November 17, 2019, 06:01:22 AM

Author Topic: Whats the new hot engine combo for rx7  (Read 5103 times)

Offline digitalsolo

  • Administrator
  • Top Fuel
  • Location: Fort Wayne, IN
  • Posts: 22848
  • View Gallery
    • View Profile
    • LS1FC.com
Re: Whats the new hot engine combo for rx7
« Reply #75 on: November 07, 2019, 01:10:36 PM »
You need a pretty good sized cam and really, really good heads (and probably 400+ cubic inches) to get 550 RWHP most likely, IMHO.     And probably good rockers, etc, etc.    It's not super cheap.
Blake MF'ing McBride
1988 Mazda RX7 - Turbo LS1/T56/ProEFI/8.8/Not Slow...   sold.
1965 Mustang Coupe - TT Coyote, TR6060, modern brakes/suspension...  project car
2016 BMW 428i xDrive Gran Coupe - Completely stock...ish

Offline wickedrx7

Re: Whats the new hot engine combo for rx7
« Reply #76 on: November 07, 2019, 02:01:53 PM »
You can get to 550 on an ls3 but it is going to take all the things including a big cam... which makes drivability an issue.

Why not just spray your motor? Itís built for it, gives you some instant gratification and would be pretty cheap to install.

Or you could buy an LT2. Would love to see one in an FD.

1993 Touring, 2012 L99, T-56, Ronnin 8.8, Ohlins, Speedhut, Samberg and lots of custom parts
Build Thread - http://www.norotors.com/index.php?topic=19354.0
Pictures - www.flikr.com/wickedrx7

Offline Exidous

Re: Whats the new hot engine combo for rx7
« Reply #77 on: November 07, 2019, 02:49:47 PM »
I'm doing a used LS7 rotating assembly, having a gen 4 5.3L sleeved to 4.125", LS7 heads and intake. A mild mid 230-240 cam should net 550whp or so.
94 BB SBE LS1 Full Mamo top, MS3ProU with TC, RONIN 8.8 and another custom dual 2.5" stainless exhaust. Not too loud with the new resonators!

Offline jwvand02

Re: Whats the new hot engine combo for rx7
« Reply #78 on: November 07, 2019, 08:39:01 PM »
I'm doing a used LS7 rotating assembly, having a gen 4 5.3L sleeved to 4.125", LS7 heads and intake. A mild mid 230-240 cam should net 550whp or so.
In practice, how does this differ from a factory LS7?

Offline Exidous

Re: Whats the new hot engine combo for rx7
« Reply #79 on: November 07, 2019, 10:48:24 PM »
No oil squirters, far stronger cylinder walls and no dry sump. The lack of dry sump is only a matter of parts external to the block. Pan, pump, front cover and reservoir.

The f-body pan had almost an inch more clearance at the steering rack but I believe you can modify a dry sump pan to work.

Oh and the block says 5.3 rather than 7.0...

I may have gotten the deal of the year on the heads. Fresh WCCH ported LS7 heads with bronze guides and new stainless exhaust valves for $750 shipped. Factory titanium intake valves.
94 BB SBE LS1 Full Mamo top, MS3ProU with TC, RONIN 8.8 and another custom dual 2.5" stainless exhaust. Not too loud with the new resonators!

Offline paul_3rdgen

  • Supporting Member
  • Launching!
  • Location: Canada
  • Posts: 1129
  • View Gallery
    • View Profile
Re: Whats the new hot engine combo for rx7
« Reply #80 on: November 08, 2019, 06:33:23 AM »
^ If I remember correctly you can add oil squirters in.  Is it worth the hassle?  Whatís the displacement going to be 427? Or are you trying to build a destroked ls7 388ci, like Detroit speed put in their 3rdgen Camaro?  650 crank hp, at 8000rpm.  If I had the money, I think thatís what I would be building.  I feel it would be a perfect fit for our cars.   

Didnít 65imp do this many years back?  Maybe he can chime in on how it all worked out. 


Sent from my iPhone using Tapatalk
93 RX7 R1 500rwhp
LS2, H/C combo... ARE drysump
Race Logic traction Control and 4 wheel Stoptech BBK
3.73 gears installed in the stock diff  :o

Offline largeorangefont

  • Top Fuel
  • Location: So Cal
  • Posts: 6622
  • I steer with the gas pedal.
  • View Gallery
    • View Profile
Re: Whats the new hot engine combo for rx7
« Reply #81 on: November 08, 2019, 08:20:12 AM »
Do we think the magnum is 15% drive train loss?  So if we want 550WHP we need 650 FWHP.

Does a mild cam NA motor with 650 FWHP recipe exist? 

LS7 and lopey cam makes that easy. 
LS3 needs Heads/valve springs, bigger cam, ported intake
Sleeved 5.3 into a 427/454 with a mid range cam
etc..


None of these are less then $15K unless your building from used either. 

I have $8k budget in my head, guess I need to adjust expectations lol

You just need nitrous and spend the other $6k on something else.
Quote from: cool
Sell it to spacevomit.  He'll finish it.

Offline kinger

Re: Whats the new hot engine combo for rx7
« Reply #82 on: November 08, 2019, 10:37:44 AM »
Do we think the magnum is 15% drive train loss?  So if we want 550WHP we need 650 FWHP.

Does a mild cam NA motor with 650 FWHP recipe exist? 

LS7 and lopey cam makes that easy. 
LS3 needs Heads/valve springs, bigger cam, ported intake
Sleeved 5.3 into a 427/454 with a mid range cam
etc..


