Swapping in a Cosmo motor (2 rotor)
02-09-03, 03:42 PM
#31
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It's really just temporary until I can scrape up enough for an all-out Pineapple motor really...I daily drive the car so down time is not an option. I took a peek inside the Cosmo engine through the exhaust sleeves and the innards, from what I could see, it looked ok. Like I said, it's an experiment. I've seen quite a few guys with remans that blow in short order too. It comes with a good compression/running order guarantee as well, so if we get this in and it's a dud, I'm covered.
One thing I've noticed is that the port shape, while being larger, is also angled into the combustion chamber differently than the REW. I don't know which is better.
I was hoping to have everything started on Monday and have the installation complete by Friday Yanni. I'll be recouping from the surgery then but I'm not going to have all the funds necessary to do the swap thanks to medical insurance deductables, sigh...I'm not just swapping in the motor, but doing a few other things while I'm "in" there like a clutch, large oil cooler, etc. My big plans were to attend rotorfest but that just ain't happening now.
IMHO the turbo is too big, LOL. I took a ride in an untuned T04S equipped vehicle yesterday and we then went for a drive in my car, blown engine et al. I definitely had a hp advantage. The turbo really kicks in hard where the T04 seems to come in earlier and softer and maintain with an ok top end. The GT79's top end is pretty crazy in comparison. Naturally the To4 will get better once it's been tuned more thoroughly. The maps are purposely a bit rich until I can get a wideband hooked up to his car and do a little tuning.
Michel
One thing I've noticed is that the port shape, while being larger, is also angled into the combustion chamber differently than the REW. I don't know which is better.
I was hoping to have everything started on Monday and have the installation complete by Friday Yanni. I'll be recouping from the surgery then but I'm not going to have all the funds necessary to do the swap thanks to medical insurance deductables, sigh...I'm not just swapping in the motor, but doing a few other things while I'm "in" there like a clutch, large oil cooler, etc. My big plans were to attend rotorfest but that just ain't happening now.
IMHO the turbo is too big, LOL. I took a ride in an untuned T04S equipped vehicle yesterday and we then went for a drive in my car, blown engine et al. I definitely had a hp advantage. The turbo really kicks in hard where the T04 seems to come in earlier and softer and maintain with an ok top end. The GT79's top end is pretty crazy in comparison. Naturally the To4 will get better once it's been tuned more thoroughly. The maps are purposely a bit rich until I can get a wideband hooked up to his car and do a little tuning.
Michel
02-14-03, 08:36 PM
#32
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just a quick update, I may have the engine rebuilt and the exhaust sleeves ported extensively. I think it'll be good insurance and will give me a killer engine until I can finish with the three rotor details.
Michel
Michel
12-07-03, 07:48 AM
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Originally posted by rx7tt95
Oh and the stock Cosmo turbos..one is the same Hitachi unit found on the FD, the primary, and the secondary is a larger unit. I haven't pulled them apart to check their condition, but when I do, I'll see if they mate up to the FD manifold. Might be a nice affordable upgrade for someone running twins.
Oh and the stock Cosmo turbos..one is the same Hitachi unit found on the FD, the primary, and the secondary is a larger unit. I haven't pulled them apart to check their condition, but when I do, I'll see if they mate up to the FD manifold. Might be a nice affordable upgrade for someone running twins.
The RX7's Hitachi HT-12 are identical turbo cartridges for the primary and secondary and employ high-flow curved turbine blades for a 20% greater flow volume compared to the Cosmo turbos. Also, the smaller number of impellers equates to faster spool times due to weight and inertia.
Also remember that the Cosmo engine was only mated with an automatic transmission. Many of the designs of the motor are used to maximize the performance/efficiency when using the auto tranny. No manual transmissions were offered.
Good work otherwise with the conversion. I was thinking about doing this two years ago and decided not to pursue it. Glad to see all of the information gathered.
Tim
12-07-03, 08:40 AM
#34
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It would be a damn shame for you to use the FD UIM and LIM. I mean, it would almost defeat the purpose of getting the cosmo to begin with.
If I were in your shoes.....
I'd try to just stick in a used 13b-rew in the FD for now. Leave the Cosmo on the side and get it built up PROPERLY. I don't know about you, but if I had that Cosmo and I installed it with the FD manifolds, I'd be going haywire wondering about the Cosmo manifolds.
Those intake ports are HUGE. They almost look like one additional port was added to each rotor. Let alone the fact that those are STOCK ports. I wonder how big they can get when ported
What ever your plans are for now, I'm sure someday you will end up building the snot out of it
If I were in your shoes.....
