Turbo or swap for track day - RX8Club.com

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Turbo or swap for track day

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Old 08-01-2018, 09:25 AM
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Turbo or swap for track day

Hi,
I read a lot but I can't find any clear answer.
I use the car just for track as a training one. The project is so advanced that sell the car and change platform is not an option.
I need more hp. The options are :
  1. Turbo.
  2. Swap with 13B REW Turbo already in an Rx8 I know (with adaptronic, gearbox, cooling, etc.) plug and play. They claim 500hp but I'm not sure the build is track minded.
  3. Swap with some v6 engine.
The goal is to have a reliable car that don't blow up every 10.000km.
About track condition: two weeks ago there where 37C and I was stuck due to differential oil temps exceeding 150C that blocked it (hopefully with no damage. Probably due to the final gear that add more heat. So I need a radiator and a pump...).
I always had temp problems, just this year with the HPI radiator and the SPAL fan things seems go a lot better.
I think the AEM is really badly placed and it is a major concern on water cooling.

What I did not found is some serious feedback on turboed rx8 seriously tracked.

Just to give you an idea about the car :
Interior fully striped out and repainted
Full welded roll cage
2 Sparco seats with 5 points seatbelt
OMP wheel
Electronic circuit braker and automatic fire extinguisher
No air co, No air bags, No air pump, no radio etc.
VDO gauge oil and water temp, oil pressure.
BHR decat
Wiring harness simplified (7kg less)
Lithium battery
AEM CAI and ECU mapping
ATC flywheel and counterweight with Exidy stage 1 clutch
Sohn, remedy water pump-oil pressure regulator-main oil radiator-water thermostat.
Thermal pellet bypass
HPI double core radiator with a single custom fitted SPAL fan.
Ducted air to the radiator with a custom made duct.
Front brakes ducts.
Goodridge brake lines and clutch line.
2 pieces girodiscs 4 corners.
DTC-60 4 corners or Carbone Lorraine CL RC6e.
Ohlins coilovers.
Silent blocs on 4 corners.
Oz Ultraleggera with slicks.
Os giken super lock LSD, 4.77 final gear, powerflex diff mountings.
Progress Tech F/R sway bars.
Lateral and rear windows in Lexan FIA approved.
FG front and rear bumpers, main doors, trunk.
OEM hood lightened.
Aerocatch on the hood and the trunk.
FIA rain light.

Thank you in advance

Last edited by vcoil; 08-01-2018 at 04:04 PM.
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Old 08-01-2018, 09:59 AM
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Option 2 sounds like a good next step. I was going to suggest 13b-REW swap, but if you already have a plug-and-play solution with a 13bt, that seems like a no-brainer. I'm not sure what 'track-minded' means there.

Otherwise, someone posted here recently about their LFX V6 swapped track toy. Looks interesting, maybe he can give you more info.

I wouldn't worry about the AEM's placement, but if you haven't already, rip out the A/C condenser.
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Old 08-01-2018, 04:09 PM
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In fact it is a REW, I changed the post.
AC ripped out years ago .
Thank you for the info.
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Old 08-01-2018, 09:42 PM
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I think your first option of turboing the Renesis defeats one of your core goals of achieving something that's reliable. Without debating or speculating how long the engine is likely to last, the fact is turbo charging any non-factory turbo engine will significantly increase the likely hood of premature failure over its non-turboed counterpart. Clearly from your comments you know a normally aspirated Renesis motor already has a well deserved reputation for being unreliable....

Have you considered an LS swap?

An REW swap isn't straight forward and presents some challenges, as does the LS swap, but when I did the numbers the LS swap worked out a lot cheaper with greater availability of new and old parts. But if you're really fixed on the idea of the car being rotary powered and you can buy an REW that is already set up for an RX8 and is a drop in and bolt up option, that may be a good solution. However I doubt that it would still be a cheaper and cost effective solution ($'s per hp) longer term, also considering the reliability and maintenance aspect as well.

The challenges with fitting a V6 to an RX8 will likley be the same challenges faced with fitting a V8, so can't see any advantage of fitting a V6 over a V8, unless it's got to do with the class you're running in at the track.
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Old 08-02-2018, 07:14 AM
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I'm open to any solution, concerns are:
1) Availability in EU.
2) Weight distribution : seems to me all these swaps are more for drag racing than other. My car already has this weight distribution (in kg, with 60kg driver and half a tank of fuel):
FL 346 FR 320
RL 307 RR 289
I think adding a turbo will add something around 20kg am I right?
A REW is something around 299lbs I think.
Following this post the rx8 dressed engine some says to weight 297lbs = 135kg the LS1 someone here say
On another board a complete LS1 was weighed with all accessories, starter, flexplate, wiring harness, PCM, exhaust manifolds with cats and it came to 480lbs. With headers you could drop an easy 20lbs if not more. It is very light for a V8.
480lbs = 217kg avoid the cat -10kg and pcm and wiring harness -5kg is 203kg means 70kg more on the front and maybe over the wheel axle.
The GM lsf V6 (also I think not possible to easely find here in EU) is
I finally had a chance to weigh the engine. It had the alternator bracket on, but no alternator. Everything else was ready to run on the motor. Composite intake weighs almost nothing and there is no exhaust headers because it's built into the head. Anyway, it was 324lbs (147kg)
.
I know someone in EU that made a 2JZ swap but not in a track car.

