HSR vs TPI
HSR vs TPI
ok so im in desperate need of a new fuel system.. ive had 3 fuel pressure regulators break on me.. im looking into the holley stealth ram with the holley fuel rails and a kirban fuel reg.. or modifying my fuel rails for an external reg. im just wondering comparitevly not a dyno chart but driving the cars does the stealth ram have that low end torque that tpi does? with the shorter runners i just dont think it will and thats wut i love.. torque at 2 grand ive read a bunch of the other threads and none of them realy addressed the feel rather then the numbers
Junior Member
Joined: Feb 2007
Posts: 85
Likes: 0
From: Belleville,IL
Car: 92 Formula
Engine: 383 248/256 cam
Transmission: 700r4 3500 stall
Axle/Gears: 9" 3.89 gears detroit locker
Re: HSR vs TPI
Well we just finished my Hsr swap on my 92 bird. Yeah I lost a little low end not much at all really but my car also has a 2800 stall converter though too so it does help with the low end but now the car pulls smooth to 5500 rpm with no other changes but the intake same stock size throttle body also. If I were you I would consider the swap you might need a converter if you don't already have one though just my opinion.
Joined: Jul 2003
Posts: 10,524
Likes: 204
From: NYC / Jersey
Car: 1990 Trans Am GTA
Engine: Turbo 305 w/MS2
Transmission: 700R4
Re: HSR vs TPI
^ Swapping to an HSR will result in some lower end torque loss over the stock TPI system, but this very same torque can easily be brought back with the proper camshaft....
Joined: Sep 2003
Posts: 25,895
Likes: 429
From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: MWC 9” 3.00
Re: HSR vs TPI
i just did the swap from TPI to HSR on my all stock L98. i did notice a little low end loss but i have a 2800 stall converter. from a 30 mph punch it doesnt have the kick it once had, but its not that big of a deal. it still has some kick, just not as much. The top end gained over 4000 rpms is what makes my day. big improvement.
i did 1/4 mile testing and so far, it appears my 1/8 mile trap speed is alittle slower than it was with TPI, but the top end is 1 mph higher on average. ET's are fairly close to each other but TPI was raced in cooler weather.
i went 1.75 60 foot with TPI and ran 8.59 1/8 mile. with HSR i ran 1.82 60 foot with alittle spin, and ran 8.62 1/8 mile. that shows how much better HSR is over TPI even on a stock motor.
i did 1/4 mile testing and so far, it appears my 1/8 mile trap speed is alittle slower than it was with TPI, but the top end is 1 mph higher on average. ET's are fairly close to each other but TPI was raced in cooler weather.
i went 1.75 60 foot with TPI and ran 8.59 1/8 mile. with HSR i ran 1.82 60 foot with alittle spin, and ran 8.62 1/8 mile. that shows how much better HSR is over TPI even on a stock motor.
Joined: Sep 2003
Posts: 25,895
Likes: 429
From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: MWC 9” 3.00
Re: HSR vs TPI
well i mean its there its just not quite as strong as before. its not a big difference tho. the HSR makes a flat torque curve which is better to have anyway.
the only way i'll know for sure is when i take the car out to the track in november when its cold outside and see if i can match TPI's best 60 foots. i have a feeling it will be close to them but maybe a hundreth or so off. that kinda difference you cant really feel
the only way i'll know for sure is when i take the car out to the track in november when its cold outside and see if i can match TPI's best 60 foots. i have a feeling it will be close to them but maybe a hundreth or so off. that kinda difference you cant really feel
Re: HSR vs TPI
I'm running and HSR, vortec heads and an LT4 Hotcam with a 3000 stall and 3.73 gears and the car is a torque animal from stop to 5600 rpm. Don't forget about suspension mods to get all that new power to the ground. You just have to match all the components and not just slap on a steath ram to a stock setup and expect it to be a monster. I wouldn't be surprised if you just put a steath ram on a stock tpi engine that you would be very disapointed with the performance from 0-4000 rpm, where 99% of street driving is.
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Supreme Member
iTrader: (1)
Joined: Feb 2000
Posts: 7,964
Likes: 4
From: Norfolk, VA. USA
Car: 86 Trans Am, 88 Formula
Engine: 95LT4, 305TPI
Transmission: T56, T5
Re: HSR vs TPI
I gained 5mph in the 1/4 with an HSR on my bone stock 305.
It's still quite slow though, 15.2@93mph.
It's still quite slow though, 15.2@93mph.
Supreme Member
iTrader: (8)
Joined: Sep 2004
Posts: 1,896
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From: Charles County, Maryland
Car: 2000 BMW M5
Re: HSR vs TPI
If you want to sacrifice a ton of HP above 4500 rpms, where you need it, for a little more low end grunt, TPI is for you. If you are running somebody WOT all the action is going to be above where TPI performs. I swapped TPI to HSR and did not notice that much of a low end power loss at all. I can still burn the tires from a slow roll with the HSR, throttle response is still excellent.
Supreme Member
Joined: Mar 2002
Posts: 1,176
Likes: 0
From: Springfield, MO
Car: 92 T/A VERT
Engine: LB9
Transmission: AUTO
Axle/Gears: 7.5 / 3.42's
Re: HSR vs TPI
Well said 327. I've never understood peoples love affair with tpi. So you gain a couple of ft lbs around 3000rpm's, big deal. After that the things run like a late 70's smogger, and they're a pia to work on. First chance I get, I'm throwing mine in the trash.
Supreme Member
iTrader: (8)
Joined: Sep 2004
Posts: 1,896
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From: Charles County, Maryland
Car: 2000 BMW M5
Re: HSR vs TPI
Don't trash the TPI, it's worth $300 to someone who likes the tow truck intake. The one thing TPI does do, is look really really cool with the stock drawn aluminum tubes. I didn't want to look cool and lose power as an expense though.
Joined: Sep 2003
Posts: 25,895
Likes: 429
From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: MWC 9” 3.00
Re: HSR vs TPI
i happen to like how the HSR looks. i painted it along with the valve covers and i think it looks pretty good.
Joined: Jul 2003
Posts: 10,524
Likes: 204
From: NYC / Jersey
Car: 1990 Trans Am GTA
Engine: Turbo 305 w/MS2
Transmission: 700R4
Re: HSR vs TPI
Originally Posted by gmgod
I've never understood peoples love affair with tpi.
Joined: Sep 2003
Posts: 25,895
Likes: 429
From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: MWC 9” 3.00
Re: HSR vs TPI
probly that setup with a HSR or miniram would have went 10's at 120+. TPI can be made to go somewhat fast but your working with a 0-5000rpm range and only so much power can be made from that.
Member

