how does one draw that conclusion? For the most part, the same people that ruin their turbos are the same people that dont mod their car correctly and are ultimately the same people that whine like little girls when their engine goes!

i am not taking any side to this debate! i am just curious how this conclusion was made in the first place?

 

A turbo operating outside of its efficiency range will produce more heat as boost increases. (And will eventually produce less power for each incremental boost increase because of the increase in generated heat.) A bigger intercooler can compensate somewhat but there are limits.

That said, as you suggest, I think someone willing to run stock twins at 15 psi is not generally concerned with reliability.

 

what if you increase the efficiency of the turbo via an ic with less pressure drop (an old m2 medium or large comes to mind) and a free flowing exhaust? thus running 15psi is more like 12-13psi on a stock setup.
an upgraded ic does more than simply cooling better.i think thats the thing alot of people forget about while drawing a conclusion on this topic.

 

why are you so fascinated with the rx7 store numbers?

if you want a fast car, theres a well proven safe way to do it...

 

The later design M2 large IC has a very low pressure drop relative to stock so could compensate. I'm running an M2 large with stock turbos at 14 psi and am hitting 90% injector duties on the stock injectors with 11:1 AFRs under boost and reasonable intake temperatures. So there is margin for more boost with upgraded injectors (or higher duties). Pushing things to the edge is not something that is necessarily sensible with this car though.

 

i made 340rwhp with dp/mp/ported wg/large smic w/ duct at 15.5psi on stock turbos and this is with 2.5 inch catback 10afr

 

intresting.. reason im questioning it is that people say its not easy and reliable to do this.. yet rx7store is claiming there mods get u there and is reliable...

so why cant i get around that level and stay reliable..?

 

My friend (Dr.Hagner) ran 370whp on the stock twins and pettit ecu for 4 years before upgrading to a single. This was pumpgas and weekly supra beat downs. The old owner of this forum can vouch.

 

viking can you get me any specs on his setup? as far as bolt ons, and boost level etc?!! thats freakin awesome numbers!! i hope steve kan can get me some nice numbers this november on tuning day!!

 

Stock twins, Non Sequential, Blitz Front Mount, Stock 550 Primaries, 1200cc Secondaries, Pettit Ecu, Apex N1 Dual Catback, Midpipe, Pettit Downpipe and a Stock Supra Fuel Pump. I don't remember if he had a aftermarket fuel pressure regulator or not.

 

wow thats deep.. thanks monson.. im realy not looking to go whip the crap out of the viper down the street or go pull 10 sec et's.. thats really not my goal..

my goals are simple and thats to have a very fun quick street car that i dont have to rebuild every year. general maintence is one thing but rebuilding my setup all the time is something else..

I have purchased near everything i can think of to make my twins all they can be! only thing im missing is a ported motor and the single turbo setup.. id like to use the twins for a while till i do learn my car know exactly what i want to do with it etc.. then i can stay where i am, or upgrade and go single.. either way i dont want my motor blown shortly after getting it in.. over something stupid..

thanks for the help man!

 

i'de stay with a smic ic when maxing out the twins. i think its a better setup with less pressure drop and minimizes lag.

 

i already have a front mount 3 row from greddy installed. just my motor isnt in yet.. been having a lot of thoughts on it deciding what route to go..

 

why is that? are we talking avg hp here?

 

ok tired of ***** footing around....

if those truly are your goals then let me make this simple for you. make sure you have all the boltons (with fully opened up exhaust and hks twin power), def do the fuel mods NO MATTER what anyone tells you (this means stock primarys with 1300 cc secondaries), keep the turbos in sequential mode NO MATTER what anyone tells you( there is no way to compare the fun and INSTANT boost of the sequential system compared to parallel. i dont care if you are talking rich mans, poor mans, billionaires, setup either. lastly and most importantly crank the boost to 15 psi everyday (forget about a low setting as you wont use it). the sequential system is sick. i pull on big v8s (both cobras and z06s) with double my torque on the punch from a roll. i have also beat a 400 rwhp single rx7 with my twins maxed out....on the high way no less. the value you here is one flat hp chart....not peaky.

the 14 psi limit is a myth that is based on zero real world data. on the stock ic sure its a bit much but on a good smic with minimal pressure drop is like running 13 psi. the message here is spend an extra 750 bucks total on the best of breed parts (this means m2 cold air intake coupled with m2 smic's and the hks twin power) and you will be one happy mother f'er and can drive the car with piece of mind rather than constant gauge watching. enjoy....u can thank me later when you post a thread how you left, not beat, LEFT a z06.

there will be some guys that rebut this post with efficientcy talk but from what i ahve read all these tests are with the factory smic.

or as others have said to f it go single....a nice turbo can yield 450 pretty easily and with minimal lag.

 

Then why the hell do you keep wanting to push everything to the limit? As gmonsen stated, 300-320 whp is what you can typically expect with all bolt-ons. Yes, people have got 350 or even 400 whp but there are also people who smoke two packets of cigarettes per day and live into their 90s. There are dozens of threads on this board from people who went to a dyno with all bolt-ons expecting mid 300s whp and instead got ~300 whp (or even less). Expect 300 whp and be pleasantly surprised if you get more. And have you driven an FD with 300 whp?

 

people need to remember dyno numbers are different from motors, to temp, to day, to even hours.. Also take into consider the dyno, dynojet provide the highest number, while mustang and dyno dynamic are ususally 10-15%lower in the readings... Only real comparasion is same dyno same day with very similar mod. Rx7store kit is rated to what they achived, it is ment to be a basic expectation, not tell all end all...

 

Just a FYI, I've had Steve Kan come to St.Louis numerous times for tuning.

From what I've seen, the average HP number for twins with all the supporting bolt on's has been about 350, this is on a dynopak which reads a tad bit lower than a Dyno-Jet.

 

can you get by with stock injectors with that power level if i up the fuel pressure some with a 4:1 fmu or just set it 10-15psi higher with a fpr? id hate to get 1300cc injectors, i hear they dont work well and or break easy, and 850cc primarys have an issue with making it run rich.

 

I ran 500+ hp with 1300's for a few years without any problems. Seeing what you want to do, get some nice used 1300 injectors. Check out the classifieds.

 

thanks viking, i just hope i can get everything together and in order come novemeber tuning. im really stressing my bank account to get it all in order.. im hoping my boss will be alright with me getting some OT in this fall.

 

I presume you are talking about flywheel horsepower. 350 whp on a Dynopak would equate to about 400 whp on a DynoJet (which is what most people on this board quote). Since it appears that there has been precisely one 400 whp stock turbo car, an average of 400 whp in your area would be strange.

The dyno thread lists quite a few stock turbo cars. Most are in the 290-320 whp range, with a few higher.

https://www.rx7club.com/time-slips-dyno-121/dyno-graphs-229717/

 

I'm talking about whp. His Dynapack runs very close to Dynojets but a tad bit on the low side.

Here's my buddies car on straight 93 octane, no meth or water injection. Same dyno.

495 whp on 93 octane

 

wow holy schnikes!! thats impressive.. dang ill crap my pants if down there steve pulls out over 350whp out of my car! that will rule and make me wonder what mods are left to do besides single.. lol

you guys think i should invest in meth injection since i will be running 14-15psi or say put it elsewhere such as an intercooler sprayer or something?

 

The above Dyno Graph was from a single turbo car.

Meth Injection would be a wise investment. Intercooler Sprayer would be a bad investment.