s4play

I currently have a 93 r1, with a dp, cb, intake, apexi computer and mild street port. the car is fast but I would like some more power in the LOW rpm range, what suggestions do you have. I am thinking new radiator and possily intercooler but have tossed around the idea of upgraded twins. Don't want to do a midpipe but a high flow cat is possible although I thinks this helps top end rather than low.

Any suggestions would be great from redo suspension to go single but again please note this is a road racing car and nt a dragster, also needs to be streetable.

PS almost all reliability mods done.

Rated R1

That is definitely a tough problem to fix. I think one way to solve the lack of low end torque our cars have is with a ball bearing type turbo that has less lag than the stock twins such as the M2 twins or the ball bearing apexi single turbo (RX6?, I'm not to hip to singles).

s4play

Thanks, the current low end power is good I guess I would be happy if the mods I did made the SAME low end power but more overall power.

Mahjik

iTrader: (1)

I think you would be ok with a hi-flo cat. Also, I noticed more turbo response when I upgraded my IC (quicker spooling). That may be an option for you.

I'm not a fan of the single turbo upgrade, so I can't help you there...

rynberg

The only thing that will spool faster than the stock twins is the M2 ball-bearing twins. If you want to retain low-end and gain high-end, install a medium SMIC. I haven't seen enough dyno comparisons with a hi-flow cat vs stock to see if you lose any low-end. Definitely don't get a midpipe. Also, I don't think the radiator is going to help you either...

BTW, what cat-back do you have? Some are more biased toward high-end power than low and mid.

Other than that, just increasing the boost will raise your overall power.

s4play

Interesting thanks for all the positive feedback. I have a PFS CB (came with the car). the radiator mod would just help keep the temp down I think. I am going to post a question about T&R in Queens in a new thread so if anyone has an opinion let me know. Thanks again.

RX7Elmo

i feel the twins/motor has good power above 3000rpm really. Or do you intend to have more power below that? I dont' think a hi-flow will lose that much low end but does gain a lot onn the high end compaed to a midpipe.

What kind of boost controller do you have? Some electronic ones have solonoieds that can give you very fast response as well.

Danny

s4play

no boost controller I thought the apexi power fc mitigated the need for a boost controler. I am still a newbie to this and have seached ALOT (prop too much cause I am totally confused on most topics)

RX7Elmo

the PFC is a boost controller that controls the stock turbo solenoids. If you buy the adapter for it or a profec b, it comes with it's own solenoids that better controls boost. I'm sure boost control is not your problem though.

but yeah, low-end in a rotary is a hard one, it was designed for more high end kick.

Danny

Lunar7

I know what you mean as the 400HP cars like Vipers, Z06 and 996 will pull on us exiting the turns.
The 996 will also seriously out brake us.

I found that we can often carry more speed in the turns than they do.
If you upgrade your brakes you might be able to keep those cars in your rear view mirror or intimidate them enough in the turns to let you by.
Killer brakes let you stay on the boost longer which is almost like a power mod.

As for your power I think a med size (low lag/pressure drop) intercooler will help you as well as a High Flow Cat.
In my case I always noticed low end HP gains with exhaust mods.

I would not do a turbo upgrade if your stock twins are still working.
They are hard to beat on the low end.

Big Brakes and HF Cat are my next mods.

s4play

cool again thanks all. It might be time to give dave the key for a couple of cold months and let him work some magic

rynberg

You don't need a boost controller with the PFC. BTW, you should talk to Max Cooper if you're interested in road racing. He has the Apexi RX6 single turbo and does a lot of racing. DamonB and SleepR1 also do a lot of racing but I think both of their cars are fairly stock in the power department. I'm sure they could give good advice regarding suspension, tires, and reliabilty issues.

JONSKI

Do the turbo simplification and remove your ACV, DT, AWS, and EGR. I swear I have more low end power, but it didn't fix my boost problem like I had hoped.

xchaos

Another option may be rearend gearing.

s4play

again very good ideas, non sequential giving more low end now that is kind of wierd.

Mahjik

iTrader: (1)

He didn't mean run non-seq, he just meant the simplification (which still retains seq operation). Not that I think that will add any power.

Pulleys may help free up a little low end power, but you won't notice it a whole lot. But heck, every little bit helps.

s4play

ok not sure what jonski is talking about will do some research and come back

RX7Elmo

http://www.rx7turboturbo.com/robrobi...lification.htm


Check the above. I might go and tackle this job too.

Danny

s4play

OK waaaayyyyy to compicated for me to do myself. The gearing issue and flywheels sound like really good, easy ideas.

OptusX4

yeah, just get a lower geared rear end, and throw a kaaz in there while you're at it

m0t03

If you wanted tons of low end you shouoldnt have gotten a turbo car. anyways if you just shift higher you will be in the power more often than not. Dont get a MP, although I think its one of the best mods Ive done. maybe get a highflow cat but I think they might take a little out of your low end too. BB turbos would help lots, but for the money I would rather buy a single turbo.

s4play

Thanks but why would you want a single turbo for road racing?

JONSKI

Just remember to leave the Fuel Pressure Regulator solenoid intact. It's not in the diagram. The FPR solenoid is the one closest to the firewall with an orange plug. It has one hose going to the inside of the LIM and the other going to the FPR on the firewall end of the secondary injector rail. Also, if you remove your ACV, then your airpump will have no place to pump air, so you might as well unplug it, so that it freewheels. Your exhaust will stink at low revs without the airpump.

foko

i run the apexi single on the road race car and, while i don't have documentation, it seems to spool as well as the stock setup. realistically, its easier to stay in the power band (be it big single, small single, sequential, N/A) on the track than on the street. if you raced hard core, you'd adjust your gearing based on the specific track. otherwise you just shift more.

don't go single if you have to deal with emmissions testing....major PITA.

singles are much simpler and easier to diagnose when problems arise but easier to ruin an engine with if you mess up.

as far as a better setup for road racing......

you will improve lap times much more cost effectively by improving the chassis of your car than by putting down big horsepower.

and remember, the ultimate modification is to learn how to drive for real.

so....mods in this order
1. driving school or equivalent
2. reliability ie...engine temperature management
3. tire/wheel
4. suspension upgrade/tuning
5. brakes
6. power

good luck to ya
fabian

Kahren

iTrader: (13)

low end? what rpm do exit the corners? its usually above 5k unless you dont downshift right before the corner?