None of these are less then $15K unless your building from used either. 

I have $8k budget in my head, guess I need to adjust expectations lol

You just need nitrous and spend the other $6k on something else.

I just hate nitrous.  Short lived and I always want to "save" it not sure why so I never sprayed it when I had it.  (past cars, and even snowmobile)

I want that all the time power with gas and go, which is pretty much what I have LOL  I just like seeing what people are doing and what they think is optimal. 

8K rpm is so hard on stuff not sure I want that just because the rotary was a high rever. 

I think a 427 or 454 is perfect for my tastes.  I like that 2-4K grunt, after 4K I'm already speeding on the street and have to let off.  If I stay in it now its triple digits so fast I'm going to get in trouble lol. 
93 Touring, 6.3L, T56 Magnum, Mamo RPS BC2 clutch, FAST 90, NW 90TB TB, 8.8, samberg everything, AC, PS, TC, Cruise, LED Tails, HID head lights

Offline Exidous

Re: Whats the new hot engine combo for rx7
« Reply #83 on: November 08, 2019, 10:57:44 AM »
^ If I remember correctly you can add oil squirters in.  Is it worth the hassle?  Whatís the displacement going to be 427? Or are you trying to build a destroked ls7 388ci, like Detroit speed put in their 3rdgen Camaro?  650 crank hp, at 8000rpm.  If I had the money, I think thatís what I would be building.  I feel it would be a perfect fit for our cars.   

Didnít 65imp do this many years back?  Maybe he can chime in on how it all worked out. 


Sent from my iPhone using Tapatalk

I'll still be keeping it at the 427. I have the 4" crank, rods and pistons already. An 8000RPM destroked LS7 would be amazing. The ITB's or sheet metal intake and valve train to do it reliably would be too much to swallow though. Maybe a short runner FAST square port could carry that high but I doubt it.

Down the raid if I ever want to change things up I can take the block out to 4.185" or even 4.2" then destroke it. Would net a pretty crazy 401ci.
94 BB SBE LS1 Full Mamo top, MS3ProU with TC, RONIN 8.8 and another custom dual 2.5" stainless exhaust. Not too loud with the new resonators!

Offline 65imp

Re: Whats the new hot engine combo for rx7
« Reply #84 on: November 08, 2019, 12:14:36 PM »

Didnít 65imp do this many years back?  Maybe he can chime in on how it all worked out. 

I sure did.  The idea is a little less torque down low since I built my car to be light, I wanted all the help I could get with traction.  Emphasis was on letting it breathe, and keeping internals light. 
Unfortunately I cant chime in much as for how it works, since my car has primarily served as a fitment mule for Ronin.  Last year I went through troubleshooting some systems since I was only firing on 1 bank of cylinders.  I rewired the harness and eliminated my quick disconnect connectors in case they were the culprit, went with a lithium battery, replaced my subframe, and eliminated my accusump.  Still only ran on 4 cyl.   >:(
I have a list of stuff to check, but Ronin customers come first, same with dev. of cool new stuff for Ronin.  Not to mention keeping my vehicles that can get the kids to school on the road...  It will get done, I just have to accept a longer timeline. 
absolute power corrupts absolutely  :yay:
93 FD widebody - destroked
69 Suburban - positive manifold pressure
72 Blazer - 6speed 4wd
65 Impala - 5.7
59 cad  - WIP
53 spartan - shed status

Offline Exidous

Re: Whats the new hot engine combo for rx7
« Reply #85 on: November 08, 2019, 08:58:37 PM »
That's either power to the injectors or power/ground to the coil sub-harness but I'd imagine you checked that.
94 BB SBE LS1 Full Mamo top, MS3ProU with TC, RONIN 8.8 and another custom dual 2.5" stainless exhaust. Not too loud with the new resonators!

Offline MPbdy

Re: Whats the new hot engine combo for rx7
« Reply #86 on: November 09, 2019, 04:29:48 AM »
Is it random cylinder firing or always the one bank? Random is limp mode.

Offline Tomo

Re: Whats the new hot engine combo for rx7
« Reply #87 on: November 14, 2019, 11:39:02 AM »
Just to be a bit different.

Companies like TogueFactory are starting to look at the K20/ K24 series of engines as swap candidates for things like the 240SX and even R32 GT-R. These motors were used in a very wide variety of Honda vehicles and have the "correct" rotation of the crank to be used with other applications (unlike a lot of other honda motors).

The K24 I think actually could make a pretty compelling FC swap candidate if not FD. Lots of parts, strong block, good factory internals on certain vehicles, and more highly available than a lot of other blocks like SR20 etc.

Thoughts?
1990 RX-7 FC LS1 Swap
2016 Ford Mustang Ecoboost

Offline kinger

Re: Whats the new hot engine combo for rx7
« Reply #88 on: November 14, 2019, 11:53:34 AM »
How much weight difference is there between a dressed LS aluminum and a K series motor of similar power? 
93 Touring, 6.3L, T56 Magnum, Mamo RPS BC2 clutch, FAST 90, NW 90TB TB, 8.8, samberg everything, AC, PS, TC, Cruise, LED Tails, HID head lights

Offline Supe

Re: Whats the new hot engine combo for rx7
« Reply #89 on: November 14, 2019, 12:32:09 PM »
430 lbs for dressed naturally aspirated aluminum block LS, 300 for dressed K24.  Add 30# for turbo before hot/cold side piping on the K24, you're looking at less than a 100# delta.