what is the max hp for a 550cc pri / 720cc sec combo
11-06-04, 09:24 PM
#1
what is the max hp for a 550cc pri / 720cc sec combo
ok just what the title says. How much hp would be safe with this combo??? Also how much hp is safe on the stock 550/550 combo?
edit: now I'm talking about these injector combos with a fuel pump upgrade and rewire.
edit: now I'm talking about these injector combos with a fuel pump upgrade and rewire.
Last edited by hondahater; 11-06-04 at 09:27 PM.
11-06-04, 10:33 PM
#6
Most I have heard of on the stock inj/pump is 249rwhp from a friend of mine who saw it on the dyno. Spd racing claims he saw 269rwhp on stock inj/walrbo. Personally I maxxed out the stock cleaned inj/walbro @ 11psi on my s4 turbo/motor. I'm not sure on 720s 300-300rwhp safely?
Trending Topics
11-06-04, 11:02 PM
#8
Boosting Again
11-06-04, 11:11 PM
#9
I've seen this calculator before just to dumb to use it correctly. I guess I would just put in the max duty of 550's witch I believe isn't smart to go above 80% right? if that is true than the stock should be good to 250hp. the 720cc's would be good for about 300hp at 80%
oh ok just saw the warning if you go above 85%
so stock would be 270hp and 720cc would be 311hp.
oh ok just saw the warning if you go above 85%
so stock would be 270hp and 720cc would be 311hp.
11-06-04, 11:23 PM
#10
Fuel calculator are kinda worthless unless you know your BSFC....
http://www.maxcooper.com/rx7/how-to/...tem/calcs.html
More accurate site...
http://www.maxcooper.com/rx7/how-to/...tem/calcs.html
More accurate site...
Last edited by Turblown; 11-06-04 at 11:25 PM.
11-06-04, 11:49 PM
#12
Rotorhead
Join Date: Feb 2001
Location: Charlottesville, Virginia, USA
Posts: 9,136
Likes: 0
Received 39 Likes
on
33 Posts
Originally Posted by 1Revvin7
Fuel calculator are kinda worthless unless you know your BSFC....
It's probably not a good idea to mess with your car if you guys don't know this stuff.
11-06-04, 11:54 PM
#13
Moderator
iTrader: (3)
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 30,826
Received 2,591 Likes
on
1,840 Posts
use a bsfc of about .85 on a stock ecu/stock mixture application
11-06-04, 11:56 PM
#14
Originally Posted by Evil Aviator
... and fuel pressure.
It's probably not a good idea to mess with your car if you guys don't know this stuff.
It's probably not a good idea to mess with your car if you guys don't know this stuff.
11-07-04, 09:19 AM
#15
Senior Member
Join Date: Aug 2004
Location: Albuquerque, New Mexico
Posts: 504
Likes: 0
Received 0 Likes
on
0 Posts
Asked same question to my tuner
Asked my tuner, Tom at RotaryRX the same question. He said that without upgrading the exhaust system the benefits on upgrades to fuel system would be minimal. This makes sense to me, as a NooB, since logically it is the fuel and air combination that drive hp. So I'm going with the RB 3" exhaust system and upgrading secondaries to 720s or 750s with a Walpro FP. Also a lightweight steel flywheel.
Is this observation too simplistic?
Is this observation too simplistic?
11-07-04, 09:54 AM
#16
well I mean I would just like to know how much hp is possible out of these injectors, period, with all the mods. I think the general rule of thumb is 550s all around is 250-260 hp where the 720cc secondaries are good for 300-315hp.
11-07-04, 12:36 PM
#17
Moderator
iTrader: (3)
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 30,826
Received 2,591 Likes
on
1,840 Posts
720's are about 15% more fuel, so that gets you from about 250 to 285
11-07-04, 12:54 PM
#19
RX-7 Alumni
Originally Posted by j9fd3s
720's are about 15% more fuel, so that gets you from about 250 to 285
BTW 250-269 hp is a big range, I think the correct number is 250 for the stock setup. Sure some people go more--but they are rolling the dice. Remember fuel requirements depend on many factors and 9/10 times could be OK, but it just takes that one set of conditions to pop your motor.
HTH,
Scott
p.s. I'm running that exact setup with the Rtek 1.7
11-07-04, 06:42 PM
#22
EIT
Join Date: Jan 2002
Location: Austin, TX
Posts: 1,790
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by hondahater
from what I've heard the that 58% deal is just a myth!
There is however a raw afm limit before the secondaries come online. This is all covered in henriks various threads on teamfc3s.
With stock fuel pressure and 11:1 air fuel ratio, I believe a 550/720 combo will max out a little north of 270. (had a typo in the other thread covering this) This is a conservative estimate, but it's somewhere in the ball park.
What I really would be worried about is being able to run lean before the secondaries come online. I know the rtek ecu has the secondary activation point dropped a few hundred rpms, but with a large hybrid turbo it's still feasible to be making some serious boost before the secondaries can come online even on the modified ecu.
11-07-04, 07:06 PM
#24
EIT
Join Date: Jan 2002
Location: Austin, TX
Posts: 1,790
Likes: 0
Received 0 Likes
on
0 Posts
I have no idea. I haven't been to a dyno in nearly a year and a half. I'll try and get an old IC kit on the car then take it the dyno by spring sometime. I do plan on taking it to the track again this thanksgiving. It feels like a high 12/low 13 second car right now. I'm expecting a trap speed of around 108-109.