Hellspawn

weight difference on my car, documented by Mas280, the previous owner:

1993 touring 5-speed

Before

LF 729 RF 695
LR 705 RR 692

Total--2821lbs

After swap 1999 ls1/t56 trans ac and power steering

LF 748 RF 717
LR 683 RR 700

Total weight 2848lbs


Weight gain only 27lbs


If MYLS18U isn't a metally challenged 12 year old with anger problems, I feel sorry for him. Actually I feel sorry for him either way.

GDJ

Hood scoops are only for looks anyways. Ram air is totally BS on street cars. At least with the WRX and T2, the hoodscoops are actually serving a purpose by sending air through the intercooler, making the engine more efficient. Why do f-bodies have hood scoops? Oh yeah! To make them look bad! Honestly, the f-bodies are some of the worst looking cars ever made. So why wouldn't you take the awesome engine and put it into a quality, good looking car like the RX7? Not to mention you're going to be 500-800 lbs lighter, and won't be labled a redneck.

zkeller

iTrader: (47)

Autronic is an awesome unit. My car ran perfect on it. Tuning is a breeze. To use the Autronic on the LS1, you will need a FAST decoder on the CAS, and you would have to run coils that do not have ignitors built into them. Dual-post wastespark configuration would be optimal. I am not sure on the injectors. I did not look into it, but I am sure it will run them without a problem.

wanklin

iTrader: (2)

I've heard nothing but good things about the SM2 ;o) Thanks for the info, I'll do a writeup on my setup if I decide to use it.

gnx7

iTrader: (10)

MyLS18U= Wile E. Coyote aka "genius"

Invest some money in your education and not all in your car. It will allow the rest of us to understand what you are trying to say.

"IF the ls1 had the same mods exactly as u do in your rx7 it would smoke your ***."

You obviously don't understand a thing called power to weight ratio and the fact that Mazda put teams of engineers on the RX-7 design crew to keep the weight down. A much different league than the engineering level that goes in a $25K Camaro with the design that hasn't changed since '93 aside from the front clip. Plus they are pumped out by the hundreds an hour and when gutted for race car status still weighs a few hundred pounds more than any RX-7/LS1 conversion.

Do your homework big dog or bark on another porch.

jetenginedoctor

No, not even close.

Keep the rotary.

BK

LT1-10AE

A pair of GT25s on an LT1/LS1 should easily put 680HP to the crank at 8PSI. That's not too far away from his 600 to the wheels estimate.

Power your car with whatever you feel like using.

wingsfan

Not close huh? Here's 10psi from a rear mount t70 on an ls1. Just how much do you think he'd lose by running 2 psi less boost?



Please keep your opinions on powertrain preferences to yourself. You're in the other engine conversions folder, not one of the rotary subforums. There's no need to stir up unnecessary drama. If someone wants to strap a solid fuel rocket to their car, let them be.

jetenginedoctor

Is that your car? Bring it by the shop, and we'll run it on my dyno. If it makes that on my dyno, I'll give you $100.

wingsfan

No, not my car, and not my intention to stoke the embers of an online pissing contest either.

What exactly would it prove if it didn't make that number on your dyno? That a mustang dyno reads lower than a dynojet (duh)? Either number is fairly pointless as dyno outputs can be manipulated at will. What matters is the real world performance.

You followed up "not even close" with "keep the rotary". I was just pointing out a car that makes 600+rwhp on relatively low boost. Of course, it's on a dynojet, and he doesn't have a time slip to confirm real world results, so who know what the car actually makes? Closer to 600rwhp than you'd get with a 13brew anyways.

I'm working on a conventional single turbo setup using a T76. I'm hoping to have it up and running by the end of the summer, but I'm still waiting on delviery of some parts.

When my car is running again I'll be more than happy to take you up on your offer and see what it makes with 8 psi. I'll shoot you a PM or an email when I get closer to finishing up.

jetenginedoctor

It's not a Mustang dyno. . . .

Both points very true. However, I know well enough what LS-1s will make in terms of power, and can tell you that 8-10 psi isn't going to make 600rwhp. . . without a 200hp shot of spray.

An LS-1 with a Whipplecharger by Peter Starr Performance (see http://www.starrperformance.com.au/ls1_twin_screw.html) on our engine dyno makes 550hp at the crank with 12psi of boost. Considering drivetrain losses, I feel enormous skepticism when I hear of claims of 600hp at the rear wheels.

