It's been a bit if a wait but my USM C4 HSR has finally arrived.

Looks good to me, did a quick test fit before I pulled the heads off and I only needed to grind a bit of the oil pressure fitting to allow it to slide back enough for the manifold bolt holes to line up.
Also had to take a bit off the throttle cable bracket to allow it to clear the fuel rail.

The large cap distributor is supposed to fit but seems really tight I may go with the small cap version to make installation easier, will have to wait for the heads to come back before I have a bit more of a play with it.

Some pic's of it below (hope it works).















I ordered it unpainted as I want to get it polished, the top has some back sealer in the old bolt holes which I am not too keen on, I will probably puy some dummy hex bolts in them.
I will also need to remove the coolant outlet from the bottom of the throttle body so it will clear the thermostat housing but I was going to do that bypass anyway.

 

Interesting.

 

Man that looks really good! I am always anxious to hear about an intake other than a mini or superram. From what Badss posted a while ago it seems like a great street intake. Keep us posted!

 

Lay a straight-edge along the intake flanges and use a feeler gauge
to check any visual gaps, paying particular attention to where the
floors of the runners terminate at the flanges.

My vote is to consider opening the radius further for the oil pressure
sender - it looks like there is contact shown below.



Thanks for the photos.

.

 

nice setup. the guy who welded it could use a little practice though.

 

Excuse my lack of knowledge, but what the heck is it?

 

It's a Holley Stealth Ram intake modified to fit under the stock hood of a C4. Forum Vendor USM is making them


Looks good keep us informed

 

I sort of see now why the original price was so high, there is a lot of work on that piece,,,, an incredible amount of welding.

Also on the oil pressure fitting, you can use a galvanized 1/8 nipple to clear the intake but I would file it down or air grind it down, either way..

I may be biased but I like mine better

 

I did not take an "after" picture but that's what I did, I ground a bit off the bottom of the oil pressure fitting, I was not too keen to take a grinder to the newly arrived manifold incase I stuffed it up.
I figured it would be easier to replace the fitting than the maniforld

I will check it for trueness as per Slaloms suggestion when I get home.

 

My instructor would have knocked my helmet off if I did that.

 

Definately a TON of work involved on that intake. Definately aint the prettiest thing i've seen but to even get to that point takes some skill.

HSR is a great intake, you'll like it. Just give it the heads and cam to really compliment it. It will love to pull to 6500

 

 

Currently I am planning a relatively mild build, I have the 113 heads and will get those rebuilt (ported/valves/springs etc) and a matching cam and longtube headers.

Don't have the budget for new heads or bottom end work, if the bottom end lets go then I will look at a extensive build.
It's my daily driver (120k) with the occational 1/4 run so dont want it too wild.

My welding skills are not existant so not really qualified to judge but I am generally happy with it (provided it does not leak) .

 

I have been torn between a miniram and HSR..problem with the HSR is that I was looking at cutting into my Firebird Formula hood bracket to make it fit vs. buying a miniram that would clear with no problems.

With the shortened version of the HSR doesn't it become very close to the miniram...shorter runner length. I am thinking this version (modded UMC HSR) would fit under my Formula hood with no clearance issues...but I am wondering for the extra bucks to mod if it's just cheaper to buy a mini?????

Thanks

 

You are correct, the price is now very close to a MR. I asked how much length was cut off the runners, but USR did not answer that question. They only said it was insignificant. Judging by the pics, I would say the length appears essentially unchanged.

From a technical/theoretical perspective, the HSR runners are about twice a long as the MR (~6" vs ~3"), which should help low-mid performance a bit (compared to the mini). On dynos and in simulations, the HSR should have 10-20 advantage in TQ/HP from 2500-5500 rpms. The MR is better up top. TPiS claims the MR will be slightly more responsive in off-idle performance. Their reason is it's easier to oscillate a shorter column of air. (I haven't any other feedback to suggest if this was sales dribble).

WWW.StealthRam.com has some comparisons if you haven't seen that site. Notice too, they list the MR as tuning the max power about 500 rpms higher than the HSR.

Compare these aspects to your needs to help with your final selection.

Edit:
To the OP... Did they thread the sensor bungs (holes) in the back of the plenum, or do you have to do that?

 

Thanks for the explanation, I like the HSR if the USR mod would work on my formula. But I also wanted to be able to pull the rpms to 6000-6500...will the HSR do that?

I noticed from some comparisons on one site to the mini..that the miniram was tuned rich and the HSR was tuned lean...I wished there was a thread with the tunes equal as a rich tune is not going to make as much hp as a leaner one.

 

Again, look at StealthRam.com.... They say peak occurs between 5800-6200 rpms. An engine sim run by another Forum member showed peak TQ at 5K rpms and peak HP at 6K rpms. I believe racers pull a few hundred rpms PAST peak before shifting.

The sim was with long tubes, 180 AFRs and a 268XFI comp cam. Showed it making about 420hp at peak. 195's simmed at 15hp more.

For street/strip, it's a not a bad choice.

 

i peak at 6250 rpm and shift by 6500 on my 383 with a fairly mild 230 degree cam. It will pull as high as you want it to, and they flow pretty good out the box.

I've seen a 355 combo with a hotcam like cam peak at 6400 with the HSR so they can rev up

 

Great...only dilema now is weighing the cost between a Miniram and modified HSR to fit underneath my 91 stock Formula hood. Those numbers and info provided is exactly what I was looking for especially with respect to the heads because I planned on keeping my 350 and just adding one of those intakes, headers, and possibly a cam...I will probably wait on the heads.

Intake will definetly be my first motor mod...then headers. Already added a catback.



Convas

Is there a link for the modded HSR?

Thanks

 

My only basis for comment on the HSR is the SuperRod test done several years ago with a 383, trick flow heads, 10-1 cr, 236/242 hyd roller cam.

In that test, they tested just about every TPI intake in the book and I personally thought the HSR won the test..... going out of memory, the following are the results of the MR, SR and HSR.....

Superram = 480 HP @ 5600 rpm with 505 ftlbs at somewhere around 4000 rpm

Holley Stealthram = 500 HP @ 6000 rpm with 490 ftlbs @ somewhere around 4500 rpm

TPIS Miniram = 505 HP @ 6200 rpm with 470 ftlbs @ somewhere around 4800 rpm.

I think all 3 intakes did pretty good..... As you might expect, the Superram had the most TQ, but was behind the others by 20-25 HP, the HSR did great, good compliment of torque and hp..... thus, I give it to the edge over the MR simply because it was only 5 hp shy of the MR, but it had a solid 20 ftlbs more torque...... and this test is about as real world as you can get considering it was a 383, 10-1 cr and an off the shelf cc cam with typical aftermarket off the shelf aluminum cylinder heads.

I would run the HSR, and might someday still, but I already own the Miniram, so will start with it on my big cube motor...... I think I am going to wait for somebody to have one just sitting around while they are awaiting their engine build or something and borrow it and do my own comprehensive track comparison test of the MR vs HSR on a big cube sbc...... I'll do the same with a Superram if somebody has one laying around, I sold mine a while back.