I am doing an L33 swap into a Mazda Miata 1990 NA. I choose the L33 for a few reason:
315 hp stock, not as expensive as the LS1 and you can still get 400hp + out of them with a mild tune and cam upgrade.
I have purchased the Boss Frog K-Member and Transmounting kit.
Using a L33 engine is from a 2005 Siverado Extended Cab with 29k miles, T56 Trans, Ford 8.8 IRS Z06 Cam upgrade as a starting point.
Here is the donor:
I have the k-member installed and the engine test fitted to the new subframe.
I am using 1.75" setback adapter plates instead of the standard ones offered by Boss Frog to get the engine as far back into the tunnel as possible. Require some tunnel surgey but it is pretty straight forward.
These are the plates I am referring to. I got these at http://carshopinc.com, but Boss Frog will be offering these as well in the future.
If 1.75" setback is too much for you your can get the 1" setback plates.
With the 1.75" setback plates this is how close the head/block gets back to the firewall.
The Boss Frog kit allows me to use a stock LS1 oil pan without any mods. But with the setback adapter plates I am using I can use the C5 oil pan as well. I like that since the C5 pan has better oil control for road course use as well as no chance of dinging up the pan on road hazard.
No worries with ground road clearance here:
Still has good access to the oil drain plug.
Pleanty of clearance on the steering rack (yeah, I know, I've not cleaned it yet):
A quick word about the C5 pan. The passenger side of the pan does contact the k-member. You can grind away a little of the pan right at the edge to remove enough of it so it does not touch. This would probably be enough if you are simply going to use this as a street car.
But I am a little concerned about heavy track use. The k-member might stress under high load turns which could put pressure on the pan enoungh so to crack it. I don't know, but I see it as a possibility.
I would rather notch the k-member at this section as it is less than a two inch section then weld in a patch and then weld on a piece of angle iron to provide added strength in case the notching weakened the unit. That's what I plan to do.
Another draw back to some, you do have to do modifications to the firewall. Not extreme, maybe a little more than the V8Roadsters kit.
Other than that I see no problems with using the 1.75" set back plates and the C5 pan. Accomplishes a lot.
1) Better weight distirbution as the engine is furthest back from any of the kits offered.
2) Improves ground clearance with no risk of pan contacting the road.
3) Improved oil pan baffling provided by the C5 pan for road course.
4) Puts shifter further back in the whole closer to stock location than other kits.
5) Requires no modification to pan or need to purchase another pan.
__________________ FOR SALE: 1991 Mazda Miata with 328whp/355wtq LS1/T56, Ford 8.8 3.55 diff, Ohlins coilovers, Hard Dog 6-point roll bar. Drivetrain mounted with racingconcepts.net kit.
Build-up website: www.swaptastic.net
Other car: 2009 Pontiac G8 GXP 6spd
Pretty much decided on the way to go with the Ford 8.8 Differential.
Going to make a hanger like the one pictured here:
Except instead of the front mounting shown in the left hand picture I want to try to use the Miata Torque arm like this guy did at LS1miata.net. Should help with the wheel hop issues. Instead of mounting to the trans tail I plan to weld a mounting point to the cross member.
Any thoughts.. pros .. cons...
The Miata PPF (torque arm) is known to twist severely, even under slightly boosted 1.8 SC applications & will do very little, if anything, to resist the torque of the 5.3. Best solution is to use the Cobra 8.8 diff housing cover & attach it to the frame (your reference pic on the right). Although, I'd go w/ a more stout attatchment than the tab shown in the example.
__________________ LSX powered MUNSTER.....Mod's list? 5 lbs per HP with a sh!t load of low end torque...Friend to all car people...Thanks LS1Tech
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Just picked up the trans from being rebuilt. Actually I had two T56's each with its own issues. One needed a cluster gear, input shaft and new synchros, the other in need a shift rod and 5th gear. But together they make a fully funtional T56 which I will get installed this week for test fitting.
Now I need to say something about my transmission guy. He's a very good man that owns the AAMCO shop on N. Military Highway in Norfolk, VA. I would mention his name but I hate to mention someone's name on the internet without their consent. He's a racer and I felt bad that he would not even take the $100 I held out for him after he said I owed him nothing for the work. He took my two T56's and built me a new one and charged me nothing just "did it to help the racing community". His words.