Hey, I'm a piston engine guy. You'd think I'd be all for swapping in the V8. However, understanding the physics involved as well as the result of owning a half-this/half-that car with regards to eventual resale value, I just think it's a bad move. Sure, it's your car, your decision. I guess I feel like you're de-evolving the car into a Camaro with an IRS. Anyway, you've got your opinion, I've got mine.

Now that, I'll look forward to seeing! Let me know if you need any help with it. I've got a customer who does nice job fabricating custom turbocharger headers, etc.

Come by the shop sometime for a visit. Be sure and call before you come, to make sure I'm there. See the location information at http://www.appliedracingtechnology.com/index.php

I look forward to seeing you, and good luck with the project!

wingsfan

Well, that's going to depend on the CFM that the power adder adds then isn't it? 10psi from a t76 won't be the same 10psi delivered from say...a T67.

An LS1 hitting 600rwhp with a 200 shot would be making what without it? 450rwhp? 480Rwhp? Seems pretty low for an LS1 with a decent sized turbo on 10psi. The devil is always in the details though.

Hell, a 4000# GTO using a t67 at 11-12 psi hit mid 10s and 129mph trap.

http://www.ls1tech.com/forums/showthread.php?t=317360

That's going to be close to 570rwhp (~670 crank if you ASSume 15% drivetrain loss).



Understood. Of course, the parasitic losses from turning the supercharger account for some of that. Plus, no intercooling...yadda, yadda, yadda.

600rwhp is just an arbitrary number anyways. Nice and round and something to shoot for. Some people just want a piece of paper that says 600 on it and well...dynos don't always tell the whole story.


That's one way to look at it. I actually don't think it hurts the resale all that much. Look around at what a decent FD goes for these days. About $14K-$16K. You'll get more than that for your LS1 converted car. You might have to wait around for the right buyer, but in the end it will sell for more. You'll still lose your shirt relative to what you have in it though.

Any modified car (or car for that matter) is a poor investment. For me, the car is an expensive hobby, and not much more than a life sized Erector set. It gives me something to tinker with and keep me occupied. Cheaper than drugs or other women...at least that's what I tell the wife.

Like that's a bad thing? Styling issues aside, IMHO the two things holding the F-body back are the live axle and the weight. The FD swap solves that (and the styling). Seriously, the handling isn't impared much (if at all). I've had two rotary diehards drive my car (one at an autocross), and both were impressed with the setup.

Yup, no changing that.


Thanks, but that's supposed to be at least half the fun for me. And I have to justify the TIG welder the wife bought for my B-day last year.

It's giving me fits right now with all the packaging constraints, but I'm sure I'll make due.


Absolutely. If you're equipped to test an AWD setup, we can throw the STi on there for a good laugh.

pianoprodigy

Sounds like you've got a bone to pick with turbo setups. The power at a certain boost level will obviously vary greatly based on the CFM of the turbo. I guess the laws of physics are different at your dyno though. You really discounted yourself when you had to throw in the "200 hp shot of spray" comment.

wanklin

iTrader: (2)

I've yet to see a LS1 FD under $20k and I would expect a turbocharged LS1 to sell in the high 20s..


and a modified RX-7 is a horrible investment. I've yet to see a prestine stock RX-7 (keeping inflation in mind) sell for more than it was purchased for new. You could arguably make a little money dealing used cars but any gains will be due to information missmatches between buyers and sellers. With that being said if you are going to spend money on modification you should modify for yourself, not the next owner.

To each his own.

jetenginedoctor

Dude, you're still a tool. When you've got an engineering degree hanging on your wall, then come back and we'll talk. In the mean time, go talk to your dog, he's surely more interested in hearing your thoughts than I am.

jetenginedoctor

Okay, here's an example of why I seriously doubt you'll make 600rwhp with just 8psi of boost (or whatever your guestimate was.)

Yesterday, I dyno'd a Firebird with a fresh 355 LS1. It made 286rwhp and had a nice fat powerband. This is tested in Austin at an elevation of about 500 ft, 80-some degrees, and 55% humidity. The 286 was the corrected number, FWIW. Anyway, ambient pressure was 29.49 inHg, which was a tiny bit better than standard. So, for sake of simplicity, let's look at a very crude perspective of the unlikelyhood that 8 psi will yield 600 hp on an LS1.

