I think the point being argued, is that "the ls1 swap doesnt ruin handling". Though I agree a more fair comparison would be a stock FD w/ AC, PS, ABS vs ls1 FD w/ AC, PS, ABS

And as for 100 more whp, we both know at most autox courses, that 100whp wont help you much if at all. Its all about driver, and suspension setup. (see: why stock miatas dominate)

 

that is so true. most people who have never AX'ed won't agree, but its the truth. HP doesn't mean much on AX. his suspensions is so much better than mine; we should have swapped cars a few times and posted the results. we keep in touch now so i bet we will do that next time (next season ). and my lack of ABS (in addition to not having a good suspension/tires) was a total killer. hello flat spots

 

so lets say i go to an autocross with a nice stock 95 R2 FD. i do ok and consistent, then i slap on 100 more whp, you dont think i'll do any better?

i say compare a gutted 400whp LS1 FD to a gutted 400whp rotary FD.
a 400whp ls1 FD with no AC/PS/etc vs a 230whp FD that weighs more and has all the stock AC and PS isnt going to be much of a comparison.

 

Honestly? No. Not unless you also put on much larger, stickier tires, along with upgraded suspension, AND upgraded driver. Sure, you can get moving ALOT faster in the straights (what straights? Its autox) but you cant slow down any faster since you kept stock brakes, and the ability for your tires to grap the pavement to slow the car hasnt changed any. This will lead to braking earlier than before, which leads to wasting time. You certainlly cant turn any faster due to extra HP.

For another direct comparison that is easy to find (since FD's arent all that common locally to us) look at the times of stock miatas vs SM2 miatas NOT on race rubber. The SM2 miatas are actually slower alot of the time because its not as balanced a package and leads to spinning/drifting alot of the course, which we all know is the slow way around.

I didnt see 2 seconds worth of time on that autox course where that extra power could really be used. 2 seconds is a LIFETIME on an autox course.

 

edit: ok i'll buy that, but you're not going to convince me that having extra power and torque (especially v8 lowend torque) isnt going to help you accelerate out of a turn faster...

 

Absolutely you'll go faster but not near as much as you think.


If you put me in identical FD's but one had 100 more horsepower than the other of course I'm going to go faster in the more powerful car. It will most certainly not be 2 seconds on a 55 second course though! I'd say about 1 secondish at most unless it's a poor course design that favors powerful cars.

Remember that a stock FD is not underpowered so adding another 100 hp to it won't make it rocket that much faster. The additional power only comes into play at the points where the throttle is already on the floor and there are typically few of those. If you put 100 more horses in a "slow" car then sure you'd see bigger changes, but not so much in an FD.

 

i donno who's car you are describing, but a poor tune or a busted stock car is not a very good example to me. if YOU cant build a 400whp reliable rotary that doesnt suck drivability wise then thats your problem. many more 400whp rx7 blow is because the owners or the shop that works on them should be a butchery and not a performance shop, while a 400whp ls1 is almost stock. yes i agree, and kumhos are stikier but the a032r are not that much behind. if you consider a032r with 60 tread wear a street tire then the kumho is just as much of a street tire as the advans. the weight is similar and the weight distribution is "better" and i have a very good feelign that, the R1 was touched. didnt the r1 have a adjustable coilover setup, with suspension like that it is very important to corner weight it, that is the whole point, if he didnt then that could be a reason why its off on the sacales. it DOESNT destroy the handling, but i can sure as hell see a diffrence from that to a stock fd, if you cant then you are just not going fast enouf.


what i would really like to see is the driver of the ls1 fd drive the r1 as that would be a more fair comparison to the timed runs. its all about the driver in autox AND about low end torque. the ls1 has an advantage even over a seq turbo fd, both in throttle responce at lower rpm and higher tq output, you cant argue that. but a car with suspension and one without given the same chassis, the car with suspension and 180less hp should be closer in times to that of the stock suspension car, that is why i brought in the driver argument. the reason you see a lot of sm2 miatas do worse then the stock ones, is because the stock ones are setup by mazda, who know a thing or two about how to make cars ahdnle and drive nice, as to where the sm2 cars have parts thrown on them without being properly tuned will net slower times. ofcourse there are those who understand what they are doing and can make the car turn a faster time at autox course with the aftermarket parts tuned properly to take advantage of the chassis.

