LS powered Miata swap- Build Thread
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From: Hattiesburg, MS
Update with pictures tomorrow.
The engine arrived tonight!!! LS1 from a 2004 Corvette with 22k miles.
I started stitch welding the front of the car a bit today. I don't know how much it will help, but figured it couldn't hurt. Should be getting all my parts from Boss Frog sometime this week too. That means next weekend i can start fitting the engine in the car and making final adjustments in the engine bay. Then make it all pretty and paint it!!!
The engine arrived tonight!!! LS1 from a 2004 Corvette with 22k miles.
I started stitch welding the front of the car a bit today. I don't know how much it will help, but figured it couldn't hurt. Should be getting all my parts from Boss Frog sometime this week too. That means next weekend i can start fitting the engine in the car and making final adjustments in the engine bay. Then make it all pretty and paint it!!!
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Engine, subframe, etc. arrives!!! So engine arrived last night, and i woke up this morning to find all my Boss Frog stuff here. They did an awesome job packaging everything up. One of the frame rails had a dented corner, but i'm sure a gentle tap from a hammer will fix that. Here are the photos:
Subframe
Dented Corner... Fed Ex
Barely had a chance to unwrap everything before running off to work, and still got there late. I will try to take some better photos later tonight maybe.
Subframe
Dented Corner... Fed Ex
Barely had a chance to unwrap everything before running off to work, and still got there late. I will try to take some better photos later tonight maybe.
On The Tree
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From: San Anselmo, CA
Ok, dark_demenshun, the race is on!!
I decided on Sunday to officially begin my miata LS1 conversion. I'm engine/tranny shopping and already have a line on the donor car. I'm ordering the V8 Roadsters swap kits today. I've spotted you about a month, it seems, so we'll have to push to catch up...
Since I love to make things more difficult for myself, I'm considering using a five speed T5 transmission instead of the T56. It's about 50lbs lighter and I can't imagine ever needing 6th gear (I'm building a car for the track - it'll never see the highway). Thoughts??
Cheers,
Dean
I decided on Sunday to officially begin my miata LS1 conversion. I'm engine/tranny shopping and already have a line on the donor car. I'm ordering the V8 Roadsters swap kits today. I've spotted you about a month, it seems, so we'll have to push to catch up...
Since I love to make things more difficult for myself, I'm considering using a five speed T5 transmission instead of the T56. It's about 50lbs lighter and I can't imagine ever needing 6th gear (I'm building a car for the track - it'll never see the highway). Thoughts??
Cheers,
Dean
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From: Hattiesburg, MS
haha, you will probably get yours done faster. I just finished using up the funds from selling my Integra, so now it is all going to be saving up. I would personally still go with the T56 since there are so many companies out there that support it. In this car i don't think 50lbs is really going to make a ton of difference. I'm more concerned about what rear end setup i am going with, and if i can get the power to the ground. Then i will just worry about making more power, not the weight.
I'd like to comment about this. Have read all of the opinion over on the Miata site where guys whom have never used a T-56 are stating how much more driver friendly a T5 or a Muncie, in a Miata, is. Further, how 6th will never be used. Have seen that some of the comments are coming from those w/ 3.23:1 rear end gear ratio's, as well. A 3.23 would definately like the Muncie gearing over the T56. The point is to know ahead of time where you want to be. A T5 without strength mods is not strong enough for LSX powered reliability. If it's a 302 based project, then OK.
In my 5+ years of driving & owning (after re-building) a true 400/400+ Miata, can say that the T56 is a great choice. 50# is like a gnat on the *** of an Elephant in an LSX powered roadster. If you can, I'd recommend the Viper gearing over the stock T-56 gearing. However, if the stocker is all that is available, then the difference between Viper & stock can be partially balanced w/ rear end gearing. 3.55:1 w/ Viper gearing & 3.73 or even a 3.90w/stock T56 gearing. Any shorter rear end gear & traction would be more of an issue than it already will be.
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From: Hattiesburg, MS
Some very good insight there. Thank you!
Dan, i will have to let you know later tonight when i am able to take a closer look. It seemed pretty sturdy to me, and maybe weighed around 5lbs. I will get you some hard facts tonight though.
EDIT:Dan, the crossmember itself weighs right over 9lbs. I have some photos that i will load up tomorrow when i get to work. So far as quality goes (this is for the subframe too), i would say it is average to good. There are some edges that are not smooth at all, some flaws in the paint (which appears to be flatblack spraypaint), etc. Nothing major at all though, just finishing details. The overall construction seems very sturdy, and the welds look great. I honestly couldn't imagine a tubular subframe coming close to the strength of this subframe design, and the crossmember is about as sturdy as i could ask for too. I would have to say they didn't go for weight savings, but rather reinforced construction, and honestly that is exactly what i was wanting. I can always add more power to compensate for the added weight (which is really minimal). Overall strength is what matters most to me, and they did an excellent job in my opinion.
