Charles R. Hill

iTrader: (7)

If the only issue is the strength of the factory links because of power-adding upgrades, I would suggest the you use factory-style links/rods with either thicker walled material or stronger material altogether. In my opinion, the only reason you would want to use Heim joints on the rod ends is if you are going to drastically alter the rear geometry for special applications such as strictly drag racing. I would like to think that solving Manuel's and Robert's problems with bending the rear links is as simple as reverse engineering the factory rods/links in titanium and using urethane bushings. That's my plan in helping them, anyway.

stickmantijuana

rgonza, i've read around a few forums and articles regarding the BMW E60 SMG tranny. while it seems to be this tech marble, it unfortunately seems to have a very low reliability across the entire board. i've read everything from hydraulic pump failure to actual gear problems, and that's from the 550hp engine. i don't think it'll last very long w/ our 700+hp engine.

just my .02

rgonza

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Hi,stickmantijuana Thanks for the info!!!! i've hear that this trans hold about 600+ without no mods. Here we no have problems trans electronics and mechanicals for trans fitting to RX8 a friend of mine have one those trans SMG E 60. But thanks a lot for the info. now i going to work with the G force t56 tranny.

Charles R. Hill

iTrader: (7)

Stick, I don't know what your end-goal is, in terms of power output from the 20B, but I wonder if there are similar comparisons that could be made by looking at what people do with modded SVT Cobras, Vipers, and other H.O./modded independent suspension vehicles(?). The factory RX-8 rear suspension will be fine up until a certain point(which has been somewhat discovered by our friends here). Beyond that one could simply strengthen the factory set up or go with a new fixed-axle conversion. The point of urethane/nylon bushings isn't necessarily greater durability, although that is a small part of it, it is less deflection under load which helps to keep things under control. My own opinion is that Heim joints are also not necessarily stronger but they allow for suspension systems to be adjustable while also keeping strength. I would point this out; if the rear suspension needs no further adjustment, would you rather use nicely welded eyelets to hold your bushings in or Heim joints that must also have threads cut into the rod/link? Here's the thing for me-on this website we have friends who are pushing 500-800 rwhp and only now has the rear suspension shown its weakness. Unless you plan on going higher than those levels why complicate things and spend more money than you need to just to have a suspension that offers nothing over the factory 5-link? One other point about shops(not to disrespect your chosen shop)- many of us out here are not too quick to admit when we don't REALLY know the definitive answer to a specific question and, instead, rely on that which we have always done. The RX-8 and your given application are rare enough that nobody knows, for sure, what is absolutely necessary. As was pointed out previously, get the 20B running and then worry about the suspension as it becomes necessary. Besides, in the meantime I may have a titanium 5-link/urethane bushing kit available and the PR guys may have it well-tested by the time you need to do something about your own. If my kit proves to be the solution and it simply bolts in, why not wait and see how it goes? My theory about modding things is to stick as close to stock/factory as possible until modifications only become necessary and not merely theoretical.

stickmantijuana

charles,

my goal is a daily driver w/ 20b pushing around 600-700whp.

i autox probably every month & take her on a track whenever i can. i've never gone to drag strip yet. i was debating between 13b & 20b..., but i figure i live only once so what da hell. so that brings me here today

well i think the shop's reason for going heim is the inherent weakness of the bushings. i asked him to build me a car that'll last 4yrs w/ just oil changes between fill-ups. i don't mind getting bushings replaced every year or so, but wouldn't want to do it every month. i guess that would all really depend on how hard i would run it.

i think i'll be reading a little more about the issue... seems to me the suspension choice can really be a toss-up and would largely depend on different individual preferences. from what i gather so far, heim seems to be a bullet-proof choice w/ the higher maintenance requirement, and upgraded bushing & housing seems to be the cheaper & more comfortable replace-as-you-go option. how long would bushings last w/ 1-2 full throttle per day? haha odd question, but wanna give it a shot?

stickmantijuana

anything for u! they say bmw is coming out with a new manual tranny for the 07 (not SMG). there are bunch of e60 owners waiting for that swap as we speak.