So if you are in the Hampton Roads area of South East Virginia and have a transmission issue I highly recommend his shop.
Last edited by modracer33; 10-13-2009 at 11:31 AM..
Good work so far. So what are you going to do about axles?
I have a local shop that is going shorten and rebalance my drive shaft and then my set of stock T-Bird axles, shorten 2" on each axle and rebroach my hubs. This will get me on the road.
But long term (for racing) I will have a set of 400hp or 600hp made by the DriveShaftShop. They are out of Salisbury, NC. Do a great job for half the cost of some others.
Been sorting out several issues of over the past month.
I have pulled the rear end subframe and fab'ed the mounting brackets for the Ford 8.8 IRS.
Here is the drawing for the rear diff hanger:
The design for the diff snout mount:
The snount mounted:
The snount mounted with poly bushing (upsidedown):
The rear of the diff mounted with poly bushing (upsidedown)
It is mounted to allow use of the same length axles on both sides.
Also, found that Factory Five Racing (FFR) offers an 18" axle shaft which appears to be the right lenght. I have ordered and received two completed CV axles and will test fit those hopefully later this week. My diff is at a shop having the a 3.73 ring and pinion installed.
I plan to use the Miata Upright, but have purchased Ford Tbird hubs which I am having machined down .05 and redrilled to 5x4.5 bolt pattern to be pressed into the miata bearing. This will allow me to use the new FFR axles in the Miata rear suspension. Available options would be to re-broach the Miata Hub or use a TBird Upright and build a new lower control arm.
Installed the LS7 Z06 Cam into the 5.3L L33. The LS7 uses 1.8:1 ratio rockers and the L33 only 1.7:1. So my cam will have only a 562ish lift. Still need to install my new valve springs and will need to check push rod lenght and the base onthe LS& cam was .05 smaller than the L33's. Yes I have the LS2 Timing Cover and the Half Moon cam gear.
Have welded up all the tunnel mod seams and make modificatioins to the dash as needed for the MiataCage to be installed with the dash bar behind the dash.
Currently working on getting the full cage from MiataCage.com installed. Welding the landing purches this week and hope to start welding in the tubes over the weekend and next week.
Last edited by modracer33; 11-17-2009 at 12:21 PM..
Reason: typo
Shoud have mentioned I did go a head and modify the Boss Frog subframe so the C5 pan would not rub the control arm mounting rails.
I had ground about 1/16" off the pan so it no longer touched the rail. I was still concerned the pan would rub and then with on track stresses actually crack due to severe contract with the rail.
Here is a picture of the pocket I mod'ed into the rail.
My original plan (see drawing) was to notch the rail and support the notch with an angle iron down the outside.
I changed that and instead used the angle iron to build a pocket in the rail which is a stronger eliment.
Then I further strenthened the rail with a 5/16 falt bar weld to the outside. Should be stronger than the original design now.
Good to hear that the Batwing will work with minor modifications. Do you whether or not it will work with the V8R kit? I still haven't decided which subframe to go with, but that may influence my decision.
Michael
__________________ Aurora Motorsports|Fabricating High Performance
95' Miata Turbo|Soon to be LS6
Good to hear that the Batwing will work with minor modifications. Do you whether or not it will work with the V8R kit? I still haven't decided which subframe to go with, but that may influence my decision.
Michael
I have never seen one of the V8ster's in person. But from the pics at Nathan's site, the area on the passenger side rail just rearward of the front lower control mount, appears to have a round bar from the rack mount welded there. If that is the case then the answer is NO, the wing would hit that bar.
BF uses a plate gusset welded to the bottom at that location for support does not interfer with the C5 pan.
Also because the BF kit puts the rack foward of the spindles tie rod mounts to the same degree and the oem and V8sters have them behind, you do not have to mod the pan underside. In otherswords the rack is extended far enoung to have the clearance you otherwise have to make. This clearanceing of the pan would be required for the F-body or batwing pan, unless you purchase the FM pan.
On the negative side, moving the rack forward, accroding to BF caused no issues. I am taking a wait and see on that. I imagine some bump steer adjustment will be necessary.
JUST REMEMBER, in order to use the C5 pan you will have to use the 1.75" or 1" setback back from carshopinc.com. Otherwise the C5 cannot be used without further mods to the BF subframe.
L33 Conversion in a '90 Miata 
