What V8 for circuit race car?

[Walt Kowalski]

My brief love affair with the ****el Rotary engine in my series 6 RX-7 race car is over.

I always hated the sound of the things but then I drove one on the track and the light weight of the engine helped car balance so much that I was hooked.

I can see why they are still track weapons after many years, even against latest model cars.

To get them really fast you need a big turbo but the heat generated causes problems in endurance races (my preferred race)

My beloved RX-7 has given me many joyful moments and although we have found the root cause of our problems (did not replace oil coolers after a crank breakage and the left over debris contaminated 2 new engines) I just want simplicity.

Sure if we were dumb enough to repeat the oil cooler issue with any engine it would also be contaminated and fail under race conditions BUT I am over rotaries just want simplicity.

It has been fantastic while it lasted but I am now looking at putting a V8 in the RX-7. Either that or sell the whole car but it is so well developed that I a lightweight V8 seems logical to what has become part of the family. He has his own personality and my grandson loves him

Therefore I want N/A and BAGS of torque for reliability and drivability. A standard engine with the breathing sorted is all I ask.

The yanks put LS1 and LS2 into RX-7 and instructions and kits available.

Toyota/Lexus Quad Cam also interests me. Apparently under 200KG and available under $1000. They tell me internals cope with big power. Is this true? Anyone know?

Does Ford have anything?

Is there something else I should consider?

I will weigh the 13B engine and turbo for comparison at some stage.

How can I find out the weight of an LS2 and Toyota Quad Cam?

I DO NOT want too much weight so anything cast iron is a no no.

Do I want Carbie or EFI? (I am useless on the tools)

Any ideas very welcome

[Falcon Coupe]

6.0 litre LS2 weighs 450lb or 205 kilo, lighter than the Ford V8's at least until Coyote is released.

The 1UZ is around 175 kilo but would lack the torque of the LS.

[KPOJ]

If that's the weight of a LS2 they would be hard to go by. The extra capacity would give you an engine that doesn't have to work as hard. Parts are available compared to the toyota engine. The toyota is an engine built to rev, resulting in faster wear rates ect ect...

[KPOJ]

http://videos.streetfire.net/video/L...WHP_123856.htm

[Zedjay]

nissan V8 with twin turbos

[RG]

There is a reason LS series engines are so popular in conversions.

[nugget378]

If budget is not an issue a complete aftermarket engine is the way to go, something like nascar spec but with more cubes and less rpm which will give a long service life between rebuilds.

A Dart or world alloy block of around 9.0 - 9.2 deck height with a big over bore and stroke giving about 430 - 440 ci, high poirt racing heads and roller cam,
I would go with a carb, but thats personal choice, it will weigh the same as an LS engine but make a fair bit more hp and torque, and is made for racing and thrives on it.

The downside is the cost, you would be looking at about 30k at least, depending on what you wanted exactly.

[KPOJ]

Originally Posted by nugget378

If budget is not an issue a complete aftermarket engine is the way to go, something like nascar spec but with more cubes and less rpm which will give a long service life between rebuilds.

A Dart or world alloy block of around 9.0 - 9.2 deck height with a big over bore and stroke giving about 430 - 440 ci, high poirt racing heads and roller cam,
I would go with a carb, but thats personal choice, it will weigh the same as an LS engine but make a fair bit more hp and torque, and is made for racing and thrives on it.

The downside is the cost, you would be looking at about 30k at least, depending on what you wanted exactly.

Low 20s for a nascar engine and revs is their friend, when not reved in the built range ie 7500-9000rpm they get harmonics causing extra bearing wear ect. Dodges are the worst with the low rpm harmonics. It will last longer revving it hard

nissan V8 with twin turbos

Thats a little complicated and might not last that long. He doesn't want turbos.

[nugget378]

Originally Posted by KPOJ

Low 20s for a nascar engine and revs is their friend, when not reved in the built range ie 7500-9000rpm they get harmonics causing extra bearing wear ect. Dodges are the worst with the low rpm harmonics. It will last longer revving it hard

You cant build half of a nascar engine for that price, If someone wants to buy a used engine of unknown history that all well and good, but I wouldnt.

They only rev them to 9500 due to the 358ci capacity limit, if they were allowed to build them bigger they wouldnt need those revs to hit the power targets and they would last alot longer, I have never heard of this harmonics thing, and am very sceptical, how can a part last longer when its working harder and under alot more stress due to more rpm, its impossible..

If you re read my post, you will see Im not talking about a nascar engine, rather, a high capacity V8 using nascar like induction, which will make big hp and t/q at alot lower rpm, and as such will be less mainenance and alot less highly strung with a broad torque band.