 

thank you.

 

What I'm talking about is... an LS1 with high horsepower for a streetable FD (i'd say around 400whp. That's not far off, is it?) is MUCH more everyday driver friendly with smoother start-up, better gas mileage, and I'm sure much better reliability than a similarly powered Rotary. I don't know many 400+whp rotary FD's that run super smooth, especially on start-up (that was my point I was trying to make). Also most rotarys pushing that much power run some sort of premix oil in the gas just to be safe. I don't really see how that's hard to understand. Just because an LS1 w/ 400whp is near stock doesn't make it bad. It's not my fault it takes a lot more for a rotary to make that much power (atleast somewhat reliably)... that's just how it is. So you saying that a 400+whp rotary is more/similar reliable/streetable than a 400whp LS1 is super hard to believe. Sorry. This argument sucks anyway. Can't everyone just get along. I mean we all own the same car. Both types are sick. I don't think anyone here was trying to make the other look bad so people should just lighten up a little bit.

 

Everyone should get along. This forum is here for people around the world to talk about a car they share a common interest in. There is a ton of info here. What people decide to do with their cars is entirely up to the owner and should be looked at openly, for the simple tool of gaining knowledge.

A Rx7 owner is usually someone who thinks outside the box. A timeless body style and a rotary engine almost make it exotic. I love blipping the throttle of a ported ceramic seal engine. It just has that one of a kind sound. To me a big V8 or ls1 is too common among new and old cars that share the road ways with us. It is great that Chevy has developed an engine that is cheap, can make big numbers, and is lightweight. It is even better that it can be placed so neatly into a rx7. Even though you are thinking way outside the box when you do the swap. You lose some of the exoticness of a rotary. Regardless, if there are more rotary rx7s than ls1. Some people care some people don't.

Most people don't have the money, patience, or understanding to maintain a high horsepower 13B. It is not designed to be a everyday engine when you start breaking into the 400-500 hp range. It is a race car at this point. Some people can make it a daily driver, its up to the owner. With the cost of a used 3rd gen going down more people can buy them and blow them up. Not to many willing owners out there, to have many reliable high hp rotaries. Obviously, a stock 400hp V8 is a different breed and can be a better all around daily driver and have better low end torque. So it becomes something more well known and an easier way of making the car better suited for the owner. Either way, everone has fun.

SMCHPWR, thanks for the corner weights of your ls1 3rd gen. Maybe some more of you guys will do the same and we can start a thread of just corner weights of ls1 vs. 13b 3rd gens. Who can balance better? With what mods? I will post corner wieghts by the end of the winter.

 

I have since lowered my right rear but before I did so my mostly stock FD weighed in as follows:

Here are the results with a 180lb driver in the car:

Left Front - 792 lbs
Right Front - 697 lbs
Left Rear - 732 lbs
Right Rear - 712 lbs

Or for those who like graphics:

792 | 697
------------
732 | 712

This amounts to 50.7% over the front and 49.3% over the rear

So if I substitue my FD data into the first post of this thread it would read:

--------------LS1 ------- Rotary
Left Front: 684 ------- 792
Right Front: 695 ------- 697
Total Front: 1379 ------- 1489

Left Rear: 705 ------- 732
Right Rear: 645 ------- 712
Total Rear: 1350 ------- 1444
TOTAL: 2729 ------- 2933 (2753 if you remove the driver's weight)
% over Front: .505 ------- .507
% over Rear: .495 ------- .493

I don't know if the LS1 FD was weighed with the drive in the car or not as that could make a big difference.

My car, a 1993 touring model with nothing removed, came in at 2753lbs once you subtract the driver. The only things I have done that reduces weight are a complete aftermarket exhaust (downpipe, HF cat, RB catback), removed the spare tire, relocated smaller battery & the AD shock are much lighter than the stock shocks.

I think that what one has to realise is that corner weights can vary a lot from FD to FD depending upon the suspension setup as well as where weight is placed in the car. The FD the LS1 was compared to in the first part of this thread probably had suspension that places more weight upon the front. Or maybe a heavy front mount intercooler?

Anyway... just though I'd plug in my cars data for comparison.

But regardless... I think it is impressive that a 5.7 liter V8 engine can be put in the FD without upsetting the balance. Very nice.