Dan, i will have to let you know later tonight when i am able to take a closer look. It seemed pretty sturdy to me, and maybe weighed around 5lbs. I will get you some hard facts tonight though.
EDIT:Dan, the crossmember itself weighs right over 9lbs. I have some photos that i will load up tomorrow when i get to work. So far as quality goes (this is for the subframe too), i would say it is average to good. There are some edges that are not smooth at all, some flaws in the paint (which appears to be flatblack spraypaint), etc. Nothing major at all though, just finishing details. The overall construction seems very sturdy, and the welds look great. I honestly couldn't imagine a tubular subframe coming close to the strength of this subframe design, and the crossmember is about as sturdy as i could ask for too. I would have to say they didn't go for weight savings, but rather reinforced construction, and honestly that is exactly what i was wanting. I can always add more power to compensate for the added weight (which is really minimal). Overall strength is what matters most to me, and they did an excellent job in my opinion.
Last edited by dark_dementshun; Jan 14, 2009 at 12:20 AM.
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From: Hattiesburg, MS
Well, i'm not sure where you got $1500 from. I just spent $1700 with Boss Frog (including shipping), and got the subframe with motor mounts and longer steering shaft, transmission crossmember with frame rails, and clutch master cylinder with line.
V8Roadsters kit is $2350 and includes a tubular subframe (which i was concerned about for long term strength) with motor mounts, transmission crossmember with frame rails, and rear diff mounting setup that i was skeptical about for strength reasons too. (To defend the V8Roadsters kit, i will say that it has been tested and used by several people. I don't know of anyone that has had anything on it fail. I just chose the company that designed the subframe closest to how i would have done it.)
Racing Concepts (yes the site is still up even after all the complaints) kit is $2000. The kit includes tubular subframe with transmission mounting kit, engine mounts, exhaust manifolds, and new steering shaft.
They all seem to be right around the same price wise for what you get. It seems like V8Roadsters kit was designed more for weight savings (which does appeal to a lot of people) while the Boss Frog one seems to be more about strength. I don't know about you, but i want it strong, to last long, so i can get my friction on!
Here are some better photos that i took last night.
Transmission Crossmember:
Subframe (sorry i didn't have any tools inside to take the shipping "feet" off):
Flipped over:
Closeup of some welds:
One side view:
The other side:
And a view from straight overhead:
I hope that helps some people out. I know there are not a lot of photos out there of the Boss Frog kit.
V8Roadsters kit is $2350 and includes a tubular subframe (which i was concerned about for long term strength) with motor mounts, transmission crossmember with frame rails, and rear diff mounting setup that i was skeptical about for strength reasons too. (To defend the V8Roadsters kit, i will say that it has been tested and used by several people. I don't know of anyone that has had anything on it fail. I just chose the company that designed the subframe closest to how i would have done it.)
Racing Concepts (yes the site is still up even after all the complaints) kit is $2000. The kit includes tubular subframe with transmission mounting kit, engine mounts, exhaust manifolds, and new steering shaft.
They all seem to be right around the same price wise for what you get. It seems like V8Roadsters kit was designed more for weight savings (which does appeal to a lot of people) while the Boss Frog one seems to be more about strength. I don't know about you, but i want it strong, to last long, so i can get my friction on!
Here are some better photos that i took last night.
Transmission Crossmember:
Subframe (sorry i didn't have any tools inside to take the shipping "feet" off):
Flipped over:
Closeup of some welds:
One side view:
The other side:
And a view from straight overhead:
I hope that helps some people out. I know there are not a lot of photos out there of the Boss Frog kit.
On The Tree
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From: San Anselmo, CA
Thanks for the input on the T56, guys. I am going to go this way for simplicity right now versus experimenting with a T5. I'll respectfully disagree that 50lbs doesn't matter (remember, this is a race car) because as soon as you turn the wheels to go around a corner or go for the brake pedal, the weight of the car is ALL that really matters (HP is irrelevant). A pound saved is a pound saved and will make the car corner faster and will make the tires and brakes (and fuel) last longer. That being said, sacrificing reliability to save ANY amount of weight isn't a good idea. So, in the end, I absolutely agree with your conclusion.
Cheers,
Dean
Cheers,
Dean
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Thanks for the great pictures. From what I'm seeing, It looks like they have a good amount of time fabricating these. There is alot of welding and cutting time there. I see a spot or two that look like they plasma cut an edge and didn't clean it up afterwards (see the sway bar bracket). Still that doesnt affect the strength of the part... could cause caffing issues if something was against it I guess. All in all though it looks like a sturdy part, maybe even over built and probably a reasonably good value. Whats your impression?
Earlier I asked how much the crossmember weighed... What I meant was the engine/front crossmember aka front subframe or k-memember.
Earlier I asked how much the crossmember weighed... What I meant was the engine/front crossmember aka front subframe or k-memember.