An engine like this will cost you around 30k, I have something similar in my XA..

[KPOJ]

I sell them (with history)

EDIT: Walt cant go over 6 litres, cams thingy.

Double EDIT: Ive been told this about engine harmonics by reputable engine builders, apparently at revs the cranks start running true ect.

[nugget378]

Originally Posted by KPOJ

Double EDIT: Ive been told this about engine harmonics by reputable engine builders, apparently at revs the cranks start running true ect.

Cool, I wont argue about it,
suffice to say I would build one that ran in the 5000-7500 range for better longevity, less stress on everything, from the bearings to the valvetrain..

[schnoods]

What sorta limit in capacity is there?

Ls1, L98, LS2 are great bang for buck options.

possibly a windsor/clevo depending on weight and revs required. A little windsor can be built to rev, but it will cost...


In a race car i dare say EFI would be ideal as long as fuel supply is up to scratch...

[4Vman]

Most stuff involving CAMS is 6.0l

[388cube_edxr8]

Mate go with a Land Rover 3.5L V8. It will rev a little harder than you want but they are all Alloy. You can pick the whole motor up with on arm if you can find a place to grab. A little supercharger and you can't lose. I was going to put one in the Gemini and race it but I need to get a job first lol.

[KPOJ]

Windsor or clevo would be to heavy, the car is already heavy enough. 6l max

[GTP owner]

Dad and i race a bmw with the lexus 1uzfe motor. In standard from it will rev to 8,000rpm and will last forever at those revs. But they seriously lack power until turboed, so steer clear of that one. Ours produced 135rwkw stock, amd currently has 250rwkw with the stadard injectors holding us at 6psi boost.

If i had my time again i would have put the chev alloy v8 in it. More expensive to buy, but cheaper to hot up, and huge power with small changes - cam/pipes/chip and 300rwkw is achievable. They also have far more adapter plates available. The lexus needs custom bits, which add up very quickly.

As for Ford product - probably the best motor currently is the xr6t motor. The v8s are heavy and not as well supported for parts. An alloy windsor style motor would be good, but very expensive

[toyocharged]

LS2 would be the go, plenty of info on the net from the states about the conversioin FD RX7s, you may need a complete drivline rethink also, not sure if the box nad diif would cope with the extra torque I would go injection rather than carby and look at dry sumping the LSx engines are prone to oil surge/starvation when the cornering gs get high. It would be a weapon but will not be as easy to drive with the extra torque, power down out of corner will be a problem.


I have a soft spot for the rotary turbos, heres a mates FD with 320kw... its good for 1.02 round wakefeild
http://www.natsoft.com.au/cgi-bin/re...2009.WAKE.S5.Y


http://www.youtube.com/watch?v=ybaypCrq8kY

A 1uz vid also with ITBs
http://www.youtube.com/watch?v=clRvHdA47rw

[Walt Kowalski]

A big thank you to everybody who has contributed. I love the AFF. You guys are great.

I will try to address each item but please forgive me if I miss a few.

Definitely do not want any forced induction even 6PSI.

I realise that handling may suffer but in the chase for reliability and simplicity BUT it is a price I might have to pay. The handling now I must say is unbelievable and I might not get that again.

Then again there is great fun to be had in having so much torque on tap from a dry sumped LS2 that a power slide or two at the end of a race is on the cards. Drivability may be a problem with power down but I will have to keep the OTC - Organic Traction Control - well maintained. RX-7 is no drifter. More a spinner.

The jury is still out on the weight differences despite lots of googling.

The weight difference of the engines may be as little as 40lbs (450 Vs 410)

By the time I exclude all the turbo stuff – intercoolers, 50MM Pro waste gate, etc this may be even less?

The V8 engine itself may have a higher centre of gravity so weigh is not the only factor that will affect handling.

Budget is “as low as possible”. This is hobby racing without sponsors so $30K engines are out of the question for a retired bloke but a built race engine around $8 is a real possibility.

It would be a dream to sell the complete single turbo conversion as one kit for somebody wanting to convert a twin turbo setup RX-7.

· 13B engine brand new to be built in next week or two

· Double Ceramic Coated T4 turbo

· Double Ceramic Coated manifolds

· Larry Perkins heat shielding

· Intercooler and piping

· PWR radiator

· Almost new 50mm Turbo Smart waste gate

· Exhaust

· Apexi FC computer

· All ducting and 15” Pod

· Anytthing else I have forgotten

The dream would be to take that money and fund most of the V8 conversion.