I'd try to just stick in a used 13b-rew in the FD for now. Leave the Cosmo on the side and get it built up PROPERLY. I don't know about you, but if I had that Cosmo and I installed it with the FD manifolds, I'd be going haywire wondering about the Cosmo manifolds.
Those intake ports are HUGE. They almost look like one additional port was added to each rotor. Let alone the fact that those are STOCK ports. I wonder how big they can get when ported
What ever your plans are for now, I'm sure someday you will end up building the snot out of it
12-23-04, 10:47 PM
#36
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Motor is holding up just fine! I still feel I need to find a good turbo match, maybe something Sean is coming up with early next year. It's powerful enough as is...I've had a 406rwhp and a high 390rwhp dyno. Motor doesn't fall off up top like most dyno graphs, more than likely due to the ported LIM. I have a feeling with the right turbo, she'd be just killer. I did manage to lay waste to an S55 AMG (as in 490+hp) from a rolling start off boost in first gear no less...AND just before that, an Audi S4. All within the space of about 3 minutes. Blew away the S4 and I blew by the the S55 while decelerating who then decided he wanted to have a go as well.
Good info on the Hitachi's. I later learned the differences but didn't post. Not too sure on the Cosmo vs. FD intake...talking to a few hard core racers, the Cosmo intake builds peak torque sooner which may be of benefit on the street. Being the Cosmo was an auto and heavier than the FD, torque was of more concern. Most of the motor internally, however, is identical to the FD with the intake/exhaust ports being the major differences. With a bit of porting, they "adapt" quite well to use in an FD :-) Used Cosmo cores were for me, less expensive, and more than likely in better shape (mine was virtually mint internally with very little wear).
The biggest issue with the motor has been getting the oil pan to seal. Ended up using one of Gotham's oil pan braces which solved the issue. I'd use that or go with the A-spec oil pan if you go with a Cosmo 'block".
Here's a dyno sheet from Steve Kan's tuning session (mid 10's afr and 14 degrees split). This is with the GT4082 which NYT deems too small. I'm not in total agreement with that assessment as it seems to work quite nicely but it may not be the perfect turbo for a 400+ FD. I'm much happier with it than I was with the modified T78. The T78 had much better top end however (think sideways in third) but was a dog below 4K. I think the larger ports like a bit larger turbo.
Good info on the Hitachi's. I later learned the differences but didn't post. Not too sure on the Cosmo vs. FD intake...talking to a few hard core racers, the Cosmo intake builds peak torque sooner which may be of benefit on the street. Being the Cosmo was an auto and heavier than the FD, torque was of more concern. Most of the motor internally, however, is identical to the FD with the intake/exhaust ports being the major differences. With a bit of porting, they "adapt" quite well to use in an FD :-) Used Cosmo cores were for me, less expensive, and more than likely in better shape (mine was virtually mint internally with very little wear).
The biggest issue with the motor has been getting the oil pan to seal. Ended up using one of Gotham's oil pan braces which solved the issue. I'd use that or go with the A-spec oil pan if you go with a Cosmo 'block".
Here's a dyno sheet from Steve Kan's tuning session (mid 10's afr and 14 degrees split). This is with the GT4082 which NYT deems too small. I'm not in total agreement with that assessment as it seems to work quite nicely but it may not be the perfect turbo for a 400+ FD. I'm much happier with it than I was with the modified T78. The T78 had much better top end however (think sideways in third) but was a dog below 4K. I think the larger ports like a bit larger turbo.
12-23-04, 10:49 PM
#37
Originally Posted by rx7tt95
Motor is holding up just fine! I still feel I need to find a good turbo match, maybe something Sean is coming up with early next year. It's powerful enough as is...I've had a 406rwhp and a high 390rwhp dyno. Motor doesn't fall off up top like most dyno graphs, more than likely due to the ported LIM. I have a feeling with the right turbo, she'd be just killer. I did manage to lay waste to an S55 AMG (as in 490+hp) from a rolling start off boost in first gear no less...AND just before that, an Audi S4. All within the space of about 3 minutes. Blew away the S4 and I blew by the the S55 while decelerating who then decided he wanted to have a go as well.
Good info on the Hitachi's. I later learned the differences but didn't post. Not too sure on the Cosmo vs. FD intake...talking to a few hard core racers, the Cosmo intake builds peak torque sooner which may be of benefit on the street. Being the Cosmo was an auto and heavier than the FD, torque was of more concern. Most of the motor internally, however, is identical to the FD with the intake/exhaust ports being the major differences. With a bit of porting, they "adapt" quite well to use in an FD :-) Used Cosmo cores were for me, less expensive, and more than likely in better shape (mine was virtually mint internally with very little wear).