is sequential tranny generally less reliable than the H-boxes? i wouldn't imagine so, but i figure the current bmw smg would be the epitome of all sequential boxes... ah the decisions decisions...

stickmantijuana

http://www.m5board.com/vbulletin/showthread.php?t=78530

there's a short list of some of the bmw smg problems.

my burden was too heavy, so i wish you can make your own decisions from the original source would love to see an e60 smg on rx8 though!

stickmantijuana

btw, the shop i'm going w/ has lot of experiences w/ 20b installation into rx7. do 7 & 8 share similar if not the same rear suspension geometry & linkage? if so, i assume what he learned from the rx7's would transfer quite well to rx8.

Charles R. Hill

iTrader: (7)

When I first contemplated putting nitrous on my RX-8 I spoke with a few shops in my area that were said to have a lot of experience with rotary engines. They all told me that I would blow the seals out on the Renesis when I used the nitrous. This was back in April of 2004. I think it was in July of that same year that I first installed my nitrous system and began testing the limits of the Renesis. I discovered several things, but the most important was that the shops I spoke with had not even had a chance to touch any RX-8s and, therefore, were assuming that the Renny had the same inherent problems that previous 13Bs. Secondarily, to reiterate a previous point, rather than these shops admit that they hadn't a clue as to what the Renny could handle they just insisted that the RX-8 and nitrous were not a good match. We all know what the truth is regarding that concept. What I am taking much too long to say is that the RX-7 and RX-8 have different suspension designs and any weaknesses the two might have are probably way different. Unless this shop you are dealing with can say that they have a bunch of experience with the RX-8 they are as much uninformed as anyone.

As far as 600-700 ponies in a daily-driven car that sees monthly autoX action; that might be a bit of a contradiction as even a 20B with that kind of power will require more severe service intervals than what you are hoping for. If you were to keep your goals in the area of, like, 400 h.p. you might have a much easier time achieving them. I am not sure what experience you might have with different weight/power ratios but 10:1 is good enough to get anybody in trouble either on the street or at the track. If you were to turn the boost down for daily driving and only hit the 600-700 mark once in a while you also might have a much better time driving the car as it, again, would require less tinkering.

There was a guy in my area who thought he could easily handle 440 h.p. in his 350Z. When he picked his car up from the shop he damn near killed himself by flooring it when he hit the street. he got a rude awakening as to just how much power 350-400 lbs. of torque is in a 3K lb. car. I hope your goal of 600-700 h.p. is an informed one.

BTW, this past summer I had a customer who took his '85 RX-7 to both a dealer and an independent shop because his car wouldn't start and, when it did, didn't run well at all. Both shops insisted he needed a rebuilt engine for $4K. He heard about me through the "grapevine" and let me look at his car for him. I discovered the distributor was out of alignment and a $30 vacuum hose for the secondary valve was leaking. After I replaced the hose and re-installed the distributor I was able to give his driveline a good "once over" and had a practically brand-new driveline for $1,340 out-the-door. When I called my customer on both my 7-day and 30-day checkups he reported that he couldn't believe he was driving the same car that had to be towed to my house. My point is that every shop is different and has a different agenda so be careful when counting on the advice of others.

stickmantijuana

thanks for the advice. yea i realize that 600whp is quite handful for the rx8, but the only time i'll probably be using it would be next to superbikes on turnpikes. i drove the new z06 a few weeks ago and i thought it felt really good. yea.. apples & oranges, but i thought 350-450whp would feel pretty good for our 8. btw, reason for not going w/ 13b is something i'll have to wrestle w/ until i can make the money back.

as for the shop, they work w/ rx8's all the time. it's really no secret, and i don't know why i didn't mention the shop's name. in any case, i'll probably start another thread for the 20b install if the shop wouldn't mind taking pictures of it. i'll be telling the shop to locate the motor tomorrow!. hope all will go well!

in the meanwhile, i'll take any advices & inputs you may have.

damstr

Wow I was worried about keeping the RX-8 for a long time any not being able to make it really fast.

