Why cant i use my boot space to mount a massive engine?

[MurcielagoR2]

Hey guys, so ive got this 3year plan for my baby (picd in my avatar) and the last stage of it will be the engine conversion.

Ive seen a lot posted about the V6 conversions that have been done and up until now ive been all keen for a 3MZ-FE conversion. Im so serious about it i almost bought an engine from a friend but it turned out hes gonna keep it

Ive been standing behind my car, staring at the engine bay (tiny as it is) and ive been wondering this. Why cant i just cut out the firewall to the boot, and longitudinally mount a LS1 or some other monster engine?

Basically i need some all knowing MR2 specialist browsing these threads to tell me YES! It can be done! or NO! It cant be done because blah blah.... Id really appreciate the feedback. Thanks guys.

[SW21T]

If you cut the trunk out, I'm sure you can get something big in there.. I've seen an MKI with a 350 in it and they cut the trunk off and molde the engine lid to the trunk lid to make one big lid..

[MurcielagoR2]

Ive actually just been on wikipedia and the mr2 used by TRD for racing had a 3UZ-FE in it. Anybody know why a 1UZ-FE wouldnt work? Can anybody tell me the size/dimensions of the 1MZ-FE or 3MZ. I cant find any dimensions anywhere! I want to compare them to the 1UZ-FE and thatl give me a fair idea of my limitations.

[fidget]

Of course it's possible. It's just a matter of how much money your willing to drop into it. Also with a "massive engine" comes massive weight gains, which would throw the entire car out of what I consider a very delicate balance. Hopefully someone with a chubby v6 swap can chime in with how it handles with the new power and equally new weight.

[328FTW]

You could chop out the boot but you would be shifting the weight further back which would make the car handle funny. It could be made to handle alright again but the MR layout is better and is easier to control.

A 1UZ-FE would require some serious fab work to work right but it could be done, probably a tubed rear end which would be cool.

[Breed-X]

if you look at the JGTC and sard versions then the boot is allready cut out to give more room, i cant't see why you cant cut it out, the subframe will easyly hold the engine, but how about transmission?
Sard is 33cm longer then a normal MK2 wich is not much.

Sard Racing MC8R

[328FTW]

That is a lot of engine to cram in there, plus the GT1 has a lengthened wheelbase so that would help with fitting it in and calming down the the resultant twitchy handling.

[MurcielagoR2]

Is it a major issue to lengthen the wheelbase if i do put a larger engine in and thus transfer more weight to the rear? I would expect that to solve most of the "balance" issues and then it would be more about adjusting the suspension components to balance the way the car feels/controls? Cost isnt a huge issue here. Obviously dont want to spend 100K but im happy spending plenty to get this done and done right.

[MR JAS]

Originally Posted by MurcielagoR2

Is it a major issue to lengthen the wheelbase if i do put a larger engine in and thus transfer more weight to the rear? I would expect that to solve most of the "balance" issues and then it would be more about adjusting the suspension components to balance the way the car feels/controls? Cost isnt a huge issue here. Obviously dont want to spend 100K but im happy spending plenty to get this done and done right.

your main problem wont be just to much weight at the back but to much weight behind the rear axel many of these engine combinations would effectively make it rear engine so you would have to move the axels back which means refabing the entire suspension and bidy otherwise you will end up with something like a porsche 911 30 years and hundreds of millions of dollars of development to make it handle like it would if they just made it mid engined

[MurcielagoR2]

I think im starting to get a proper idea of why this hasnt been done. Id really love that longitudinal mounted v8 look in the back but im starting to think im just gonna have to paint the engine cover instead of have it tinted.

[Oteck]

reason it hasn't been done is there's no room between the axle and the front firewall, you can cut the trunk all you want but it still won't leave you room for anything. notice the Sard is much longer around the vent area

[ozone]

I'm not a Mk2 expert by any means, but it seems to me that a lot of these answers are kind of negative.

1. The MR2 is a mid engined car. While the engine is not at the exact center of gravity of the car, it is much closer than non-mid engined cars. This means that the balance is much less of a problem than it would be if the car were front engined. Plus there is nothing that says if you are willing to do the work that you couldn't take steps to remove some of that weight, bringing it back into "balance." For instance, do you want AC? While I agree that balance is important, do you really feel that big of a difference when you carry a passenger. That's say 180 lbs extra weight right there (admittedly more toward the middle of the car) but that doesn't come with any gain in HP/torque at all. If you think that having a passenger in your car is the worst thing that can happen to the balance, then you definitely don't want to do this. Personally, I don't notice that big of a difference and even if, I'd carry around a passenger to double my horspower.

