mysql

Most people make threads about going from NA to turbo, and they rave how great it is. Of course going from 130 tq up to 200 or 300 torque will feel like a huge difference. No matter which FI kit you get, it will feel tons better than when it was stock. So I look at those new user reviews with a grain of salt. They will always say how great it is.

On the other hand, when people go from FI to NA, they tend to either be selling off the car, or are disillusioned because something horrible happened, like blowing the engine. So we either hear nothing, or they are down on the entire process and say it's not worth it.

I'm currently NA because my exhaust manifold had a tiny crack in it. So the manifold was yanked to get repaired, and then ceramic coated. It will be done next week, and will be better than new.


Still, it's interesting to note the difference between NA and turbo....

For one, people talk about turbo "lag". Yet on a stock car, you need to get to around 5k before the car feels like it's pulling. With the 3071R turbo, you need just under 3,000 rpm to spool to 12 psi. So from my viewpoint, there is less "lag" on a turbo RX-8 (with a properly sized turbo) than there is on a stock RX-8. You hit the throttle and you're speeding away like it's nobody's business.

Having been FI for 2 years, going back to stock has had some interesting results. Yesterday on my drive home, there was a white van in front of me on the off ramp lane. I decided there was enough space for me to floor it, go around the van and be in front of him. Unfortunately I was dead wrong. I couldn't accelerate fast enough and I ended up being boxed out of the turn lane because the car behind me also accelerated. So long story short, I ended up having to miss my exit and my drive home took an extra 20 minutes.

As I've said in the past, the best way to describe the acceleration in the 3071R is that 6th gear is similar to a stock RX-8's 4th gear. So my 4th is like your 2nd. With 250 torque available at 9 psi, you can see it's quite easy to double the 130-140 torque on a stock car with just a bit more boost.

Another way to describe it. Imagine you have a rubber band in your hands. On a stock car, the acceleration feels like you taking the rubber hand in both hands, and slowly pulling it apart. You feel like you're pulling forward slowly then you get slingshot at around 5k and it's a fairly level amount of acceleration from that point onwards. With a turbo it's basically the same till 3,000 rpm, then it's like a sumo wrestler just kicked you in the ***.

It's also highly configurable. There is no drawback in terms of powerband delivery. If you want a linear powerband, you just need to tweak your boost controller. With greddy's profec B (one of the most popular BC's ever made), you can set stuff like "boost consistency", which basically defines how quickly spool takes place, and if it climbs early, or late, and how fast it drops off at the upper end. So if you wanted a "SC"-like feel, you can set it to slowly boost and level off, or slowly boost and keep climbing. It's all configurable! The only thing you can't tune out is an oversized turbo taking too long to spool. But that's not an accidental choice. If your turbo is incorrectly sized, it's your own damn fault for picking it.


Besides the torque increase, a FI rx-8 feels just like a NA one. The exhaust is muffled more, but that's about it. Even your fuel economy will be about the same.

There's always something to be said about easy hp gains. With the stock setup there are only a few things that can give you gains in 5hp increments. Turbo changes everything.

I also wanted to mention that power gains are difficult to judge. People constantly say they can feel 5 or 10 hp. Even 20 hp can be difficult to properly tell. Of course, going from 270 to 290 was noticeable to me, but it depends on where in the powerband you get it, and how quickly the change is made. If it's a dyno tune and you get the change within an hour, you'll remember what it was like before. But memory can be a funny thing and when I had coil issues, I knew something was off, but I didn't realize I was down over 50 whp!


So is going FI worth it? If you have the cash to blow, hell yeah it is. What kind of stupid question is that?

jdoo

Thanks for the post.
It sounds to me like NA is definitely the way to go since it results in more seat time in your 8!!!

mysql

I wouldn't have minded too much, but on that extra 20 minute ride there was a semi (hauling rocks) a few cars ahead of me and I heard a few thunks. I didn't find any scratches, but I would have preferred to avoid the experience.

Schimmle

I love this post. It nice to actually hear this. Like you stated in your post its always the other way around about people taking them off and selling them. This makes me feel better about going FI. Thanks dude!

onefatsurfer

dang.. now i really wanna go turbo...
oh, if only I had the money......

