Sorry for the long post - The purpose of this thread is to share my engine/transmission selection research so far for anyone else still in the design phase, and to pose a few questions about transmission adaptation, while hopefully gathering a few more engine selection suggestions. For reference, I'm in the design phase of a mid-engined two-seater similar in spirit to Steve Graber's La Bala - http://www.grabercars.com/
. The body style will be close in stature to the GreenGT
Concept Le Mans car, though custom designed from the ground up for two passengers, rather like the Ultima GTR:The GreenGT Le Mans Concept Racer & The Ultima GTR, respectively.
After debating if I should post this in the Non-Traditional section I've decided it's more of a engine/transmission subject than anything, and that the info shared could be used equally well by those building traditionally or otherwise.
After about 6 months so far of serious engine research I've landed a few select engine choices but need a little help with transmission options. The target weight for the car is 1600 lbs given the high output engine type and full two-seater bodywork and interior, and the target power-to-weight ratio is around 400 hp/ton [about the same as a Porsche GT3 RS] which yields a target power output for the engine of about 300HP.
After much debate, the 205HP supercharged LSJ and the 260HP turbocharged LNF have been my two decided engine choices for they're wide availability, high power output, light weight and reasonably low price. In the four cylinder range they seem to take the cake for stock horsepower and torque levels and reliability. They're also usually found mated to the FWD transmissions from the Cobalt SS which is a requirement for a middy that unfortunately excludes many otherwise very capable engine options without having to adapt any particular FWD bellhousings to fit, saving money.
But after further research I've decided not
to go with a 4CL, but rather a 6CL for the benefit of around 250HP stock with natural aspiration. I do not plan to avoid forced induction, rather only to have a base platform that performs well without it & from there boosting it only slightly to offer about a 30% power increase, mostly to avoid turbo lag [though I know the Ecotec handles this issue well], and to offer a little more torque. Also, I just love the exhaust note from a well-tuned, high-output V6. Also, as the all-aluminum Ecotec 4CL weighs 307 lbs [source
], several all-aluminum V6 options actually weigh less
in N/A form [The 260HP Honda 3.2L J32A2 from the Acura TL for example weighs in @ 250 lbs], while offering more horsepower & torque.
Even more provocative is the price. As the import tuner craze hit the States, prices on these high-output 4-Bangers have gone up drastically, to the effect that it is effectively cheaper in the end to purchase a +350HP LS1 V8 than some of these 200HP 4CL Honda engines - Sh%# just doesn't make sense. More to the point I've managed to find some very capable +250HP, 300LB V6 engines for less than $600, whereas the 205HP Ecotec LSJ goes for around $2200, and the 260HP Ecotec LNF for around $2600.
As for V6 options the best I've found so far are as follows:
There are several other FWD-Compatible import & domestic options available as well, such as the Chrysler SOHC 3.5L V6 which produces 214HP & would be especially good if you're lucky enough to find the lightweight 250HP all-Aluminum EGG version from 1999-2005, otherwise it'd be much heavier than the other options - I haven't found many cheaper than $1200 however, if at all. I'm also not fully aware of any FWD manual transmission options, though I believe there are a few. Another option is the 225HP 3.8L Buick L67 V6, though this engine is supercharged so would generate more heat, weigh more and take up more space for less power, and features a cast iron block which very well may be bulletproof but coupled with the supercharger & accessories would weigh much more than any other option. I'm not sure on the price or availability of one either, but they're used very well in the Lotus-Styled Brunton Automotive Stalker V6
, which held the Unlimited Time Trial Homestead-Miami Speedway Lap Record for over a year & was only just very recently broken by a 2006 Radical SR3:The L67-Powered Brunton Automotive Stalker V6
First on the list is the 3.5L Nissan VG35DE V6 - produced in many different forms from 2001-2008, this engine is capable of 240-300HP in stock N/A form. This engine can be most readily sourced from a 2002-2008 Nissan Maxima/Altima in 260HP form for around $700 with less than 30K miles. Weighing in at 313 lbs, it is the heaviest of the three I've listed above, and also the most expensive, but only slightly. A compatible manual FWD 6-speed transmission can be sourced for a little less than $1000. Buying the entire car as a donor would also be a great option for this engine + transmission, though finding a manual version may prove quite difficult. A Quaife ATB differential is also an available transmission upgrade for $1000 which is a huge plus for future upgrades.A 3.5L Nissan VQ35DE V6 Engine