KPOJ has given me some excellent prices on NASCAR stuff for the driveline which is well priced, high quality, light and readily available.

If I go the Toyota route I am in the realm of expensive Motorsport upgrades again so that has been ruled out.

LS2 dry sumped it is.

Current fuel supply will cope. It has two Holley Blue fuel pumps feeding from the fuel cell to the swirl pot and a Bosch 044 from there.

Unless you guys can tell me otherwise.

Thanks again for all the input. Keep it coming.

[ebxr8240]

1JZ or 2Jz ?? Yes back to turbo .. But they are very durable..
How about the 4.6 Cobra engine??
Cheap in U.S but a little expensive here..
Chevy seem to have weight to power advantage and aftermarket
performance parts..
I guess your after 400 / 500 usable h.p ??
In a light good handling body it would be very quick..

[Bad Bird]

I dare say the weight difference between the LSx and a 13B with all its turbo accessories will be a wash. You could set the V8 fairly well back into the engine bay, as they are fairly compact. I don't think handling will suffer as a result of the swap.

The 2JZ is a good motor, but I think it would be very long, tall and heavy - not particularly suited to the RX-7.

[XR6_661]

Wanna sell the 13B mate.....

[toyocharged]

Walt as profi has found out the L98 is the gun engine compared to a LS2, much better head design

[mik]

a friend who is pretty up on engineering reckons early LS blocks suffered from flex, he was in the same boat as yourself, having a severly modded supra , after getting it to the max power levels wanted a cheap reliable transplant for more power, he went for a late model brand new compact LS motor complete engine manifolds coil packs for 5 grand odd if my memory serves me, it might be worth looking into.

[Walt Kowalski]

Originally Posted by toyocharged

I have a soft spot for the rotary turbos, heres a mates FD with 320kw... its good for 1.02 round wakefeild
http://www.natsoft.com.au/cgi-bin/re...2009.WAKE.S5.Y


http://www.youtube.com/watch?v=ybaypCrq8kY

A 1uz vid also with ITBs
http://www.youtube.com/watch?v=clRvHdA47rw

[font=Times New Roman', 'serif]I used to have a soft spot for them too. But 4 engines in 15 months (5th 13B about to be built) and I am over them. They might be fine for a really fast lap in a Super Sprints and Sprint races but try using them in endurance racing. [/font]

[font=Times New Roman', 'serif]The problems from heat sink are too much for me. Things just melt despite the best efforts, materials, shielding, installations etc.[/font]

[font=Times New Roman', 'serif]Brad's l.02 at WP has become legendary. Probably the fastest RX-7 ever at WP? Somebody correct me please. [/font]

[font=Times New Roman', 'serif]My best is a 1.04.32 (lap 128) in enduro tune and setup with 220KW ATW. I wanted to go to that RENEW day but engine No 4 was not quite ready. Getting a pattern here anybody? I am missing events because the thing is in the workshop.[/font]

[font=Times New Roman', 'serif]Brad can really drive (His Dad is pretty handy too) and it is a REALLY powerful car. I am told 370KW bridge ported turbo. Is that correct? [/font]

[font=Times New Roman', 'serif]It is beautiful too. I was actually at the importers the day they unloaded it from the docks. 11,000klms from memory. I told a guy about it and next thing it was in his workshop getting fitted out for Brad.[/font]

[font=Times New Roman', 'serif]I was also in that same workshop (that pattern again) on the Tuesday after Brad’s legend 1.02 lap when a guy with a 2008 Porsche Carrera S came in and said "I want an RX-7 for the track”. Apparently all the Porsche guys were talking about Brad's lap. I saw the guys beautiful Porsche out the front but he definitely wants an RX-7. I think he's getting a Pearl White one based on a late model Series 8 RZ.[/font]

[font=Times New Roman', 'serif]Now what’s this about L98? I have never heard of it so THANK YOU for the tip. [/font]

[font=Times New Roman', 'serif]Anybody got any more clues about L98?[/font]

[KPOJ]

www.holmart.com.au

They sell l98 crate motors for around $4500.

[Walt Kowalski]

6.0LT L76 brand new $5200

HSV LS2 Brand new $5,490


Much cheaper than a rebuilt 13B!!!

Is that what I want?

I dead set am confused despite a trip to wikipedia

PS What an amazing website. Does Ford have something like this with everything from basball caps to engines?

[KPOJ]

L98 is the one to go for, they have the good heads.

[ebxr8240]

A 20b ??

[KPOJ]

http://www.drysump.com/corvpan1.htm

[KPOJ]

Originally Posted by ebxr8240

A 20b ??

You are mad...