The biggest issue with the motor has been getting the oil pan to seal. Ended up using one of Gotham's oil pan braces which solved the issue. I'd use that or go with the A-spec oil pan if you go with a Cosmo 'block".
Here's a dyno sheet from Steve Kan's tuning session (mid 10's afr and 14 degrees split). This is with the GT4082 which NYT deems too small. I'm not in total agreement with that assessment as it seems to work quite nicely but it may not be the perfect turbo for a 400+ FD. I'm much happier with it than I was with the modified T78. The T78 had much better top end however (think sideways in third) but was a dog below 4K. I think the larger ports like a bit larger turbo.
Good info on the Hitachi's. I later learned the differences but didn't post. Not too sure on the Cosmo vs. FD intake...talking to a few hard core racers, the Cosmo intake builds peak torque sooner which may be of benefit on the street. Being the Cosmo was an auto and heavier than the FD, torque was of more concern. Most of the motor internally, however, is identical to the FD with the intake/exhaust ports being the major differences. With a bit of porting, they "adapt" quite well to use in an FD :-) Used Cosmo cores were for me, less expensive, and more than likely in better shape (mine was virtually mint internally with very little wear).
The biggest issue with the motor has been getting the oil pan to seal. Ended up using one of Gotham's oil pan braces which solved the issue. I'd use that or go with the A-spec oil pan if you go with a Cosmo 'block".
Here's a dyno sheet from Steve Kan's tuning session (mid 10's afr and 14 degrees split). This is with the GT4082 which NYT deems too small. I'm not in total agreement with that assessment as it seems to work quite nicely but it may not be the perfect turbo for a 400+ FD. I'm much happier with it than I was with the modified T78. The T78 had much better top end however (think sideways in third) but was a dog below 4K. I think the larger ports like a bit larger turbo.
12-24-04, 07:06 AM
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I'd say it's better for torque surprisingly but that's just based off what I've heard from racers. The upper intake manifold and throttle body are stock but the lower LIM is ported/port matched to the Cosmo ports. There was BARELY enough room to do this with the bumps in the casting but it seems to be working. I read way back when the stock throttle body and intake was fine up to 550hp or something around there, from one of Adam S's old articles but the lower definitely needs work. I've considered trying that new LIM with the larger runners and extrude honing the upper. I may do that the next round.
12-28-04, 09:17 AM
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(The biggest issue with the motor has been getting the oil pan to seal. Ended up using one of Gotham's oil pan braces which solved the issue. I'd use that or go with the A-spec oil pan if you go with a Cosmo 'block". )
I tapped the rear housing using 1/2x1.125" and (1.250") bolts so I could use the stock pan and mounts. The turbo side required longer bolts due to the location of the old pan bolt tapped threads on the RE pan. (My pictures are too large)
Barry
I tapped the rear housing using 1/2x1.125" and (1.250") bolts so I could use the stock pan and mounts. The turbo side required longer bolts due to the location of the old pan bolt tapped threads on the RE pan. (My pictures are too large)
Barry
12-28-04, 10:16 AM
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We thought about doing that but we were concerned with the amount of material in that area. How long have you been running the Cosmo with the tapped oil pan bolt holes? No issues at all?
12-28-04, 12:04 PM
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I am running a Garrett GT4082 plain bearing turbo which someone has found to be too small. It seems to work very well for me however so not too many complaints. I'd actually like a bit more bottom end but the midrange hit is awesome. Top end is very good, not as good as my last turbo, a modified T78 featuring a larger 93mm wheel. I'm POSITIVE I had about 50 more hp in the upper ranges with that turbo but at the sacrifice of the bottom end and even some of the midrange. I'll probably be swapping turbos, either a PT61 or something Sean at A-spec is working on (top secret!).
12-28-04, 01:49 PM
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How much did the cosmo motor run you including all the extras you had to do.... From begining to end of the project?
Is this motor more reliable than the original 13B?
Is this motor more reliable than the original 13B?
12-28-04, 02:14 PM
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Internally, there are very few differences between the 13BREW in the third gen and the 13BRE. The REW motor is the newer design. I essentially had to swap out the exhaust sleeves (free except for removal of the sleeve pins $100) for FC (or FD) sleeves and then port-match the FD's LIM to the larger Cosmo ports which I did myself. The engine cost about $1600 low mileage and I was able to sell off a number of the parts incuding the Cosmo LIM and UIM. IF I were to do it again, I'd probably keep the Cosmo intake and put it on to see "what if?". Originally I was not going to pull this engine apart, merely slap it in and be done with it. Changed my mind in the end and rebuilt it even though it was in great shape when we opened her up. Also needed the oil pan brace and different mounts. The mounts were about $225 or so.