Second on the list is the 3.0L Ford Duratec 30 V6 - Produced in several forms from 1996-Present, this engine produces 203-221HP in stock N/A form. This engine can be most readily sourced from a 2006-2009 Ford Fusion in 221HP form for around $450 with less than 30K miles. Weighing in at 225 lbs, it is the lightest of the three I've listed above, and also the cheapest. A compatible manual FWD 5-Speed MTX75 transmission can be sourced from a wide variety of vehicles for less than $300 in really good shape. A 6-Speed manual Getrag transmission can also be mated to this engine from a Ford Focus SVT [I believe it's the Focus, better double check], though these have proven less reliable than a good-quality MTX75. Buying the entire car as a donor would be preferable as always, though the MTX75 transmission may be more easily sourced separately. A Quaife ATB differential is also an available transmission upgrade for $500-$1000 which is a huge plus as always. The most notable feature of this engine may be that it is featured in the Noble M12, a very well-designed supercar developed by Lee Noble himself, though in the M12 the engine is far from stock. The Noble M12 uses both the 5-speed MTX75 and the 6-speed Focus SVT transmissions as available options, apparently in stock form as the 6-speeds have been known to disintegrate on the track under stress. I assume the boost in power levels of the engine is assumed by Noble to be canceled out by the extreme weight reduction between the M12 and the cars originally designed to use these transmissions to excuse the lack of upgrades to prevent transmission failure. The MTX75 has very good aftermarket support for upgrading for heavy track use, for example by HMS Inc
led by Terry Haines. Haines will performs various levels of upgrades to the MTX75, with a full upgrade suite running at about $1500 to make it pretty much indestructible. Overall, the 3.0L Duratec V6 is very good option indeed, though apparently not the most original
- But hey, great minds think alike!A 3.0L Ford Duratec 30 V6 Engine
Last on the list is the 3.2L Honda J32 V6 - Produced in several forms from 1999-2008, this engine is capable of 225-260HP in stock N/A form. This engine can be most readily sourced from a 2004-2008 Acura TL in 260HP form for around $600 with less than 30K miles [though if you can find it & you have a little extra cash try for a 3.5L J35
from a 2007-2008 Acura TL Type S, as they produce 290HP in stock N/A form
]. Weighing in at 230-250 lbs, it is the second lightest of the three I've listed above, and also the second cheapest. Finding a manual transmission to fit would be the most challenging aspect of this engine choice, as the only manual FWD transmissions that bolt directly to it are the 6-speed transmissions from either the 2003 Acura CL Type S [extremely rare] or the 2002-2003 Acura TL Type S [moderately rare] or the 2004-2007 Acura TL [base model, as no Type S was produced for these years - these are also the only ones to feature an LSD if I remember correctly]. After running a few searches for one of these the cheapest I've found are for ~$1600 from various recyclers. I've also not found any aftermarket differentials for this transmission at all, which is a huge dissuasion from this engine choice. Buying the entire car as a donor would be preferable as always, but very expensive for this engine choice considering the late year model purchase necessary to source the right transmission. The cheapest acceptable 2004 6-Speed Acura TL I've managed to find as a donor is about $3500, wrecked. I hate to say it because to be honest this is my favorite engine on the list for originality, but because of the transmission complications this is the least viable [most expensive] option as a complete package.A 3.2L Honda J32 V6 Engine
Also notable with the Honda J32 option is the frequent failure of the compatible 6-speed manual gearbox synchronizers over normal consumer wear causing the shifter to slip into neutral unexpectedly; coupled with frequent track use this would prove quite a problem. I'm not aware of any aftermarket transmission upgrades for this transmission either, which coupled with the expense and rarity of a compatible manual transmission effectively narrows down my choice to either the Nissan VQ35DE or the Ford Duratec V6. This to me is dissatisfying though considering the J32 is my favorite engine of the three; using the Duratec V6 to me would feel like the obvious choice
, as it's used in the Noble M12 - Thus I like the apparent originality
of using the Honda J32. I also like the little extra stock horsepower and torque over the Duratec V6.
For this reason I'd like to explore transmission adapter options, but this is a topic that isn't as well covered in the forums & thus the purpose of this thread. Who here has adapted a transmission to fit an engine & generally how expensive is the process? I like the idea of transmission adaptation also because it would allow me to choose virtually any
transmission I wanted to fit the car. This could potentially significantly reduce the cost of finding any one particular transmission & would allow me to choose a transmission better suited for high power output & torque loads. This would also greatly expand upon my potential engine choices, not only opening up the option to use the Honda J32 but also a vast selection of other unmentioned engines previously ignored for the lack of support for FWD transmission options. This would also allow me the option for a Quaife LSD or ATB differential no matter which engine I choose.
I realize having a transmission adapter plate machined can be quite costly, but I may be able to at least mostly make up for the extra cost by choosing a cheaper transmission to suit my needs, possibly equaling the original cost of mating any one particular engine to it's counterpart transmission. Now that I've decided against the $2600 Ecotec 4CL I've been spoiled by the idea of a $600 V6 and would like to keep the total cost of transmission + engine to <$2000. If machining an adapter plate or buying a custom bellhousing doesn't break this limit I'd sure like to know about it.
Again, sorry for the long post & random questions inserted throughout; hopefully this info is helpful to some.