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That is pretty much my impression too. A couple rough spots, but if it bothered me that much i could clean them up myself. It definitely seems strong enough. Overall i am happy i went with them. Weighed it really quickly on the house scales this morning. 35lbs. Sorry for the confusion before. Hope that helps.
Staging Lane
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Great info... That thing sure looks like more than 35#... Good to hear that it isnt too heavy. Do you know what the difference in engine placement is between this crossmember and the one from V8 roadsters? I know with the roadsters kit you have to cut the tunnel. Since the BF kit puts it pretty close to the firewall the roadsters kit must mount the engine higher? Maybe more level?
Thanks for the reply.
My wheel tire combos (there are several depending on event) are set. Just asked out of curiosity. I like to have an understanding of things not seen before & those are some really cool wheels.
Great info... That thing sure looks like more than 35#... Good to hear that it isnt too heavy. Do you know what the difference in engine placement is between this crossmember and the one from V8 roadsters? I know with the roadsters kit you have to cut the tunnel. Since the BF kit puts it pretty close to the firewall the roadsters kit must mount the engine higher? Maybe more level?
V8roadster's kit does not mount it higher. It mounts it further to the rear to maintain a better balance(front to rear), clear the factory location of the swaybar and you don't have to add in "crutch" to make the steering shaft work.The cutiing on the firewall is really minimal. I've driven a conversion of their's before and you would be absolutely amazed at the balance and handling of the car as well as how easy it is to put the power down. Their product is (in my opinion) the best on the market and has the most research put into it. Call the guys at v8roadsters and talk to them they are great to work with and have built quite a few of these cars.
Sorry to highjack your thread.
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That is what this thread is about, informative posts like that. Thank you.
Yes i do believe the Boss Frog subframe is going to move the engine a bit more forward, but it seems like they really move the steering rack more than anything to avoid cutting the oil pan. I havn't noticed the V8 roadsters kit using a steering extension or anything, and as such they do require an oil pan modification. Since i have yet to see someone using the Boss Frog subframe, and how it positions the engine in a NA chassis, I am really curious to see how much clearance is given as well as how the weight balance is affected. Since i am mainly going to be taking this car to the drag strip and driving it around town, the minimally affected balance wasn't my highest concern. However if I had an auto-cross track anywhere closeby, you better believe that would have pursuaded my decision a little too.
Yes i do believe the Boss Frog subframe is going to move the engine a bit more forward, but it seems like they really move the steering rack more than anything to avoid cutting the oil pan. I havn't noticed the V8 roadsters kit using a steering extension or anything, and as such they do require an oil pan modification. Since i have yet to see someone using the Boss Frog subframe, and how it positions the engine in a NA chassis, I am really curious to see how much clearance is given as well as how the weight balance is affected. Since i am mainly going to be taking this car to the drag strip and driving it around town, the minimally affected balance wasn't my highest concern. However if I had an auto-cross track anywhere closeby, you better believe that would have pursuaded my decision a little too.
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Question Time!!! Well i started a thread about this in the noob section, but i will ask here too since ya'll have been super helpful.
So i have the 2004 LS1 out of the Corvette which is drive by wire. I have been slowly collecting things to convert it back to the cable throttle since the engine didn't come with any bit of harness or throttle peddle. So far i have:
1999 F-body PCM
F-body throttle body
F-body MAF
Will any 99-02 F-body engine harness work? I was also told that i would need to change the oil pressure sensor to the F-body one, and i was going to go with the 3 wire 1998 coolant temp sensor (easy hookup to a gauge). Any helpful insight is welcome!
So i have the 2004 LS1 out of the Corvette which is drive by wire. I have been slowly collecting things to convert it back to the cable throttle since the engine didn't come with any bit of harness or throttle peddle. So far i have:
1999 F-body PCM
F-body throttle body
F-body MAF
Will any 99-02 F-body engine harness work? I was also told that i would need to change the oil pressure sensor to the F-body one, and i was going to go with the 3 wire 1998 coolant temp sensor (easy hookup to a gauge). Any helpful insight is welcome!
Sorry I dont have the answer to your question but Nathan has a pretty good writeup on electrical using that setup on his. Take a look at his webpage.
http://home.comcast.net/~npartist/electrical.html
http://home.comcast.net/~npartist/electrical.html
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Yeah, i have taken a look at his site before and he does have a lot of useful info. One thing he doesn't have though is converting from drive by wire to drive by cable. It didn't turn up in the search engine, but after looking around i found these threads that pretty much answered my questions. Just linking to them incase anyone else ever has these questions.
drive-by-wire to drive-by-cable
The LS1 swap FAQ has PCM pinouts for 98-02 that you can compare. I have only looked at them briefly but, other than the EGR difference, the 99 and 02 seem to be the same.
drive-by-wire to drive-by-cable
The LS1 swap FAQ has PCM pinouts for 98-02 that you can compare. I have only looked at them briefly but, other than the EGR difference, the 99 and 02 seem to be the same.