Joined: Jan 2007
Posts: 206
Likes: 0
From: Huntley, Il
Car: 89 ws6
Engine: 355 afr195, hsr,gmpp cam, hs rr,
Transmission: t-5
Axle/Gears: 3.08
Re: HSR vs TPI
There is one good way to overcome this and that is with a turbo system on the car. Then you have what guys with 3.8 turbo cars have and keep the power below 5500. You do break less parts that way. I am happy wiht my stealth ram though and being able to pull past 600k and be making power was a good feeling.
Joined: Jul 2003
Posts: 10,524
Likes: 204
From: NYC / Jersey
Car: 1990 Trans Am GTA
Engine: Turbo 305 w/MS2
Transmission: 700R4
Re: HSR vs TPI
Originally Posted by Orr89RocZ
probly that setup with a HSR or miniram would have went 10's at 120+. TPI can be made to go somewhat fast but your working with a 0-5000rpm range and only so much power can be made from that.
Joined: Jul 2003
Posts: 10,524
Likes: 204
From: NYC / Jersey
Car: 1990 Trans Am GTA
Engine: Turbo 305 w/MS2
Transmission: 700R4
Joined: Sep 2003
Posts: 25,895
Likes: 429
From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: MWC 9” 3.00
Re: HSR vs TPI
Orr89RocZ, there is no question that an HSR would perform better, especially with a camshaft custom ground to maximize on it's performance potential. But you have to admit, that is a pretty damn impressive time for a stock TPI system (albeit ported out). Oh, and the owner of that vette has since ran it into the 10's (that's an old vid). I'll try to find a more recent run.... 

Joined: Jul 2003
Posts: 10,524
Likes: 204
From: NYC / Jersey
Car: 1990 Trans Am GTA
Engine: Turbo 305 w/MS2
Transmission: 700R4
Re: HSR vs TPI
^ Could definitely find out for you bro, just gimme a little time. A few of those guys run every now and then on the nights that I usually go to the track (Wednesday's & Friday's), w/the majority of them mainly running on Saturday's & Sunday's....
Joined: Sep 2003
Posts: 25,895
Likes: 429
From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: MWC 9” 3.00
Re: HSR vs TPI
thats cool man, i thought maybe they would have the combo posted on a vette site or something. i'm on a few of the vette sites but its been awhile since i browsed through there
Joined: Feb 2001
Posts: 8,494
Likes: 411
From: Sophia, NC
Car: 2016 Camaro SS + 1986 Z28
Re: HSR vs TPI
Guys, like all things in life, everyone wants something different. For all out performance, i think most of agree that the TPI is NOT the choice. Some of us are strictly show, some are just drivers, some just don't want to do too many mods. There are plenty of FAST TPI cars out there, but in the end, it's not a top notch performer anymore.....
...but I still love mine.
...but I still love mine.
Member

Joined: Jan 2007
Posts: 206
Likes: 0
From: Huntley, Il
Car: 89 ws6
Engine: 355 afr195, hsr,gmpp cam, hs rr,
Transmission: t-5
Axle/Gears: 3.08
Re: HSR vs TPI
Guys, like all things in life, everyone wants something different. For all out performance, i think most of agree that the TPI is NOT the choice. Some of us are strictly show, some are just drivers, some just don't want to do too many mods. There are plenty of FAST TPI cars out there, but in the end, it's not a top notch performer anymore.....
...but I still love mine.
...but I still love mine.

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