Now, this is redneck rule of thumb math, not intended to be exact. If anything, this estimate will err on the high side.

If the car made 286rwhp at roughly standard pressure (14.64 psia) and you increased the charge pressure by 8 psig (22.64 psia) you could roughly guesstimate the best case power increase to be a near linear function of the rise in charge pressure.

22.64psia/14.64psia=1.546 pressure ratio. . . . . or best case of a 54.6% increase in HP if charge temps are unchanged (very unlikely.) This would yield the following:

286 rwhp * 1.546=442.156 rwhp

Of course, this is unlikely, because with increases in HP at the crank, the parasitic losses in the driveline increase logrithmicly. The best I would expect to see in this case on a turbocharged engine is 420 rwhp or 390 rwhp on a typical supercharged engine.

And where do I get the 200 hp shot of spray remark? Let's say that 200 hp shot of spray really is worth 200 hp at the crank. Figure a VERY conservative drivetrain loss of 10%, and that leaves you with MAYBE 180 hp at the wheels. Add that to your 420 rwhp for the turbo (600 rwhp) or 390 rwhp for the supercharger (570 rwhp.) Make sense?

Like I say, I'm a piston guy who wishes he was more of a rotary guy. I find the rotary stuff quite amazing. I'm not posting to **** on Zach, quite the contrary. I'll stand behind what I've said about not making 600 rwhp with 8 psi of boost without a LOT of help. . . . at least not on a real dyno. If somebody wants to prove me wrong, ring me up and I'll provide you the opportunity to do so. This includes Piannochio (especially.) I'm all about claims backed with facts. Step right up and ride the reality train. . .

jetenginedoctor

Sure it would be. It doesn't matter if it's 10psi delivered from a big honkin' air tank plumbed to the throttle body. It's a matter of charge density, not pressure. What you've got to remember is comparing CFM means you've got to have equal pressure, temperature, and humidity. If you've got 25 psia of charge pressure at 180 degrees, it doesn't matter where it's coming from. The differences in how the T67 and T76 will work is a matter of turbine nozzle/wheel combo, compressor wheel configuration, and power characteristics of the engine. You're confusing different turbos having different boost thresholds as meaning that somehow the 'boost' is different. It's not like that at all.

See my earlier explaination. If that doesn't satisfy, bring your car down when you get it finished for a demonstration. I'll even let you make sure I'm not somehow cheating down the test results.

It's better not to ASSUME anything. If it's a chassis dyno you've got, it's wheel HP that you measure, so don't even worry about what the engine would test at if it were bolted to an engine dyno. You simply cannot assign an arbitrary drivetrain loss to any car in any case and use it to derive a crankshaft HP number. Anyway, by your own admission, you're saying that that GTO at 11-12 psi is only making 570 rwhp. That's still not the 600 rwhp that was earlier claimed.

The Peter Starr supercharger system has an air/water charge cooler.

A couple weeks ago, I made a customer's WRX show over 900 whp on his new Dyno Dynamics AWD chassis dyno, just to prove the point that it's possible to lie to the dyno and give bad results. Again, I'm inviting anyone who wants a stab at it to come show me 600 rwhp with either turbo(s) or a supercharger on an otherwise standard LS1.

That's what everyone who owns a modified performance car says, but seldom experiences. If you've got time to wait around for "the right buyer," then you probably really don't need to sell the car anyway. Why not keep it and avoid taking the hit on all the money invested that you'll never get out? Fair market value is what you can price a car for and have it sold within a few days time, not wait for months till a sucker with deep pockets happens to roll in.

Haven't got an AWD here in TX yet. Hope to solve that this week.

wingsfan

See, here's why it's tough to take anything else you say seriously from this point. 355 isn't a displacement you can get with an LS1. They can't be overbored. You either dynoed an SBC, or an LT1/4, or there's something wrong with your story.

LT1-10AE

I think someone needs to brush up on their fluid dynamics knowledge and understand how different turbo sizes work.

J.E.D., I see what you're trying to say, but it's not quite working. Volume plays a bigger role in power output than PSI does.

wingsfan

The volume of air moved is perhaps the most important detail. Size of turbo DOES matter, otherwise you'd just run the smallest turbocharger you could to generate 10psi, and then do something to take the intense amount of heat out of the intake charge.

And show me an engine with an intake charge at 180 degrees, and I'll show you an engine that isn't going to last long.