How will drive the car after a v8 swap?

Regards
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Old 08-02-2018, 12:10 PM
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I doubt anybody but an actual racecar driver would be able to tell the difference in handling between an '8 with any kind of 13B and an '8 with a properly setup LS.

Just make sure you pay attention to bump steer and update the suspension and corner balance for the new weight and the added power will overwhelm any loss in handling in terms of lap times.
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Old 08-02-2018, 03:25 PM
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As I am (amateur but still...Nürburgring, 3x 25h of Spa, and other endurance racing, but in car with similar power as the rx8 and similar handling but w/o any power steering, ABS, brake assistance...).
I'll add that I would like to have a dry sump and install an electric water cooling pump.

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Old 08-02-2018, 11:02 PM
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An extra 70kg in front of the struts/front axle is very noticeable. Anyone that has an interest in cars and driving will feel the difference. You can notice the difference between driving alone and with a passenger when you drive towards the limits, another 70kg is basically another passenger full time, and one sitting in front of the axle.

I am in the same place as the OP at the moment, My R3 is going to be my street/track fun car and I would like some more power. I still haven't made a decision but I am leaning towards retaining a rotary in the car purely for the handling/balance that the car has with one. My most favourite thing about the car and my FD previous to it was the way it handled, so retaining that feel is important to me.

If we are talking drag racing or highway racing then you won't notice it most likely, go to a circuit or do a canyon run and you will.
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Old 08-02-2018, 11:54 PM
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Originally Posted by mr_squiggle_1 View Post
An extra 70kg in front of the struts/front axle is very noticeable. Anyone that has an interest in cars and driving will feel the difference. You can notice the difference between driving alone and with a passenger when you drive towards the limits, another 70kg is basically another passenger full time, and one sitting in front of the axle.

I am in the same place as the OP at the moment, My R3 is going to be my street/track fun car and I would like some more power. I still haven't made a decision but I am leaning towards retaining a rotary in the car purely for the handling/balance that the car has with one. My most favourite thing about the car and my FD previous to it was the way it handled, so retaining that feel is important to me.

If we are talking drag racing or highway racing then you won't notice it most likely, go to a circuit or do a canyon run and you will.
The additional weight of an LS swap is not entirely in front of the struts or axles, and some of this weight transfer is offset by the relocation of the factory battery (15kg) to the boot . A lot of the additional weight in an LS conversion can be attributed to the T56 gearbox, which is obviously centered, and down low. The LS motor does sit much higher in the engine bay, than the Renesis though. From what I've read on this forum, a turbo converted Renesis powered RX8 weighs around the same as an LS swapped RX8.

As a generalization, those that have done an LS conversion say there is definitely a difference in the handling of the car, but it's subtle and not dramatic. But the improvement in outright horsepower and torque out of corners makes up for any downsides in handling. At a guess if you're someone who's driving your RX8 on the limits of it's handling, then an LS conversion probably isn't for you. But most would probably accommodate the difference in handling with their driving style, and simply appreciate the extra horsepower and torque that is lacking in the rotary.
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Old 08-03-2018, 12:42 AM
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Yes,
The passenger presence during taxi rides is extremely noticeable and yes I'm talking about circuit.
Maybe an option is the gm LFX v6.
I need to know too what's the limits of the osgiken superlock LSD I just installed...it will be a pita to trow it to the bin... (as for the feed 4.77).
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Old 08-04-2018, 08:22 AM
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You should immediately abandon the turbo idea, if reliability is important to you.

LFX swaps have been done successfully. If it were me, that is the route I would go, right after investigating the possibility of a K24 swap (done in Miatas frequently).
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Old 08-09-2018, 01:42 PM
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Ah ba tu es parti ici j'aurai peut être l'occasion de voir les evolutions de ta prepa alors

For me i'll say go with the REW, you won't mess up with the weight distribution and you keep rotary but the plug and play option you talked about is gone no? Alex already bought it...
But if you don't aim 500hp you can improve with a greddy turbo and few upgrades, i guess 300hp at the wheel is achievable ! And more torque too.
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