2. Read this awesome document, where a guy put a 3vzfe into a MK1. http://forums.twobrutal.com/files/v6mr2.pdf
He did so by cutting the trunk, just as you have suggested. He was even able to put the trunk back in, with only about an inch or so loss of space. It's a matter of checking the weight and size of the engine you want to install. Plus, if you can cut the trunk, why can't you cut the passenger compartment. You should probably do this anyway, just to access the front spark plugs.

3. I have rough (very rough) dimensions of a 1mzfe/3mzfe engine on my website at New Page 1. Go into the Corolla section and then into the V6 section.

4. It would be wiser to choose a V8 or V6 engine that is normally transversely mounted. While I'm sure it is possible, even likely that some of these engines are designed with the center of gravity behind the axle line, I can tell you for a fact that the 1mzfe/3mzfe engine you mentioned is not one of them. I do not believe that the center of gravity would shift enough for you to notice or be concerned with.

5. I think the selection of a V6 vs. a V8 would probably be a better choice in this case, but it's completely up to you. On Spyderchat.com: The Online Community for Toyota MR2 Spyder Enthusiasts! there is a guy with a mk3 MR2 featuring a cadillac northstar engine. That's a pretty small engine bay too.

6. I think where you would have most of your problems would be in the details. Are you willing to drive an automatic? That would be much easier, I think because the 3mzfe for instance was never available with a manual transmission. While the E153 will fit, getting it to work properly may be a problem, because the stock computer wants to retard the timing on upshifts to mitigate shift shock. I'm not sure how you would keep this from happening if you put a manual transmission on it. The 3mzfe also has throttle by wire, which I think would be easier to install, but many people don't like it. Can you handle this? What drive shafts would you use?

So the main thing, I think is, you have to do a lot of research before you even consider buying anything. I have a tendency to try to find the engine schematic for the prospective donor and go through the entire thing to envision how I might do this. For instance, if you want to use the stock ECU, many cars come with chips embedded in the car key. The engine won't run if the ECU doesn't see this chip and read it's code. So if you want to use the stock ECU for the engine you choose, make sure you get the keys and the immobilizer key reader with the engine, when you buy it. What parts would you use from your car and what parts would you use from the donor? It's a lot of work, but it can be done.

Good luck and keep dreaming!

[David]

Just wanted to post a pic of an MR2 I've seen with the firewall cut out.

[MurcielagoR2]

So i was doing a little more surfing, coz you find alot out that way, and i came across this picture. These guys have moved the turbo MR2 engine back 10inches!! It looks like they may have also fabbed new pillars and moved the wheels back as well? Certainly by doing this you make it near impossible to make it look like it did orginally, but im not going to have that problem when im done anyway.

Ive heard you can put an Audi 5000 gbox on the 1UZ-FE and mount it longitudinally. If i stretched the back end out that would solve balance issues and provide room for a longitudinal mount engine? Just putting it out there. This forum is really helpful

[Jason.MZW20]

A longer wheelbase will make the car more stable at high speed, but you'll also lose a lot of the car's go-kart feel (more so over the MKI). It'll become more of a GT car. If you notice, the Ferrari F430 has a wheelbase that is over 100 inches. That goes for many supercars. They make up the for the reduction in low/high-speed direction change with innovative suspension design/geometry and aerodynamics.

The MR2's wheelbase is extremely short at 94.5 inches. The Ferrari F430 is nearly 8 inches longer at 102.4 inches. The Audi R8 is nearly 10 inches longer at 104.3. The only supercar with a short wheelbase is the 911 Turbo at 92.5, 2 inches shorter than the MKII MR2. This is why the 911 has great turn-in and direction change, but is also tricky to drive at higher speeds.

You'd have to completely redesign the rear suspension to lengthen the wheelbase. You might as well use a double wishbone or multi-link rear for greater adjustability, if you're serious about such a large project.

Also keep the brake caliper in front of the rear axle line. Toyota did this to focus weight toward the center of the car. You'll notice the front caliper is mounted on the rear of the rotor. Again, to focus weight toward the center of gravity.

[mr2greasemonkey]

mmm.......sssssaaaaarrrrrrdddddd........

[como]

The Northstar V8 Toyota MR2
I've been following this guys worklog for about a year, last I read he was having serious trouble with the custom rear suspension, but its a fun read (with lots of pics)

[streetrack 3vz ht]

2gr and turbo it then be done with it

[1stgen]

This reminds me of all the Northstar Fieros that used to be at the SCCA tracks.

[muffinman]

Originally Posted by como

The Northstar V8 Toyota MR2
I've been following this guys worklog for about a year, last I read he was having serious trouble with the custom rear suspension, but its a fun read (with lots of pics)

That hasn't been updated since jan. 07.