.........on the other hand, couldn't you just downshift to 4th to get past the truck? the shifting is a big part of the fun as well!

neXib

People who talk about turbo lag aren't exactly updated. There's a lot of different characteristics to turbos, so I'll agree that it's silly to talk about turbo lag.

I'd love to have a turbo one day, but not really allowed to since my car is an import

mysql

That WAS with me downshifting. I misjudged thinking I could make it. I didn't realize how slow the car would be. I'm completely used to hitting the gas and instantly being well over 100 mph. With NA it's hit the gas and wait... wait... wait for it... ahh. Now I'm going fast.

Watch this:

http://youtube.com/watch?v=a0RSPGoHgbw

In the last clip, I'm going from ~47 mpg to 75 mph, then back down (cause the car in front of me was hitting the brake)

Jasonawojo

iTrader: (2)

But, when NA, acceleration is a whole dramatic event!! I love flooring it in 6th

paulmasoner

iTrader: (1)

Ah, you just answered my PM with this tread

cool beans man!

Cattywampus

I forgot what NA was because I haven't driven my car in over a month. FI will be soon and can't wait for my comparisons. Good post.

paulmasoner

iTrader: (1)

if by dramatic you mean: there is some allusion to speed and power, then some foreshadowing, more foreshadowing, then you finally hit it!!!, ahhhh, and just like a hyped up movie, it was good, but at the end you are a little disapointed in how it turned out

db_8

this might be off but since you got the MM turbo, is there fitment issues if you're using the stock front bumper? i usually see the MS kit or some other kit if they have FI mods *thinking of a sleeper mod..*
choosing between FI or appearance (go vs show)

gregs

iTrader: (7)

i totally agree i went from turbo to n/a due to having drivability issues i didnt have the time to troubleshoot, but small things like passing cars and accelerating is completely different between the two, sound was alot quieter with the turbo installed and now, cant wait to go back to having my turbo installed late this year

mysql

bumper choice shouldn't matter. Nothing extends out that the stock bumper couldn't handle.

The only thing about the stock setup is the vents for intercooler and oil coolers aren't as big as compared to the MS version.

robrecht

Nice thread, mysql. Do you have any internal engine mods? Is it possible to turbo a Renesis to your extent and make it bullet proof? Or do you just accept the risk of blowing an engine every now and then?

mysql

With proper tuning, the risk of damage really isn't that high. 12 psi and 350 whp is not extraordinary. I went 2 years without issue till I had detonation from an ignition upgrade. I had no problems before the upgrade, or after I removed it. This only goes to illustrate that one shouldn't be quick to do upgrades till they have months of public use without problems showing up. Even then, at 12 psi, all that happened was a small crack in the front iron housing. Unfortunately it couldn't be ignored since it spews oil. It was not cheap to fix.

If you want to push for 400 whp, and 17 psi or something in that range, you'll be playing with fire and have to accept there is a chance of issues surfacing.

robrecht

thanks. Yeah, I read about your coil-related detonation. sucks. So no internal strengthening of the Renesis?

mysql

nothing to strengthen and not much to port. Pining the engine was really the only thing that might be done, but I'm not going to be pushing it hard enough for that to be a big deal.

robrecht

Thanks. Sorry for my ignorance, but what is pining the engine? I've read of people installing really expensive ceramic apex seals but glad to hear that's not really necessary for bullet proof 300 hp/250 tq.

MazdaManiac

iTrader: (3)

Great thread, J.
Very well written and a good perspective that most of us won't/don't get to experience.

quazmosis

iTrader: (2)

Nice write up.

Brettus

iTrader: (2)

Funny thing is - on certain roads I find the amount of power I have N/A is plenty . It's really only on the track when everything goes past me down the back straight that I'm wanting for more ....
I really think a lot of people who turbo their 8's have no idea what it takes to handle a car with that much power

alienRX8

Yeah this just makes me want to go turbo even more. Thank you mysql for making me want to spend money in these harsh economic times haha

db_8

^+1

kersh4w

iTrader: (3)

so now that im thoroughly jealous, you want to give me the money to get turbo'd?