Sure, I have no problem with that. I'll have to hold the run to 8psi or so though, as I'm starting with a stock motor while I build my "boost" motor. I fully expect to blow that motor at some point, but I'd like to enjoy it for a little while.

Regardless, any number your "superdyno" spits back is irrelevant. If a car makes 600rwhp on one dyno, and 400rwhp on yours, and then proceeds to rip off a 9s 1/4 mile...well then. Same goes for the 600rwhp car ripping off a 12s timeslip.


You're right, I was just taking a commonly accepted drivetrain loss to illustrate that the GTO is well over 600 at the crank, unless you want to sell me that the GTO only has 5% drivetrain loss.

Again, you're right, but as I mentioned earlier, 600 is just a number...a target to shoot for. Anyone that would squabble over a missing 30rwhp, and be "disappointed" in 570rwhp is kidding themselves. And if 600rwhp is that important to someone, the beauty of the turbo is just cranking the boost a little more.

And still I'll point out again that if 600rwhp is the target, you're far more likely to hit it with the LS1 than the 13BREW.

I think the problem here is that very few people who go through the trouble of turbocharging their LS1 are going to have "an otherwise standard" LS1. The car will be cammed, LS6 intake, lowered compression, likely forged internals, etc.


Well, I doubt I'll ever be ina position to "need" to sell the car anyways, and IMHO noone that owns such an impractical vehicle (it's a toy essentially) should do so unless they can afford it.

Why not walk to work, or ride the bus and avoid taking that hit from the getgo.

Come on man, a car's not an investment. Even if the car's rotary powered and you start pouring mods into it, you aren't doing anything to hold the resale value. So maybe everyone else on this forum should stop modding their cars because they're killing the resale.

Wait for a sucker with deep pockets huh? The two LS1/FDs I've seen go up for sale sold for $20K+ within a week or two of posting. Contrast that with the kid who nuked his knee that's been trying to sell a relatively pristine, running FD for $13K for 5+ months.

Besides, I could always convert the car back to 13BREW power (It'd take a weekend or two, max), and then part out my conversion pieces and LS1 goodies.

There's nothing keeping me from recouping a good bit of what I have into the car...except for the fact that I have no intention of doing so.

pianoprodigy

Oh, please don't hurt my feelings by calling me names.

wingsfan

Some redneck math of my own.

Take the aforementioned GTO running 10.6 E.T.s For ***** and giggles assume atmospheric was at a perfect 14.7

570rwhp/1.816=313.87 rwhp off boost

That's almost a 30hp difference from what you've described.

That's on a bonestock motor. No cam. No heads. Stock manifolds.

So, in a perfect world to hit 600rwhp at 10psi we'd only need to make 357 baseline. Think we can find 44 hp from a cam, heads, and ditching the restrictive manifolds? Of course you can.

Does that example mean anything at all? Of course not. Neither does the assumption that because one motor you ran a few pulls on made 286 that that's what they all make. There are way too many variables being ignored here. Maybe the GTO is a factory beast. Or maybe the "355" is a weakling.

We'll just have to wait and see what my car makes on your "superdyno".

wingsfan

Just one more thing to add. And yes...I realize it'sa dynojet.

http://www.ls1speed.com/catagory.cfm...ed%20Induction

jetenginedoctor

I'll call the guy today and get the details of his engine. He said it was an LS1, 355 inch, fresh rebuild. It wasn't a SBC, I know that for certain. I didn't get under the hood and make love to the engine, it was a dyno day for the Spokes Autocross club. Take me seriously or not, that's up to you. I'll post the results of his tests and find out for sure what that engine was.

BK

RX-Ben

As was stated before, 355ci is a standard LT-1/LT-4 rebuild size. Because of the sleeve design, about the largest displacement you can get from a non-sleeved/non-bored LS-1 is 347ci.

Moreover, 286 hp from an LS1 is a seriously low number for a bone stock car (even a pre-2001 car with the lesser flowing intake manifolds).(http://www.ls1tech.com/forums/showthread.php?t=307931&highlight=stock+dyno),
However, 286hp is a decent LT-1 number.

Are you sure that you are on the same page with the rest of us?? Did the engine have a plastic intake manifold and 4 coil packs on each valve cover?

And what does all of this have to do with that idea that an RX7 without a rotary has been de-evolved?? Have you ever ridden/driven an LS1 swapped RX7?