lobuxracer

iTrader: (2)

There's something very wrong with both of those dynos. ALL dynos cross torque and hp at 5252 rpm. It's a mathematical thing. Since neither of these does, there's something they're not telling you. Scaling is certainly part of it, but there's something else they're doing (or not) to explain why they look so odd.

11.5:1 compression and 16 psi of boost? Not on any pump gas less than 100 octane. I really don't believe everything I read on the Internet because I've built and blown up enough engines to know where the limits are. You can do some basic work with the universal gas law and figure out exactly how much temperature rise there is at 30 psia compressed 11.5:1. It will easily autoignite well before the sparkplug has a chance to fire.

If you're shooting meth or water or a combination of the two, you can get away with a lot, but you can't escape the basic physics.

TrueStreet

What do you mean all dyno charts cross tq and hp at 5252rpm? Doesn't it depend on the scales? The charts can be different looking depending on the chart itself. Most GM dyno charts show around 2~3K, some BMW ones i've seen high 4K. Definitly nevery spot on 5252rpms. I know what you're talking about when the two power bands cross at 5252rpms, but that doesn't mean it will on a chart because of how it's graphed is usually different from dyno chart to dyno chart.

Here is one of their graphs with lower boost.



6psi and over 80hp gained. That should look possible.

Kurtz

iTrader: (1)

Horsepower can't be measured.

It's calculated from torque.

.............................TQ*RPM
The formula is HP=-----------
.............................5252

Therefore HP=TQ exactly at 5252 rpms. 100% of the time.

Any dyno graph that doesn't look like that is either fake, done on a malfunctioning dyno, or has some sort of shift/correction applied to it and results can't be read as literal unless you are told WHAT that change/correction is.


In the case of the dynos you're posting the problem seems to be that it's showing the HP and TQ curves on the same graph, but using different scales for each, hence the lines don't cross where they should.

TrueStreet

exactly, I'm not disputing the 5252rpm thing, I was commenting that you're initial disapproval of the chart because the bands don't cross at 5252rpms isn't rational as many charts aren't shown in the ideal situation. Especially the SAE dyno charts that GM posts, I don't think I've ever seen one cross at 5252 that GM has posted.

Point being is that I'm sure the F head can flow well enough to take low boost on a 2GR or 4GR if tuned properly. I don't think the 2ZZGE is an exception, it has 11.5 CR, yes the G head has a wonderful design, by Yamaha, but I think the toyota F head isn't too bad for low boost. And with a great tune I'm sure people could boost their 2GR/4GR with no problems.

lobuxracer

iTrader: (2)

OK, but port design has nothing to do with detonation resistance. Available boost without high octane fuel or water/meth injection has everything to do with combustion chamber design. Yamaha does combustion chamber design very well. Toyota, not so good. I really doubt the angled squish in the 2GR is the best design for boost on high compression, and worse still, executing angled squish in a production environment where machining tolerances always allow for too much means every single engine will roll off the assembly line different. The differences I've seen in individual units can be amazing.

TrueStreet

ok i understand. Has anyone tried though?

Kurtz

iTrader: (1)

Two different companies (LMS and TOMs) have built supercharger kits for the IS350. Neither was safely able to produce a kit running even 6 lbs of boost due to the high compression.

The LMS kit is 5 lbs...the TOMs kit, running 100 octane with the ECU reprogrammed for 100 octane, runs 5.8 lbs.

Making it a turbo rather than an SC doesn't magically let you run a ton more boost on the same engine.

TrueStreet

oh yea totally agree turbo doesn't mean you'll have any difference than a S/C in terms of boosting. just turbos kits can be fabricated easier than a s/c kit. I wonder what compression the S/C 2GR-FE is running at that TRD did. Wasn't that impressive, bumped power over stock (268) to like 320hp, but did get a nice bump in tq to 300. The only factory DI boosted engine I know of is the LNF motor from GM, the 2.0L one found in different SS models and the turbo Sky/Solstice. Those have fairly low compression around 9.2:1. But man that TQ on that engine is AWESOME! If someone would turbo a 2GR-FSE with proper internals I'd love to see its TQ band if it can achieve anything like the LNF can. I mean the TQ on the LNF hits peak at 2500rpms and keeps it all the way to 5200RPMs, that's pretty impressive to me.

Kurtz

iTrader: (1)

How do you figure?

A SC kit just needs the intake side of the plumbing and a pulley/belt.

The turbo kit needs at least one custom header and all the exhaust plumbing as well as the intake side.

A turbo kit should be more -efficient- but it should not be easier to fabricate as it requires quite a few more parts to be invented and mounted someplace.