produced.

    The best I know of is the TVR Speed 12 engine. It's an all aluminium DOHC V12 7.7 litre with 880bhp STOCK LEGAL EMISSIONS on what would be 91-93 octane fuel.

    It makes the new LS7 7.0 Litre C6 Z06 engine with only 512bhp look like it's 'slightly' under performaing doesn't it.


    Dynamically newer technology will always win through. In the case of the 351w vs the LS1. The LS1 is the better designed engine, hence it produces the most power. But the LS1 is by no means the pinnacle of engine design however. It just happens to be VERY good and very available, especially in the USA.

    Hope this helps.
     
  16. Total Rubbish!!!!!!! :nonono:

    STOCK LS1 CR is 10.1:1

    Also they handle boost just fine. MOST of the kits (Fbody/Corvette) are designed to run 7-8psi on a STOCK engine. This is perfectly fine.

    With a very good tune and a little bit of luck 12-14psi has been seen for some people.

    The biggest limit is BHP as 550bhp+ (engine) and it will start breaking parts. For most people to reach this power (sustained so not NOS) they will need FI. However it is unlikely to be the boost itself that causes a failure. Unless the tune (a/f) is off and detonation occurs. But this can destroy an n/a engine as easy as a boosted one.
     
  17. and intake.
     
  18. My mistake 10:1. He is putting 425 torque and HP at the wheels. He was getting detonation and had to install Methanol injection to alleviate the issue. He has had it tuned on several occasions and has the supporting fuel mods to compensate. May not be true for all LS1 engines but for his engine 6 lbs is going to be the limit. Still... 425 at 5-6 lbs isn't anything to scoff at.
    Kevin
     
  19. true.

    Do you know what sort of blower it is? Maggie, Procharger, KB??

    And is it intercooled?

    If they're still having problems they should speak to Bob @ Exotic Performance Plus. He'll get it sorted.

    An Fbody with catback and LT's with an IC Procharger D1 should be able to run 7-8psi with 440rwhp (Mustang dyno) safley on 91-3 Octane fuel.