But now I see this thread and have lots of hope. Pretty crazy stuff you guys are doing. I searched through some of pages for vids but the first couple don't work anymore. I'm dying to see what this thing is capable of.

So doing a complete engine swap with the specs listed in the first post + any upgrades to the tranny to put up with that kind of power, after labor and all is about $12k if I had someone do it? Are there different models of the 20b? If so which is the best/most reliable?

Again I searched through some of the pages for this and saw someone said $7500 but I wasn't sure what that included.

And for a daily driver this is really reliable with 650+ horsepower? I definately have the money but it still has to be a daily driver for me.

Sorry for all the question, I'm totally new to the 20b engine.

Thanks soo much for anyone that helps me out here.

stickmantijuana

w/ 600whp, can i floor it w/o worry of loosing my back end once i'm above sayy... 50mph? or do i have to gentle it in? i mean, at which point would i be able to use 600whp?

i lost my back end once on the freeway and i gotta say that almost killed me. btw, rgonza, your videos are down... could you upload them to google?

epitrochoid

i can break the rears lose at 65mph with just 276whp...it's all about dealing with those limits, or building the rest of the car to handle it

rotarygod

With 600 rwhp you can probably break the tires loose at 150 mph! 600 hp quite frankly is a waste of time on a street car and has no place being driven on the street. There comes a certain point where more power does not make you any faster due to traction limits and all you are getting are bragging rights, dyno charts, less reliability, and more potential for disaster.

stickmantijuana

epi, when i drove the z06, the tires didn't break loose after about 30. maybe it was the tcs. besides, i have 290-300rwhp right now and can't break the tires after 20mph unless i drop the clutch. i should mention i have 285's in the rear.

i thought it's the torque that breaks the tires loose, not so much the hp. maybe i'm wrong. i also may upgrade to 315's for the conversion but probably would stick with 285's for now. i would think i could put down 500-600whp unless i'm delusioned by some unforeseen factor. i will be stepping down to 3.9 as well. what would you think is the max the rears can put down on a straightaway? w/ street tires, on a fairly clean freeway, etc. i guess i'm looking for somewhat informed subjective opinions.

Charles R. Hill

iTrader: (7)

Let's not get into the "strawman" torque vs. h.p. discussion!! If I remember, the ZO6 has 325's or some other huge size tire on it and that's probably why you have the same decent traction, with 285's. BTW, what is your offset? As I get closer to my goal of 11.7-11.8 in the 1/4 mile I will need wider wheels/tires myself.

OneEvilRx8

robert don;t forget to put down the dyno charts for the renesisturbo rx-8 that you guys are making!!

evil

RX8PR

The proyect is already 80% finished ...........
He started the car last Sunday.

Manuel

RX8PR

Who whants to race?
check this truck!

Manuel

OneEvilRx8

oh, my god... what is that?

RotorManiac

oh, my god... who is that...



...lucky bastard ?

RX8PR

I love to see those trucks running on the race track, they are fast!


Manuel

GrRx8MaZdA

Hey Rob+Manuel.
What brakes do you use?
I will be going custom turbo for 400whp with motec and single turbo(90% motec not sure yet) andmaybe change fuel lines and everything.

From suspension i have greddy struts front+rear,HKS Hypermax Damper 2 and i am going to buy also the Autoexe under member brace.

For braking i have the 6pot front big brake kit from Grex-Greddy...But for rear nothing..Should i buy something for rear or the front is enough??What do you suggest me to do??

RX8PR

For a goal of 400 hp you would NEED to change the fuel lines and fuel pump.

In our cars we use two fuel pumps one primary and the secondary pump enters to work from 3,000 rpm's.....................

We use the factory brake system............................
Before make any other change to the car first make the custom turbo and them
see how the car handles with the new modification. You can save some $$$ that way............

Manuel

GrRx8MaZdA

Hey Manuel if you can pm me exactly what i ll need for the fuel system upgrade...pumps,injectors etc etc...Please..