Who's running Mikuni HSRs? Experience with Vintage Performance Developments?

[GoldHawg]

And what is your experience? How was the installation? I have a friend that will joining us soon that just picked up a 69 SPL w/U20 5 speed w/SUs. He has upgraded to the EI Dizzy and wondering if replacement carbs might be in his future for better tuning and driveability. The one guy selling Mikuni kits (Vintage Performance Developments) really claims drastic improvement for HSRs over SUs, but I would suspect someone selling that to say that. Looking for real world experience. He has sold several kits for Datsuns, and wondering if someone on the forum can speak to that experience. One poster from about 5 years ago says he got ripped off by the guy so I'm suspicious for lots of reasons. But he is still in business and claims he sent a roadster one out yesterday.

http://www.v-performance.com/products/air_fuel.html

We're also considering EFI (separate thread), but if we stay carbs looking at either just redoing with Z-therapy or the Mikuni setup, if it is as good as the proponents say.

[greydog]

First thing I'd ask is "Why". By that I mean, realistically, what do you hope to achieve? I see mention of tuneability but wonder if your pal really has the O2 sniffers and dyno time to actually tune a set of carbs.
Not trying to talk you out of the HSR's, in fact, I'd like to see someone spend the time and money to figure the setup out.
If I were seriously going to go with HSR's, I'd ask the owner for the contact info for at least three customers with similar engines. If he refuses, I'd move on.
I suspect that if you're contemplating HSR's or some diy injection, you'll need, at the minimum, a sound engine and a wide band O2 sensor installation.
Caution....I have met very few people who, after spending a few thousand dollars and a lot of time, were honest enough to say it got them nothing but poorer.
Dan

[Gregs672000]

SU carbs work very well when they are in good shape, they're just not as easily tunable as those with jets, accelerator pumps, etc. You're guessing with a graduated needle that relies on it being correct based on the thickness of the needle where ever engine vaccum dictates. Setting up carbs with jets requires some general knowledge of how things work, but with a wideband the average Joe can really get a good idea of how well jetted the carbs are. I bet they can be initially set relatively close, then adjusted to the engine and environment. I've messed with jetting for 30 years and the wideband was a game changer. I always know if I'm rich, lean or just right under all circumstances, and with jets and accelerator systems you can adjust it accordingly and incrementally.

[nismou20]

There was fellow who had this very setup and posted some Dyno numbers but I was disappointed as they were comparable to a stock U20. Could of been that they needed a little more fine tuning but I decided against them after tearing through my SUs. SUs are great all around carbs, so easy to tune and with different needles. As you probably know with HSR you are controlling the slides with your foot and rolling into the power. In theory you should see more mid/top end. The guy with V-performance suggested going with the 45 rather than the 48. I’d be curious to see someone go thru with this.

[Pjackb]

Goldhawk,
I did a ton of research on these when I was still figuring out what to for my engine and had a chance to speak with John Parker the Owner of Vperformance, JohnW who had a set on his U20 and a few TR6 owners. So to answer some of your questions this is my take take on it for what it’s worth.

- If you asked JohnW he would tell you he would do it again no hesitation. First He dynoed at 110hp and 110lb/ft at the wheels on an otherwise stock engine which is closer to what the stock Solex cars are doing but more importantly is how the power is delivered with tons of midrange and superb throttle response (this is a common theme with everyone i’ve spoken to) . The one mistake he said he made is going with 45s instead of the 42 as recommended by Mr Parker. These things have a lot of flowing capabilities.

- Corey who is the member you are referring to had a very nasty experience with mr Parker and has not been shy about posting about it and he is not the only one it seems. if you search John Parker V-Performance you will find a lot of posts going back many years of people with bad experiences with him on a number of products, now there’s always 2 sides of a story but as the saying goes where there’s smoke there’s usually fire and I would be very hesitant to buy from him. JohnW bought his of eBay and built his own linkage and accelerator pump trigger

- This is a great upgrade especially if you add a B cam to the equation and can do the linkage conversion yourself and will run you much cheaper than a Solex conversion with the cost of the intakes now.

In the end i didn’t end up using them on my car because I had the opportunity to get PHHs but where I to get a second car on SUs this would be on my list

[Gregs672000]

I took a look at the website and these look like a really nice set up, easy to tune with a well written and systematic procedure. I would do this way before messing with EFI. I would contact people who have done this to figure out the linkage.

[Alvin]

Glenn has been running these for over a decade in his SRL:

I'm forgetting his username

[talladega]

For what its worth I am in the process of installing a pair of HSR42's on my 1968 2000. I bought them from Mr. Parker and have nothing bad to say about the transaction. He responds quickly to questions and has been helpful. He also did exactly what he said as far as shipping the order. Maybe I was lucky. The car should be running next week and I'll post my impressions.

[greydog]

Great to hear. I will be very interested in your immediate and long term impressions.
Thanks for posting the powwow yup.
Dan

[talladega]

Ran into a number of small issues during installation but its finally completed and I started it for the first time this afternoon. Sounds great but did not drive it. Will be getting an O2 wideband soon as next step in tuning. I will update when I have it on the road.

[Gregs672000]

Fun stuff, you'll love having the wideband.