 

Thanks john, that is good info also.

No driver in the car. I will post up with me in it later tonight because I do have that info also.

Maybe, I don't know, but its koni's with stock R1 springs. Stock intercooler.

Thanks!!!

 

I've never raced at Meadowlands, but from people Ive spoken too its very fast and long compared to what the courses they run at E-town. A friend of mine raced there in his 300ZXTT and said there were parts he could hit 3rd gear. I'm in no way bashing you or the whole LS1 conversion. Just wanted to confirm if the course is really like that, and if any, a higher HP car could have a slighter edge towards a car with lower HP and almost the same handling characteristics.

IMO, I would most likely never do this conversion and not because I dont like it. The reasons are I just love the way my car sounds(sequentials with DP, HF cat, and catback). I think its a more unique car because of the type of engine it has and currently Ive never had any problems with it. I have 50K miles and its not my daily driver so Im not concerned about gas mileage. You could say that an FD with an LS1 is even more unique, yes. But mainly it would just be my preference to keep it a rotary and not change anything. I can definitely see people who have been through multiple engines and want something different and dare I say, more reliable. To each his own I suppose. Id sure like to ride or even drive an LS1FD tho!

 

I'd just like to say that I totally agree. I can understand why people like rotarys more than LS1's in their FD. There are definitely plenty of really good points on each side! :-)

 

Damon,
This seriouly surprises me and I don't do much autocrossing however spec miatas are nowhere near the FTD at the events I do attend. I'm talking 5 seconds back.\

I'd think with another 100 rwhp the spec miatas would be setting the FTD.

Help a brotha out,
Fritz

 

I was speaking in regards to adding 100 hp to an FD. An FD is not underpowered on an autocross course so giving it 100 more horses won't make huge gains in time. A Miata on the other hand certainly is underpowered and giving it 100 more horses would see a much bigger gain in time than the same power given to an FD would.

On a roadcourse more power is always better because there are straights, but jacobcartmill's question was phrased specifically about stock FD's on an autox course.

Make sense now?

 

with me in the car:
754 | 704
785 | 687
ttl = 2930

if too lazy to check first page without me in car
684 | 695
705 | 645
ttl = 2732

 

HEHE

I'm with you now.

2muchpwr needs to drive the other guys car and the other guy needs to drive his car. Peronally I still feel that 100 rwhp will make a big *** difference on a 60 second autox course even if you're driving a c5 or 6.

Actually a high horse power car is much more difficult to drive so the other guy won't have a chance when he switches cars LOL

 

From what I understand, premix is only a preference, with benefits, not a MUST. And about that whole 400hp rotary reliability dealie-wop, I've sure you've seen this a few times on the forum. "Fast, Cheap, Reliable: You can only choose 2 of the 3." But in a sense, that "formula" can be applied to ANY motor in existence. Reliability isn't a problem if you've got the money to back it up. What is "streetable" is also a person-to-person opinion. In the end, a well put-together car is a well put-together car. And I must say... "What a well put-together car!" Now if we could only get our local Z06'd FD, owned by GsrSol, out to the AX.

 

you guys neglect to remember the weight is now higher and farther out rather than low and center like the original motor...

 

Prove it. You negleted to post the location of the CG for a turbo rotary install and for an LS1.

The scales don't lie; the two cars are close. Don't let the anti-piston crowd turn you into one of the bleeting sheep that keeps repeating myths.

 

Well... it does seem to me that the rotary would have a lower center of gravity since it doesn't have cyclinder heads and a valve train sticking off the top. Of course I can't prove this with any hard data... but it seems logical.

 

Turbojeff and I did that exact experiment back in Spring 2004

https://www.rx7club.com/showthread.p...0&page=4&pp=30

Start with post #91

 

The heads are essentially all aluminum and are relatively light... composite intake weighs about 10lbs... the main weight I believe is the block/crank/rods which sits pretty low. I think the 140lb T56 helps to balance the conversion out a bit. My long tube headers must weigh an honest 5-8lbs each.

 

The front rear distribution will be independent of suspension parameters, and only based on the car's F/R cg location.

----------------

I enjoy my still-sequential FD, but can appreciate the fun an LS1 FD would be, with neck snapping throttle response. ( and it is better than totalling FDs, as some do ...) Mabe a dry sump to lower the cg.